# 2013 Roubaix SL4



## new2rd (Aug 8, 2010)

No rumors, but did anyone see a new Roubaix being used this past weekend? I thought with the cobbles, this would be a good time to spy some pictures. Anyone? :idea:


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## [email protected] (Jan 15, 2010)

I Am SpecializedPhotos: Contador visits Specialized HQ in California

....this could be the new roubaix sl4 frame...


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## DonDenver (May 30, 2007)

[email protected] said:


> I Am SpecializedPhotos: Contador visits Specialized HQ in California
> 
> ....this could be the new roubaix sl4 frame...


^ I think you're right [email protected], but Conti sure looks like he's thinkun..."I don't know what the hell this is but have you saved me about 100 of those Tarmac SL3 frames...and no...not that SL4 or Vengful crap please".


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## [email protected] (Jan 15, 2010)

New Zertz dampers in the seatstays....??

Prototype Roubaix for Tour of Flanders? (Photo) | The Hub | Bicycling.com


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## Chris-X (Aug 4, 2011)

[email protected] said:


> New Zertz dampers in the seatstays....??
> 
> Prototype Roubaix for Tour of Flanders? (Photo) | The Hub | Bicycling.com


Yeah, it looks like they went all in with that zertz design with no carbon fiber structure at the bottom aft of the zertz in the seat stay.

Before people were referring to the Zertz as maybe just ornamentation that one could remove without any effects on ride.. Now it seems that the material maybe compressed when the seat stay flexes. I wonder if the chain stays are much beefier.


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## roadworthy (Nov 11, 2011)

Chris-X said:


> *Yeah, it looks like they went all in* with that zertz design with no carbon fiber structure at the bottom aft of the zertz in the seat stay.
> 
> Before people were referring to the Zertz as maybe just ornamentation that one could remove without any effects on ride.. Now it seems that the material maybe compressed when the seat stay flexes. I wonder if the chain stays are much beefier.


Sure does look like they went all in. But anybody who has ridden the SL3 Roubaix knows that that the Zertz elastomers work...in particular the SL3 which is in its second generation with measurably more seat stay displacement than earlier Roubaix albeit with greater lateral stiffness.

Looks like the 3rd gen of Zertz is on deck. No doubt the next gen Roubaix will be one hell of a bike...whether they call it the SL4 a la Tarmac or not. I try to visualize how the seat stay can have structural integrity with the open channel zertz design. It makes sense. In tension CF is ridiculously strong and therefore the single sided continuous CF connection will be sufficient. In compression, the pronounced C channel of CF basically pivots and compresses the compliant elastomer...and when doing so, the elastomer can compress vertically and displace laterally rearward out the open channel. I bet that design has a profound influence on ride quality...has to. The bar continues to be raised. Trek recently upped the ante with their new endurance offering that Cancellara will be racing at the Roubaix...a mechanical pivot at the seat tube ala off road, rear suspension lite...no doubt gleaned from kinematic studies performed with their 29er Fisher duallies.

All I can say is..if the next gen Roubaix is better than the current one, which no doubt it will be...gonna be a lot of happy riders out there.


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## Chris-X (Aug 4, 2011)

roadworthy said:


> Sure does look like they went all in. But anybody who has ridden the SL3 Roubaix knows that that the Zertz elastomers work...in particular the SL3 which is in its second generation with measurably more seat stay displacement than earlier Roubaix albeit with greater lateral stiffness.
> 
> Looks like the 3rd gen of Zertz is on deck. No doubt the next gen Roubaix will be one hell of a bike...whether they call it the SL4 a la Tarmac or not. I try to visualize how the seat stay can have structural integrity with the open channel zertz design. It makes sense. In tension CF is ridiculously strong and therefore the single sided continuous CF connection will be sufficient. In compression, the pronounced C channel of CF basically pivots and compresses the compliant elastomer...and when doing so, the elastomer can compress vertically and displace laterally rearward out the open channel. I bet that design has a profound influence on ride quality...has to. The bar continues to be raised. Trek recently upped the ante with their new endurance offering that Cancellara will be racing at the Roubaix...a mechanical pivot at the seat tube ala off road, rear suspension lite...no doubt gleaned from kinematic studies performed with their 29er Fisher duallies.
> 
> All I can say is..if the next gen Roubaix is better than the current one, which no doubt it will be...gonna be a lot of happy riders out there.


I'm riding an SL 2 S-Works and the mechanic at the LBS was shocked at how smooth it was. A lot of that comes down to the fact that I'm riding 28mm tires at 80 psi or lower on 32 spoke box section rims. I don't plan on riding pave anytime soon so I really can't imagine my setup getting much better, although both Trek and Specialized are claiming that the Domane and Roubaix are stiffer than their last generation of Madone's and Tarmacs respectively.

At a certain point, you have to pedal the bike and you're going to feel big hits no matter what. I'm liking the Calfee Adventure at this point in time too.


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## roadworthy (Nov 11, 2011)

Chris-X said:


> I'm riding an SL 2 S-Works and the mechanic at the LBS was shocked at how smooth it was. A lot of that comes down to the fact that I'm riding 28mm tires at 80 psi or lower on 32 spoke box section rims. I don't plan on riding pave anytime soon so I really can't imagine my setup getting much better, although both Trek and Specialized are claiming that the Domane and Roubaix are stiffer than their last generation of Madone's and Tarmacs respectively.
> 
> At a certain point, you have to pedal the bike and you're going to feel big hits no matter what. I'm liking the Calfee Adventure at this point in time too.


Believe the difference is...a big hit on a Roubaix is a BIGGER hit on a stiffer more upright angle race bike. The bikes continue to get better but Eddy M in his prime on a 25 lb steelie is still gonna drop all the guys here and half the pro riders out there on their carbon wunderbikes to be sure. Like you say, you still have the pedal the thing and its about the engine. That said, the new bikes are pretty amazing in terms of comfort and performance.


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## EWT (Jul 3, 2011)

Chris-X said:


> I'm riding an SL 2 S-Works and the mechanic at the LBS was shocked at how smooth it was. A lot of that comes down to the fact that I'm riding 28mm tires at 80 psi or lower on 32 spoke box section rims. I don't plan on riding pave anytime soon so I really can't imagine my setup getting much better, although both Trek and Specialized are claiming that the Domane and Roubaix are stiffer than their last generation of Madone's and Tarmacs respectively.
> 
> At a certain point, you have to pedal the bike and you're going to feel big hits no matter what. I'm liking the Calfee Adventure at this point in time too.


I just bought a leftover SL2 S-Works frame after riding a built up SL2 and a Madone 5.9 on the same route 5 minutes apart and the difference in ride was significant. I went in expecting the like the Madone better and ended up buying a SL2 frame (didn't like the component set on the built up bike). If they have improved it over the SL2, the ride must be pretty amazing.


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## roadworthy (Nov 11, 2011)

EWT said:


> I just bought a leftover SL2 S-Works frame after riding a built up SL2 and a Madone 5.9 on the same route 5 minutes apart and the difference in ride was significant. I went in expecting the like the Madone better and ended up buying a SL2 frame (didn't like the component set on the built up bike). If they have improved it over the SL2, the ride must be pretty amazing.


The ride of the SL3 is...what I call uncanny. After I built the bike and rode if for the first mile I said to myself, this bike feels as stiff as any I have ever ridden. My fear was the bike would be a bit soft living up to its rough road capability. Completely unfounded. Most of us that ride road bikes prefer a bike that feels a bit snappy...not unlike a stiff slalom ski you can load up the tail and spring into the next turn. I could feel the road...what I like...could feel the cracks in the side walk. The bike telegraphs feedback from the road...and yet doesn't fly up when hitting road disturbances...wheels feel planted...uncanny. A lot of stiff bikes bounce off rough road and hence the jarring sensation. Then I hit the first drop off and ledge as I crossed the road bracing myself for the inevitable jolt. It didn't come. I really couldn't believe it until I rode the bike some more. The bike completely mutes the big hits...and unlike Chris I ride 23c tires pumped up to 130 psi.
That said, a Sworks SL2 is one whale of a bike and a better bike than we are as riders.
The Roubaix SL4 is really going to be something.


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## [email protected] (Jan 15, 2010)

Pic of the new frame....:

New Specialized prototype spotted at Flanders | Latest News | Cycling Weekly

....when it is possible to order???


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## drazic (Mar 31, 2012)

I ride a Boonen SL2 Roubaix and it is a great touring bike.....
But i feel like getting a second bike for short races and triathlons. TT bikes are not my cuppa tea so was wondering if a Venge with aero bars or perhaps a Tarmac SL4 would be good?


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## Chris-X (Aug 4, 2011)

*Really?*



roadworthy said:


> The ride of the SL3 is...what I call uncanny. After I built the bike and rode if for the first mile I said to myself, this bike feels as stiff as any I have ever ridden. My fear was the bike would be a bit soft living up to its rough road capability. Completely unfounded. Most of us that ride road bikes prefer a bike that feels a bit snappy...not unlike a stiff slalom ski you can load up the tail and spring into the next turn. I could feel the road...what I like...could feel the cracks in the side walk. The bike telegraphs feedback from the road...and yet doesn't fly up when hitting road disturbances...wheels feel planted...uncanny. A lot of stiff bikes bounce off rough road and hence the jarring sensation. Then I hit the first drop off and ledge as I crossed the road bracing myself for the inevitable jolt. It didn't come. I really couldn't believe it until I rode the bike some more. The bike completely mutes the big hits...and unlike Chris I *ride 23c tires pumped up to 130 psi*.
> That said, a Sworks SL2 is one whale of a bike and a better bike than we are as riders.
> The Roubaix SL4 is really going to be something.


Why would you do that?


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## [email protected] (Jan 15, 2010)

Tom Boonen`s New Specialized Roubaix SL4:

Tom Boonen's New Specialized Roubaix SL4 | Cyclingnews.com

....:23:


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## roadworthy (Nov 11, 2011)

Chris-X said:


> Why would you do that?


Because I can...without detriment to ride. I weigh 190# without gear. What do many if not most do who buy a stiff racing bike? They can't deal with ride harshness and so sag tire pressure down increasing rolling resistance and flirt with pinch flats. Better solution? Buy a bike with a decent ride where you can run pressures up and you will still have a good ride, low rolling resistance and no pinch flats. Point is...the Roubaix SL3 doesn't need wider tires like other road bikes. I ride poor roads interrmittently. If I rode the dirt and broken road surfaces consistently I would run wider tires and reduce pressure. No need with such a superb frameset.


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## Chris-X (Aug 4, 2011)

roadworthy said:


> Because I can...*without detriment to ride*. I weigh 190# without gear. What do many if not most do who buy a stiff racing bike? They can't deal with ride harshness and so sag tire pressure down increasing rolling resistance and flirt with pinch flats. Better solution? Buy a bike with a decent ride where you can run pressures up and you will still have a good ride, low rolling resistance and no pinch flats. Point is...the Roubaix SL3 doesn't need wider tires like other road bikes. I ride poor roads interrmittently. If I rode the dirt and broken road surfaces consistently I would run wider tires and reduce pressure. No need with such a superb frameset.


If you're riding 130 psi on 23's it's detrimental to the ride, tire wear, cuts, wheel integrity, physical/psychological performance, ie, endurance. Those vibes for 5-7 hours really sap strength.

On anything but a velodrome, rolliing resistance will be higher, although you may save a tenth of a mph due to better aero. 

Here's a primer.

[The effect of whole-body vibration: a... [Arh Hig Rada Toksikol. 1993] - PubMed - NCBI

Good luck!


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## roadworthy (Nov 11, 2011)

Chris-X said:


> If you're riding 130 psi on 23's it's detrimental to the ride, tire wear, cuts, wheel integrity, physical/psychological performance, ie, endurance. Those vibes for 5-7 hours really sap strength.
> 
> On anything but a velodrome, rolliing resistance will be higher, although you may save a tenth of a mph due to better aero.
> 
> ...


Don't need a primer. I have read all the scholarship on the subject and understand the tradeoffs.
You forgot PV=nRT, wheel integrity is better due to less probability of strike through and the point is a Roubaix with hard tires is less fatiguing than other race bikes I have owned with tires @ 100 psi. I ride on relatively smooth surfaces most of the time i.e. very little vertical deflection and hence higher pressure works quite well.

Please produce support of your assertion that higher pressure promotes more cuts and increased tire wear. Would love to see proof.


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## Chris-X (Aug 4, 2011)

roadworthy said:


> Don't need a primer. I have read all the scholarship on the subject and understand the tradeoffs.
> You forgot PV=nRT, wheel integrity is better due to less probability of strike through and the point is a Roubaix with hard tires is less fatiguing than other race bikes I have owned with tires @ 100 psi. I ride on relatively smooth surfaces most of the time i.e. very little vertical deflection and hence higher pressure works quite well.
> 
> Please produce support of your assertion that higher pressure promotes more cuts and increased tire wear. Would love to see proof.


http://sheldonbrown.com/tyres.html

_•*An overinflated tyre is more prone to damage from sharp rocks and similar road hazards*.

The trade-off with this is that if you pump the tyre up too hard, you lose the benefits of pneumatic tyres: the ride becomes excessively harsh, and traction will be reduced. *In addition, extremely high pressures require a stronger (heavier) fabric and stronger (heavier) rim flanges. 
*
Rolling resistance does decrease theoretically with any increase in pressure, but with modern, high-quality tyres the rolling resistance at correct inflation pressure is already so low that the infinitesimal reductions gained are more than outweighed by the trade-offs. 
*In practice, riding surfaces aren't perfectly smooth, and overinflation actually increases rolling resistance, due to vibration*._


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## Scott in MD (Jun 24, 2008)

130 psi is a lot .... just sayin'.


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## roadworthy (Nov 11, 2011)

Chris-X said:


> Cycle Tyres and Tubes
> 
> _•*An overinflated tyre is more prone to damage from sharp rocks and similar road hazards*.
> 
> ...


At the end of the day each of us believe what we want and choose tire pressures that suit ourselves. The Vitorria tires I ride carry a max. pressure rating of 145 psi. Rims are hooked and secure. Ride quality is superb with the Roubaix at higher tire pressures for the roads I ride. Rolling resistance is excellent. As much as I admire the great Sheldon Brown and I have personally corresponded with him before his premature passing...you took his comments out of context. I don't ride road surfaces with sharp rocks on my Roubaix. You may. Further in my experience, a tire at higher pressure has a much lower tendency to pinch flat due to lower tire deflection when hitting a localized obstruction which causes a precipitous increase in localized tire pressure resulting in a pinched tube.
How about this? You ride the tire pressures you want and I will do the same? I used the 130 psi as an example. If PV=nRT went over your head, I air my tires in the house and outside I often ride in temps 20 degress F lower ambient temperature. Pressure is proportional to temperature. Therefore actual tire pressures I ride can be much lower. Further I stagger tire pressures front and rear because front and rear tires are not loaded equally on a road bike. Tire foot print area is proportional to tire pressure for the same weight bearing. 

I am a scientist. To give you greater perspective, I don't always ride with high pressure. If I know I will be riding a particularly rough course, I lower it...or riding on a particularly hot day. I will state again, I have read all the scholarship that you have...likely more because of my training.


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## PJ352 (Dec 5, 2007)

Scott in MD said:


> *130 psi is a lot* .... just sayin'.


Agreed. Even with a rider weight of ~180 lbs., Michelin's starting point is 116 PSI for 23c tires/ 102 PSI for 25c's - and they recommend tailoring from there.

http://www.michelinbicycletire.com/michelinbicycle/index.cfm?event=airpressure.view

I like their explanation of why experimenting is important, and IME it holds true.

_"Michelin engineers have found that there's a certain amount of deflection in the tire profile that's optimal for balancing grip, efficiency, comfort and durability. That deflection is based on the tire's construction and the weight of the rider. Obviously, your style of riding can have an effect too..."_


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## [email protected] (Jan 15, 2010)

Tom Boonen and Roubaix SL4 triumph at Paris-Roubaix.....:

http://www.bikeradar.com/road/news/article/boonen-triumphs-at-paris-roubaix-33656/


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## dcgriz (Feb 13, 2011)

Chris-X said:


> Rolling resistance does decrease theoretically with any increase in pressure, but with modern, high-quality tyres the rolling resistance at correct inflation pressure is already so low that the infinitesimal reductions gained are more than outweighed by the trade-offs.
> *In practice, riding surfaces aren't perfectly smooth, and overinflation actually increases rolling resistance, due to vibration*.[/I]




+1. Additionally, decreasing the tire pressure by 10-20 psi will do significantly more for the ride comfort than anything frame related. The Roubaix contribution to the cycling world is the taller HT with its more upright, more comfortable posture and, as some would insist, the Zertz inserts.The Zertz inserts are thru-bored on my 2009 Roubaix Elite and screwed on my 2011 Roubaix Pro SL3. Maybe they will be glued on the new SL4? I'm sure they will drastically cushion the ride😉. Until then, wider tires inflated at 10-20 psi less than the 23s will work exceptionally well in cushioning the ride.


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## Scott in MD (Jun 24, 2008)

*Tarbaix SL1*

I transformed my Tarmac into a Tarbaix by adding 25mm tires (Roubaix Pros, no less) on HED 23mm wide rims, and flipping the stem ... but nothing I could do about the Zertz on the seatstays...

... so I wrapped some duct tape around the seatstays. WOW ... transformation. Smooth ride. Soaks up road vibration. Chalk up one more functional use for duct tape. I calculated that I cruise over rough roads with 6.7714 fewer watts at 20MPH.



Seriously ... I do like the ride quality with more air in the hoops ... makes me wonder as the Tarmac gets more agressive geometry (SL4 lower headtube by up to an inch versus SL3) and the Roubaix gets full suspension (ala Domane), and have you seen that goofy new seat post? ... anyone else think this creates space for a new bike in the Spesh lineup? A Tarbaix? I hope it comes in 575mm top tube ... just sayin'.


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## dcgriz (Feb 13, 2011)

Scott in MD said:


> I transformed my Tarmac into a Tarbaix by adding 25mm tires (Roubaix Pros, no less) on HED 23mm wide rims, and flipping the stem ... but nothing I could do about the Zertz on the seatstays...
> 
> ... so I wrapped some duct tape around the seatstays. WOW ... transformation. Smooth ride. Soaks up road vibration. Chalk up one more functional use for duct tape. I calculated that I cruise over rough roads with 6.7714 fewer watts at 20MPH.
> 
> ...


You forgot the seat post............that's a 33.333% increase in VRE (vibration reduction effect) scientifically speaking😜
Amateurs......


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## Chris-X (Aug 4, 2011)

roadworthy said:


> At the end of the day each of us believe what we want and choose tire pressures that suit ourselves. The Vitorria tires I ride carry a max. pressure rating of 145 psi. Rims are hooked and secure. Ride quality is superb with the Roubaix at higher tire pressures for the roads I ride. Rolling resistance is excellent. As much as I admire the great Sheldon Brown and I have personally corresponded with him before his premature passing...*you took his comments out of context.* I don't ride road surfaces with sharp rocks on my Roubaix. You may. Further in my experience, a tire at higher pressure has a much lower tendency to pinch flat due to lower tire deflection when hitting a localized obstruction which causes a precipitous increase in localized tire pressure resulting in a pinched tube.
> *How about this? You ride the tire pressures you want and I will do the same?* I used the 130 psi as an example. *If PV=nRT* went over your head, I air my tires in the house and outside I often ride in temps 20 degress F lower ambient temperature. Pressure is proportional to temperature. Therefore actual tire pressures I ride can be much lower. Further I stagger tire pressures front and rear because front and rear tires are not loaded equally on a road bike. Tire foot print area is proportional to tire pressure for the same weight bearing.
> 
> I am a scientist. To give you greater perspective, I don't always ride with high pressure. If I know I will be riding a particularly rough course, I lower it...or riding on a particularly hot day. I will state again, I have read all the scholarship that you have...likely more because of my training.


This may come as a shock, but the most brilliant scientists often disregard consensus, and try to eschew technical jargon.:thumbsup:

As a matter of fact, the most brilliant scientists of the 20th Century avoided as much as the "scholarship" as they could while still being able to understand the problems they were trying to solve.

Fortunately for us mere mortals on RBR, the classical problems of the forces encountered while riding a bicycle are mundane and widely understood.

Theory, empirical evidence, and in fact general concensus, DO happen to align with what I'm writing though.

You're free to carry on as before!:skep:


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## roadworthy (Nov 11, 2011)

Chris-X said:


> This may come as a shock, but the most brilliant scientists often disregard consensus, and try to eschew technical jargon.:thumbsup:
> 
> As a matter of fact, the most brilliant scientists of the 20th Century avoided as much as the "scholarship" as they could while still being able to understand the problems they were trying to solve.
> 
> ...


Nothing has stopped you from carrying on. In any event, you are amusing. 

I think you need a primer so will break it down for you because your trite references to commonly understood tire pressure tradeoffs are forgive me, a bit boring.

I was making a point about the ride quality of the Roubaix with high tire pressures.
Nothing you posted was a revelation. You basically just referenced other studies widely discussed on many bike forums. There are many of these links with a high degree of corroboration as you say.
We can debate every nuance...from aero profile of a wider rim and shorter tire height affect on thermodynamic boundary layer to diminishing return in rolling resistance relative to pavement irregularity. Design of experiences aka Taguchi methods are used all the time by tire engineers to better understand and isolate contributing factors and relative weight. We didn't even talk about carcass construction or TPI which is huge. The flipside to riding higher pressures than ideal for the set of boundary conditions 'you think is meaningful', is riding with low pressure to compensate for a stiff frame that many experience to be uncomfortable. This is common. A guy buys a stiff racing bike say like an early CAAD frameset and sags tire pressure below recommended pressures for his body weight relative to the 'ideals' of your posted links that reference optimal deflection relative to rider weight etc. They do this because their teeth are being rattled at your sense of 'ideal pressure'. They also do so at the risk of flirting with pinch flats. I believe you know what pinch flats are...the result of reduced tire pressure increasing localized tire deflection which pinchs the tube and can cause a blow out.. The 'point' is, the Roubaix doesn't need such a bandaid. It has a compliant ride at high tire pressure. I am 190#. I have ridden the bike with 100-135 psi, and there isn't a great differential to ride quality based upon the roads I ride. By contrast, other bikes over this spectrum of air pressure will manifest a considerable difference in ride quality. On some bikes I have owned anything over 120 psi becomes quite harsh. The Roubaix frameset is less sensitive to tire pressure in terms of compromise to ride quality compared to other stiff bikes I have owned and ridden. I hope this makes sense to you. In your words...the dynamic I speak of is quite common and widely understood and why many ride lower pressures than they should with compromise to rolling resistance and propensity to pinch flat...and yes some incremental aka negligible affect to aero drag to be further pedantic.


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## nismo73 (Jul 29, 2009)

Spesh website down for remodeling...maybe this is like when Apple is about to introduce something new. Specialized could be adding some official info on the SL4 Roubaix to their website - gotta keep up with Trek


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## Stumpjumper FSR (Aug 6, 2006)

nismo73 said:


> Spesh website down for remodeling...maybe this is like when Apple is about to introduce something new. Specialized could be adding some official info on the SL4 Roubaix to their website - gotta keep up with Trek


Keep up with Trek? I think you have this backwards


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## Chris-X (Aug 4, 2011)

*Thanks,*



roadworthy said:


> Nothing has stopped you from carrying on. In any event, you are amusing.
> 
> I think you need a primer so will break it down for you because your trite references to commonly understood tire pressure tradeoffs are forgive me, a bit boring.
> 
> ...


but I subscribe to the old fashioned view that things are more or less what they seem.

Plus I like cornering with softer, wider, tires.....:thumbsup:


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## roadworthy (Nov 11, 2011)

Chris-X said:


> but I subscribe to the old fashioned view that things are more or less what they seem.
> 
> Plus I like cornering with softer, wider, tires.....:thumbsup:


After all this discussion that you started by asking 'why' would I run high pressure...we have finally come full circle. I wouldn't ask you why you would run lower pressure for example. It is obvious...personal preference. I don't like running tires to the soft side. I flat less to the high side and prefer a firmer ride and sense when I am out of the saddle that I am not scrubbing my tires into the ground and negating speed. Your mileage may vary. I don't ride the ragged edge of corner adhesion. I believe this is a foolhardy way to ride a bicycle or a motorcycle....I love both. Many lay people subscribe to the notion that things are pretty much what they seem. They are rarely right however. They read a few links or published data and make false extrapolations from it. This is OK. It isn't brain surgery. Its ok for you to subscribe to this notion because it is all you have. You don't have the training to look deeper. The truth tends to be much more complex than that which includes the watershed Roubaix road bike which belies convention in terms of old paradigms in terms of frame stiffness portending a certain level of ride quality. Many for example choose a road bike size based upon top tube length. Most lay people find it convenient to think in simple terms. Perhaps you are such a person. Hey, life is easier like that isn't it? But guys like you won't create a Roubaix or an Ipad. The Roubaix's counter intuitive ride quality based upon its super stiff frame structure couldn't have been developed by a layperson. The design is counter to conventional thinking. It was developed by engineers using CAD and finite element computer modeling decoupling torsional stiffness from vertical deflection which historically have been related. The SL4 Roubaix will no doubt further decouple the two relationships. I know because I use these these computer tools as well. There is nothing old fashioned or intuitive about design at a higher level. Development is based upon analysis and no doubt countless design iterations to optimize geometry and carbon lay up which gives the new Roubaix its uncommon ride dynamics.
Enjoy the fruits of other science based designs is what I say to you but the truth you gloss over is very different from the actual physics involved.


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## Scott in MD (Jun 24, 2008)

*Tire Pressure and the Ideal Gas Law (Just Sayin')*

Roadworthy .... we really don't care what pressure you ride ... you are probably faster than me at 60 psi! ... but I hate to see Clapeyron's brilliant work misrepresented ...., the Ideal Gas Law does in fact apply.... P2 = P1(T2/T1) since constant volume is a reasonable assumption ... but temperature has to be converted to the Kelvin scale (not Farenheight or Celsius) where absolute zero is -273 C .... so taking your hoops outside from 25C to 15C is taking them outside from 298K to 288K ... and P2 will be about 97% of your original pressure .... and air inside tires will also heat up from the road friction even though outside ambient temperature is lower ... so probably your air pressure outside is pretty close to 130 psig just like inside. And that's seems a little high to me .... just sayin'.


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## roadworthy (Nov 11, 2011)

Thanks for the primer on the Ideal gas law Scott. It was made as a counterpoint to how ridiculous assertions are about 'high' air pressure...including yours. So what?...is the point. I have been riding road bikes since the 60's...every possible tire shape, size, TPI...sew ups, clinchers and even tubeless at every conceivable pressure.. What does 10-15 psi psi matter in the grand scale? Nothing. It is noise. Some guys like to ride with 80 psi..hopefully fly weights, and I have ridden with heavy riders that ride at 140 psi. All get down the road just fine. Its a moot discussion. 130 psi will seem ridiculous to a light rider but not a heavy guy who has a history of pinch flats at low pressure.
It is mostly personal preference at the end of the day because there about 10 parameters worthy of discussion when it comes to tire pressure. It depends what you want to optimize.


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## Scott in MD (Jun 24, 2008)

Yikes.

Ridiculous?

The only thing I said was "130 psi is a lot .... just sayin'. "

Ridiclous?

Try decaf. Just sayin'


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## roadworthy (Nov 11, 2011)

Scott in MD said:


> Yikes.
> 
> Ridiculous?
> 
> ...


try nitrogen...lol.


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## Chris-X (Aug 4, 2011)

roadworthy said:


> After all this discussion that you started by asking 'why' would I run high pressure...we have finally come full circle. I wouldn't ask you why you would run lower pressure for example. It is obvious...personal preference. I don't like running tires to the soft side. I flat less to the high side and prefer a firmer ride and sense when I am out of the saddle that I am not scrubbing my tires into the ground and negating speed. Your mileage may vary. I don't ride the ragged edge of corner adhesion. I believe this is a foolhardy way to ride a bicycle or a motorcycle....I love both. Many lay people subscribe to the notion that things are pretty much what they seem. They are rarely right however. They read a few links or published data and make false extrapolations from it. This is OK. It isn't brain surgery. Its ok for you to subscribe to this notion because it is all you have. *You don't have the training to look deeper*. The truth tends to be much more complex than that which includes the watershed Roubaix road bike which belies convention in terms of old paradigms in terms of frame stiffness portending a certain level of ride quality. Many for example choose a road bike size based upon top tube length. Most lay people find it convenient to think in simple terms. Perhaps you are such a person. Hey, life is easier like that isn't it? *But guys like you won't create a Roubaix or an Ipad.* The Roubaix's counter intuitive ride quality based upon its super stiff frame structure couldn't have been developed by a layperson. The design is counter to conventional thinking. It was developed by engineers using CAD and finite element computer modeling decoupling torsional stiffness from vertical deflection which historically have been related. The SL4 Roubaix will no doubt further decouple the two relationships. I know because I use these these computer tools as well. There is nothing old fashioned or intuitive about design at a higher level. Development is based upon analysis and no doubt countless design iterations to optimize geometry and carbon lay up which gives the new Roubaix its uncommon ride dynamics.
> Enjoy the fruits of other science based designs is what I say to you but the truth you gloss over is very different from the actual physics involved.


My current research problem has lead me to believe M-theory was utilized in the development of the Roubaix.



Scott in MD said:


> Yikes.
> 
> Ridiculous?
> 
> ...


You really believe caffeine can cause assumption, fantasy, and delusion?


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## roadworthy (Nov 11, 2011)

Chris-X said:


> My current research problem has lead me to *believe M-theory was utilized in the development of the Roubaix.
> *
> 
> 
> You really believe caffeine can cause assumption, *fantasy, and delusion*?


Sad...goodbye.


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## dcgriz (Feb 13, 2011)

I am wondering if any of you who happen to ride any of the Roubaix SL3s with the carbon seatpost, realize how much the post oscillates while riding. I have a 58 Pro SL3 with about 7" to 8" inches of seatpost showing and this thing moves. I took a video on the trainer the other day checking on Q-factors and the like and that's when I realized it. 
It seems it moves even more than Cancelara's Domane; you think has anything to do with the Zertz elastomers?


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## roadworthy (Nov 11, 2011)

dcgriz said:


> I am wondering if any of you who happen to ride any of the Roubaix SL3s with the carbon seatpost, realize how much the post oscillates while riding. I have a 58 Pro SL3 with about 7" to 8" inches of seatpost showing and this thing moves. I took a video on the trainer the other day checking on Q-factors and the like and that's when I realized it.
> It seems it moves even more than Cancelara's Domane; *you think has anything to do with the Zertz elastomers?*


Not per se. Think of the Zertz as a very compliant rubber based plastic aka elastomer that is there is quell high frequency vibration. It is almost an addendum but not the basis for structure as it isn't very strong. It has a very low flex mod and has low yield strength. What Specialized uses with their rear triangle, front fork and seat post is high modulus aka high yield strength carbon fiber. By design intent, they posture the seat stays, front fork and seat post to flex quite a bit under load. Judicious design of high yield strength carbon sections..for example the rear Roubaix seat stay acts almost as a fixed hinge...allows higher deflection without fracture...in other words areas of the frame will elastically deform a fair amount in vertical direction and not break and return to original state unloaded. I noticed the same thing when riding my Roubaix SL3. I read one review of the bike that said that the seat post is integral to the overall ride quality of the Roubaix. I am a believer now having ridden the bike for a month or so. By contrast I rode a Thomson post on my last bike and it was truck axle stiff.

You mentioned the new Trek which has a mechnical pivot at the seat post. I read a review of the bike and there was a quote relative to increase in deflection. Do you know how it compares to the Roubaix...as you mentioned the Roubaix displaces more?
Lastly...no doubt you running so much seat post...I run about 7-8" as well on my 58cm Roubaix contributes to the overall flexibility of the post...which is affected by rider weight and of course how long the post is cantilevered away from the seat clamp.


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## dcgriz (Feb 13, 2011)

It seems to me that the free movement of the seatpost does a lot more to absorb road vibration than any fixed frame component like the seatstays ever would. However, it also absorbs energy that otherwise would have been transfered to the pedals. So no free lunch here, just a trade off. Yes, the seatstays move elastically but the travel is on a very finite module and is more due to the change in plane of direction (right by the Zertz gizmos) than on anything else. Flexing of the front fork/assembly I believe is more of a detriment than merit and I am not so sure its the case with the SL3 with the oversized HT and the like.
I dont know how the Domane seatpost travel compares to the Specialized, to answer your question. When I read the Trek article and viewed the video clip, I first chuckled and then I wanted to congratulate that marketing guy who packaged such a simple concept, its effects available for free when you buy a carbon post, into an engineering solution with pivot bearings and everything. I wonder if a spring loaded saddle with travel stops would have a similar effect?


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## roadworthy (Nov 11, 2011)

dcgriz said:


> It seems to me that the free movement of the seatpost does a lot more to absorb road vibration than any fixed frame component like the seatstays ever would. However, it also absorbs energy that otherwise would have been transfered to the pedals. So no free lunch here, just a trade off. Yes, the seatstays move elastically but the travel is on a very finite module and is more due to the change in plane of direction (right by the Zertz gizmos) than on anything else. Flexing of the front fork/assembly I believe is more of a detriment than merit and I am not so sure its the case with the SL3 with the oversized HT and the like.
> I dont know how the Domane seatpost travel compares to the Specialized, to answer your question. When I read the Trek article and viewed the video clip, I first chuckled and then I wanted to congratulate that marketing guy who packaged such a simple concept, its effects available for free when you buy a carbon post, into an engineering solution with pivot bearings and everything. I wonder if a spring loaded saddle with travel stops would have a similar effect?


Don't know your background but you have to be careful about sweeping inferences about the design without seeing the analysis. Vertical frame compliance is a system and no doubt computer modeled dynamically. The seat stays, rear fork bridge and proximity of the bridge to seat clamp which is longer than on conventional bikes, seat post and even tapered seat tube all are engineered to a given contribution of force/defection. Pretty impossible to speculate on the respective contribution of each without witnessing the modeling and incremental modeling...which was likely iterated and physically tested in hundreds of configurations to achieve the desired balance. Angles matter a a lot as well in addition to material properties and section modulus.
A hugely complex structure that is carefully engineered that functions/elasically deforms under load as a 'system'. 

As to your comments about a flexible seat post robbing pedal power. Not so either. If you ride behind a top rider say in a fast group ride or pace line, you will notice his weight it barely on the saddle if he or she is laying down the watts. The saddle is called a saddle because it isn't a seat...its a perch. Its also the reason that strong riders complain less about saddle discomfort. They put less weight on it due to higher pedal forces. Pressing on the pedals removes ride weight from the saddle. Under light pedal pressure, you aren't riding hard or fast and so seat post flexibility doesn't matter anyway. A flexible post doesn't rob watts from the pedals. If too flexible it could be disconcerting on rough roads but I don't feel this to be the case. Specialized really did an amazing job with the Roubaix.


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## dcgriz (Feb 13, 2011)

roadworthy said:


> Don't know your background but you have to be careful about sweeping inferences about the design without seeing the analysis. Vertical frame compliance is a system and no doubt computer modeled dynamically. The seat stays, rear fork bridge and proximity of the bridge to seat clamp which is longer than on conventional bikes, seat post and even tapered seat tube all are engineered to a given contribution of force/defection. Pretty impossible to speculate on the respective contribution of each without witnessing the modeling and incremental modeling...which was likely iterated and physically tested in hundreds of configurations to achieve the desired balance. Angles matter a a lot as well in addition to material properties and section modulus.
> A hugely complex structure that is carefully engineered that functions/elasically deforms under load as a 'system'.
> 
> As to your comments about a flexible seat post robbing pedal power. Not so either. If you ride behind a top rider say in a fast group ride or pace line, you will notice his weight it barely on the saddle if he or she is laying down the watts. The saddle is called a saddle because it isn't a seat...its a perch. Its also the reason that strong riders complain less about saddle discomfort. They put less weight on it due to higher pedal forces. Pressing on the pedals removes ride weight from the saddle. Under light pedal pressure, you aren't riding hard or fast and so seat post flexibility doesn't matter anyway. A flexible post doesn't rob watts from the pedals. If too flexible it could be disconcerting on rough roads but I don't feel this to be the case. Specialized really did an amazing job with the Roubaix.


My background.....let's say I'm a scientist as a lot of people on this board. I agree with the general statement about computational analysis and dynamic modeling. However, at the end of the day, the bicycle frame remains a truss and a very simplistic design at that. Furthermore, the engine that powers it, is an amazing machine. Amazing in the sense that is dynamically adaptive to quite a variety of variables with the same range of results. The point here is that the perceived reaction to the human body of a mechanical/kinetic/etc etc action may not be as significant as laboratory tests would like it to be. This is where marketing crosses the lines with science.
Don't think for a second I am discounting the importance of analysis, I am merely questioning the perspective.

I see the logic in your statement about the saddle and the force on the pedals when the rider is laying down the watts, as you said. I believe there are additional forces than you describe but let's say the significant ones are as you stated. What happens when he is not all out but he is at 75%, 80%, 85%, etc. etc.? The athlete who just won the Roubaix race spent 5.5 hrs and some change on the bike. You think all this time was spent on his quads? Think about it. 

We can neither create nor destroy energy; we can transform it and direct it, until now at least. If you are on the pedals, most of your energy goes there. If you are supporting yourself on the seat post, some of it goes there as well. There are only three places it could go anyway. The real benefit out of all of this is by having this relief, it makes the ride more tolerable which in turn makes it less taxing to the body which in turn allows it to apply it longer. This synergy is what the end result is trying to be.

I do like the Roubaix, I truly believe Specialized did a fine job with them and I own two to prove it. I also believe that Specialized's contribution to the cycling community was the upright posture the Roubaix formally introduced that made cycling fun for the regular rider, weekend warrior and amateur racer. After all they created the Plush concept. I think you will disagree with me on this but I do also believe that the Zertz elastomers are a marketing gimmick, arguably a necessary one to help make a distinction from a lot of other choices. All manufacturers have them in various forms, it's how the game is played.

I enjoyed chatting with you....🍻


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## msg98 (Oct 27, 2011)

dcgriz said:


> I am wondering if any of you who happen to ride any of the Roubaix SL3s with the carbon seatpost, realize how much the post oscillates while riding. I have a 58 Pro SL3 with about 7" to 8" inches of seatpost showing and this thing moves. I took a video on the trainer the other day checking on Q-factors and the like and that's when I realized it.
> It seems it moves even more than Cancelara's Domane; you think has anything to do with the Zertz elastomers?




can you post the video? quite curious.


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## dcgriz (Feb 13, 2011)

msg98 said:


> can you post the video? quite curious.


Unfortunately it has been taken on media that does not allow an easy transfer to a computer. If you watch the Trek video, towards the middle, they show how the post behaves under force from a kinetic machine. That action is quite similar to what I observed. I am sure the action has a lot to do with my weight, power and the length of the exposed post so results may differ.


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## Scott in MD (Jun 24, 2008)

"I do also believe that the Zertz elastomers are a marketing gimmick".

Maybe. Up to now. But the BIG open-end zertz on the SL4 (per the pics) and other new bikes like the Volagi and the Domane .... well seems to me like this is heading towards a real suspension design ... which I do not want. At least I think I don't want.

I might, maybe, possibly ride just a few times in my life on a course like Boonen on Paris-Roubaix ... so I don't want a "full suspension" bike like a Domane for my regular roadie. I want a fast, crisp, relatively lightweight, but also compliant and smooth bike with a geometry that fits me. 

That's why I'm going to be in the market for an Roubaix SL3 in the fall once the SL4's hit the market.

What kind of deal do you think I can get on an S-Works frame set?!?!

(Then again I was a late adopter for disc brakes on my trail bike...)


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## dcgriz (Feb 13, 2011)

Scott in MD said:


> "I do also believe that the Zertz elastomers are a marketing gimmick".
> 
> Maybe. Up to now. But the BIG open-end zertz on the SL4 (per the pics) and other new bikes like the Volagi and the Domane .... well seems to me like this is heading towards a real suspension design ... which I do not want. At least I think I don't want.
> 
> ...


Two of the bikes in my small stable are a 2009 Roubaix Elite (pre-SL, 7r carbon) and a 2011 Roubaix Pro SL3 (10r carbon). The Zertz inserts on the 2009 are true inserts in the sense that the frame at the seatstays splits to two distinctly separate legs and the Zertz fills the gap between them. When you look at the seat stay you see the front and the back of the insert. It caught my eye when I first saw it; quite impressive. 

The 2011 SL3 which by the way is a heck of a bike, shows a different design at the seatstays. They do maintain the same overall shape and direction but no longer split to two legs. What used to be the opening for the Zertz to be inserted is now completely closed and is no longer an opening, it has become a recession. The Zertz is now surface applied and secured by two screws. That juncture obviously flexes and that's why the screws vs. just adhesive. Additionally, the Zertz at the seat post is now about 30% in size of what used to be on the 2009.

My hunch is that the driving forces behind these developments are stemming out of carbon frame manufacturing efficiencies. The 2009 seat stays being a more intricate design maybe took more to make and maybe they were more prone to breakage? The 2011 design appears to be significantly simpler. Although the Zertz design and attachment have been changing around, what has remained the same is the overall seat stay design with the "hinge" point in the middle (where the Zertz is applied). In my belief, it's the "hinge" that is doing most of the dampening work; the Zertz maybe contributes some structurally/elastically but it's main contribution, I think, is visual. Both bikes are equally comfortable, at least as perceived by my body, although the Specialized lab tests showed a definite improvement on the SL3. 

The 2013 design from what I see from the pics, continues with the same design .approach. The seat stays maintain the same overall design (hinge et all) but now the Zertz looks like a clip-on that wraps around the "hinge". Interestingly enough the offset on the seat post its now a vibration dampening device as well. That looks smart, I have to see it in person. See, I did bite!

Referring to your discussion on future developments. It seems to me that the Tarmac and the Roubaix will be further defined by purpose. The Tarmac SL4 will be the aggressive geometry bike, the Tarmac SL3 the tamer racer, the Roubaix SL4 for the rougher tarmac??? and the Roubaix SL3 the long wheelbase comfortable cruiser. Something for each and every one of us.

I don't know what kind of deal you could get on a S-Works. They are around though and some will be left hanging come early winter. Personally, unless I was a featherweight which I am not, I would not pay the extra $1k for the S-Works. I would get the SL3 frameset and put the extra money building it right and on the Di2.


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## roadworthy (Nov 11, 2011)

dcgriz said:


> My background.....let's say I'm a scientist as a lot of people on this board. I agree with the general statement about computational analysis and dynamic modeling. However, at the end of the day,* the bicycle frame remains a truss and a very simplistic design at that*. Furthermore, the engine that powers it, is an amazing machine. Amazing in the sense that is dynamically adaptive to quite a variety of variables with the same range of results. The point here is that the perceived reaction to the human body of a mechanical/kinetic/etc etc action may not be as significant as laboratory tests would like it to be. This is where marketing crosses the lines with science.
> Don't think for a second I am discounting the importance of analysis, I am merely questioning the perspective.
> 
> I see the logic in your statement about the saddle and the force on the pedals when the rider is laying down the watts, as you said. I believe there are additional forces than you describe but let's say the significant ones are as you stated. What happens when he is not all out but he is at 75%, 80%, 85%, etc. etc.? The athlete who just won the Roubaix race spent 5.5 hrs and some change on the bike. You think all this time was spent on his quads? Think about it.
> ...


Hi dcgriz,
You make many good points of course and you and I can relate to one another because of our backgrounds.
I will tell you where I fundamentally disagree however with what you write which I have embellished in bold above. I believe your assertion that a bike frame is a simple truss is simply untrue. I have done a lot of computer modeling of complex surfaces. A bike frame and Roubaix frame in particular which is basically all complex surfaces is far from simple....quite the contrary. I will leave you with a simple analogy to support this. I have owned 100 road bikes over my lifetime and ridden probably a couple hundred more. I have never ridden a bike that has the combination of lateral stiffness and vertical deflection aka comfort that the Roubaix has. The Roubaix not only looks radically different because of its complex surfaces...aka every tube section is tapered and most are assymmetric...but no bike I have ridden compares...modern or past. If it were a simple forumula, it would be out there in abundance...but it isn't. The Roubaix SL3 is a watershed bike in design. If you have done CAD analysis including FEA and dynamic modeling...you know the drill. Design and test...repeatedly. Computer models are only a facsimile. The recipe of the new Roubaix and what looks to be the next gen Roubaix is unique. If all the complex sections that comprise the Roubaix were simple, more bikes would be on the market with this tremendous performance level.
Cheers.


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## dcgriz (Feb 13, 2011)

@ roadworthy 

I admire your passion about your Roubaix. I can not say I agree with several of your viewpoints or deductions but I do concur with the end result which is that the SL3 is beautifully executed.
Ride on.....


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## roadworthy (Nov 11, 2011)

dcgriz said:


> @ roadworthy
> 
> I admire your passion about your Roubaix. I can not say I agree with several of your viewpoints or deductions but I do concur with the end result which is that the SL3 is beautifully executed.
> Ride on.....


I'm a bike freak with a technical background is all. Bikes range A-Z in terms of performance even made from the same material. There is nothing simple about bike design or there would be more good bikes out there. Historically an uber stiff racing frame would rattle your teeth. This doesn't have to happen as Specialized has proven. An aluminum bike say like the new CAAD 10 can be engineered to feel almost as good as many mid range carbon road bikes out there and better than previous gen high end carbon bikes like the Madone...with completely different material properties. Previous CAAD bikes would make a grown man cry riding aggressively over rough roads. New bikes are made out of the same material...and the magic and sweat is in achieving the correct section modulus throughout the entire bike. It isn't simple...its hard to achieve. This is done through computer modeling, prototyping and exhaustive physical testing. The bar continues to be raised and we are all the better for it.
Cheers.


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## Scott in MD (Jun 24, 2008)

Dogriz, yep to all, especially that there is not a grand worth of difference in the 2012 Pro and S-works frameset. Except the SL3 pro frameset is integrated/threaded bottom bracket, not BB30, and I like the BB30 design, especially for the extra heel clearance. I imagine the 2013 SL3 Expert and SL3 Pro and Pro frameset will all be BB30 (or PF30) next year, making some good deals available on the '12 S-works frame if the '13 S-works is an SL4.


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## roadworthy (Nov 11, 2011)

Scott in MD said:


> Dogriz, yep to all, especially that there is not a grand worth of difference in the 2012 Pro and S-works frameset. *Except the SL3 pro frameset is integrated/threaded bottom bracket, not BB30,* and I like the BB30 design, especially for the extra heel clearance. I imagine the 2013 SL3 Expert and SL3 Pro and Pro frameset will all be BB30 (or PF30) next year, making some good deals available on the '12 S-works frame if the '13 S-works is an SL4.


Not true...in bold above. Frameset only is available in threaded BB...but Robaix SL3 Pro 'complete bike' sold by Specialized _IS_ BB30. Why do they do this? Because the Specialized crank sold on the complete bike is only compatible with BB30.


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## Scott in MD (Jun 24, 2008)

How can be "not true" if we said exactly same thing?:

Me - "the SL3 pro frameset is integrated/threaded bottom bracket, not BB30"
You - "Frameset only is available in threaded BB, but ..."

I thought you were switching to green tea? 

(OK, yes, you are right (and I was silent) on the complete bike BB30.)

Next year's Pro frameset and probably even the Expert bike (with an FSA crank)  will be BB30, I think...


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## roadworthy (Nov 11, 2011)

Scott in MD said:


> How can be "not true" if we said exactly same thing?:
> 
> Me - "the SL3 pro frameset is integrated/threaded bottom bracket, not BB30"
> You - "Frameset only is available in threaded BB, but ..."
> ...


The Roubaix Pro is sold in threaded BB, BB30 and even Specialized version of PF30 on their S-works Roubaix.
They make the Roubaix SL3 frameset in all three BB configurations.
Forgive me for correcting you, but no doubt you get that a lot. :thumbsup:


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## shokhead (Dec 17, 2002)

roadworthy said:


> Nothing has stopped you from carrying on. In any event, you are amusing.
> 
> I think you need a primer so will break it down for you because your trite references to commonly understood tire pressure tradeoffs are forgive me, a bit boring.
> 
> ...


I ride a Roubaix. 5psi difference either way I notice.


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## roadworthy (Nov 11, 2011)

shokhead said:


> I ride a Roubaix. 5psi difference either way I notice.


Depends what kind of roads you ride. On a smooth road, I challenge your assertion.
Lance Armstrong is said to be able to feel a 1mm change in his bike set up. Different people are more or less sensitive to bike changes.


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## Chris-X (Aug 4, 2011)

roadworthy said:


> Depends what kind of roads you ride. On a smooth road, I challenge your assertion.
> *Lance Armstrong* is said to be able to feel a 1mm change in his bike set up. Different people are more or less sensitive to bike changes.


He talks nonsense because he knows his competitors read it and it puts thoughts in their heads.

Ben Hogan was asked by Ben Crenshaw how he put so much spin on the ball and Hogan said he hit it on the third groove from the bottom.

This was in a book called "The Hogan Mystique"


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## PJ352 (Dec 5, 2007)

shokhead said:


> I ride a Roubaix. 5psi difference either way I notice.





roadworthy said:


> *Depends what kind of roads you ride*. On a smooth road, I challenge your assertion.
> Lance Armstrong is said to be able to feel a 1mm change in his bike set up. Different people are more or less sensitive to bike changes.


Given your previous stand that the inherent attributes of the Roubaix frame negates the need to taper (down) tire pressures to preserve ride quality, Unless you're now reversing your position, I find this response confusing. 

Road surface or PSI shouldn't be relevant if your previous arguments hold true.


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## PJ352 (Dec 5, 2007)

Chris-X said:


> He talks nonsense...


I agree. When it comes to knowledge of bike fit, Lemond runs rings around Armstrong. Just like some racers, the latter may know what _feels_ right, but hasn't a clue how to achieve it. That's what their fitters are for.


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## Chris-X (Aug 4, 2011)

The tires, wheels and pressures of Paris-Roubaix

Ok, back to common sense, reality, useful info, seeing and feeling what's right in front of your face, seeing things the old fashioned way, things are more or less the way they seem.

Boonen and Chavenel both riding pressures less than 65psi on front and rear. The Roubaix allows clearance for 28mm tires, why go smaller?


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## Stumpjumper FSR (Aug 6, 2006)

Chris-X said:


> The tires, wheels and pressures of Paris-Roubaix
> 
> Ok, back to common sense, reality, useful info, seeing and feeling what's right in front of your face, seeing things the old fashioned way, things are more or less the way they seem.
> 
> Boonen and Chavenel both riding pressures less than 65psi on front and rear. *The **Roubaix allows clearance for 28mm tires, why go smaller*?


If I were riding on cobbles I'd agree with you but I'm not, I personally prefer 23c tires on my SL3 over 25c...but hey thats me...of course I don't pump them up to 130 psi


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## Chris-X (Aug 4, 2011)

*I'm sometimes into passive*



Stumpjumper FSR said:


> If I were riding on cobbles I'd agree with you but I'm not, I personally prefer 23c tires on my SL3 over 25c...but hey thats me...of course I don't pump them up to 130 psi


aggressive fun (no, just joking) so I'm looking for noisy knobby tires for my dumpster junk bike, to annoy people when I come up on them and drop them.

Might get my world ranking down from 1479 into the 12 or 13 hundreds!:thumbsup:

Seriously, the Roubaix rides nice, but so does my kg 381.

Would I drive a late 70's or early 80's Porsche 911? Yes. Is an Audi S 4 a nicer car? Yes..Does it matter??? uh no, not really.

BTW, I hope all of you are fortunate enough to get a nice ride in today and smell the roses...


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## shokhead (Dec 17, 2002)

Some of these bike might be killer good on cobbles but most of us don't ride cobbles. Just because they work good on big old cobble stones doesn't mean they will on chip and seal. Big difference between the 2. Kinda funny cobbles is always used when they are trying to sell these bigs to us that don't ride on that stuff.


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## PJ352 (Dec 5, 2007)

shokhead said:


> Some of these bike might be killer good on cobbles but most of us don't ride cobbles. Just because they work good on big old cobble stones doesn't mean they will on chip and seal. Big difference between the 2. *Kinda funny cobbles is always used when they are trying to sell these bigs to us that don't ride on that stuff.*


Agree, but that's no different than selling the Venge to recreational cyclists that'll probably not reap the (aero) benefits because they'll seldom crack 27 MPH (cruising). Or, selling BB30 (or similar) even though few and far between are able to flex standard BB's. And even when the can, they're not _really_ sure where the source of the flex is. Or, 11 speed drivetrains. 

The list is long, and consumers keep buying into the hype (literally). But then, that's the manufacturers goal.


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## shokhead (Dec 17, 2002)

If I bought one it would more about the geo then what it does on cobbles.


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## Chris-X (Aug 4, 2011)

shokhead said:


> Some of these bike might be killer good on cobbles but most of us don't ride cobbles. Just because they work good on big old cobble stones doesn't mean they will on chip and seal.* Big difference between the 2*. Kinda funny cobbles is always used when they are trying to sell these bigs to us that don't ride on that stuff.


What is that difference?


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## dcorn (Sep 1, 2011)

I kinda doubt Spesh went so far as to tune the zertz inserts to only dampen the resonant frequency of the cobblestones in France, where any other vibration frequency will cause the bike to catastrophically fail. 

I'd say the bike would do just fine riding on rough, cracked roads or on a MUT with cracks and expansion joints here in the US .


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## jinnjia (Jun 12, 2010)

Should I be concerned about the "zerts insert"'s longevity ? 
Afterall it is made out of some rubbert materials, will the life span eventually be diminishi as time goes by ? Say after 10 or 15 years ?

Kind of reminded me of those shock dampener on the tennis racquet, you have to replace them every once awhile to retain the full effect. 

I dont suppose the zerts inserts can be replaceable ?


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## shokhead (Dec 17, 2002)

Do you keep your bike for 15 years?


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## purdyd (Jun 18, 2010)

dcorn said:


> I kinda doubt Spesh went so far as to tune the zertz inserts to only dampen the resonant frequency of the cobblestones in France, where any other vibration frequency will cause the bike to catastrophically fail.
> 
> I'd say the bike would do just fine riding on rough, cracked roads or on a MUT with cracks and expansion joints here in the US .


things, like bikes, guitar strings, etc tend to have resonant frequencies so when you strike them, they will vibrate

things like zertz, will absorb some of that vibration so after the bike is struck, it won't 'ring' as much

so you would tune the zertz to the frame, rather than the road, at least in my humble opinion


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## shokhead (Dec 17, 2002)

dcorn said:


> I kinda doubt Spesh went so far as to tune the zertz inserts to only dampen the resonant frequency of the cobblestones in France, where any other vibration frequency will cause the bike to catastrophically fail.
> 
> I'd say the bike would do just fine riding on rough, cracked roads or on a MUT with cracks and expansion joints here in the US .


Then you haven't read reviews that said it did the best of bikes tested on stones but not on everyday chip and seal. It didn't suck but it wasn't the best at it tested. Really,prob make no difference.


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## roadworthy (Nov 11, 2011)

shokhead said:


> Then you haven't read reviews that said it did the best of bikes tested on stones but not on everyday chip and seal. It didn't suck but it wasn't the best at it tested. Really,prob make no difference.


Do you own a Roubaix SL3? I do. I have read a number of reviews. Ride quality is outstanding and why I built one up. I would say most in America don't ride cobblestones. I didn't buy the bike to ride cobblestones. I bought it to ride crappy midwestern roads which are broken surfaces and have never ridden a smoother riding bike. 
Please post the article you reference. Would love to see what bike has a better overall ride quality than the Roubaix SL3 on chip and seal.


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## shokhead (Dec 17, 2002)

roadworthy said:


> Do you own a Roubaix SL3? I do. I have read a number of reviews. Ride quality is outstanding and why I built one up. I would say most in America don't ride cobblestones. I didn't buy the bike to ride cobblestones. I bought it to ride crappy midwestern roads which are broken surfaces and have never ridden a smoother riding bike.
> Please post the article you reference. Would love to see what bike has a better overall ride quality than the Roubaix SL3 on chip and seal.


I only have a 05 Roubaix Comp and I think it was velonews endurance bikes put to the test on the cobbles and in the lab that did it between the Roubaix, Bianchi Infinito, C Synapse and Lapierre's Sensium . As I remember the Roubax was best on cobbles and second best on chip and seal.


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## jinnjia (Jun 12, 2010)

shokhead said:


> Do you keep your bike for 15 years?


I sure hope so.....
Even if I am not I sure would like to have the peace in mind knowing some unreplaceable part will not run out on me.


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## shokhead (Dec 17, 2002)

Well mines an 05 and they are still there, unchanged.


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## roadworthy (Nov 11, 2011)

shokhead said:


> Well mines an 05 and they are still there, unchanged.


What's unchanged?
PS: Nobody can predict the longevity of anything including the bicycle company Specialized. The Zertz are elastomers...look to be easily replicated if not from the OEM than in the aftermarket...latest version are mechnically fastened and are in compression and not in tension and likely won't fail in that time period. There are a few 15 year old carbon frames out there...very early ones but depends if you want to ride a 15 year old carbon frame aggressively down hill at 40mph. I am not sure I do...but don't believe there is a finite correlation between age and pre-disposition for carbon to fail. By all indications carbon has very good fatigue life but carbon failures can be due to the layup and design itself...aka Cervelo's recall on carbon fork failures resulting in a purported cyclists' death.


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## shokhead (Dec 17, 2002)

roadworthy said:


> What's unchanged?
> PS: Nobody can predict the longevity of anything including the bicycle company Specialized. The Zertz are elastomers...look to be easily replicated if not from the OEM than in the aftermarket...latest version are mechnically fastened and are in compression and not in tension and likely won't fail in that time period. There are a few 15 year old carbon frames out there...very early ones but depends if you want to ride a 15 year old carbon frame aggressively down hill at 40mph. I am not sure I do...but don't believe there is a finite correlation between age and pre-disposition for carbon to fail. By all indications carbon has very good fatigue life but carbon failures can be due to the layup and design itself...aka Cervelo's recall on carbon fork failures resulting in a purported cyclists' death.


The zerts are unchanged from what I can tell. Rides the same, the look the same. That's all I can go by. Are you looking for somehing to not agree on? someone asked about "zerts insert"'s longevity and I just said mine is an 05 and they are fine.


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## roadworthy (Nov 11, 2011)

shokhead said:


> The zerts are unchanged from what I can tell. Rides the same, the look the same. That's all I can go by. Are you looking for somehing to not agree on? someone asked about "zerts insert"'s longevity and I just said mine is an 05 and they are fine.


The Zertz changed from your gen to the SL3. If you read reviews of the SL3 bike... detail is provided about changes compared to the SL2...a very different bike...redesigned front to back. Zertz on the SL3 are mechanically fastened to front fork and rear seat stays via torx screws for easy replacement. Rear seat stays deflect considerably more than the previous generation Roubaixs and yet the bike is much stiffer in head tube connection, downtube and BB...giving the bike a completely different feel. Cancellara remarked the SL3 Roubaix is as stiff as any Tarmac he raced. The SL2 and early Roubaixs by contrast had quite a bit of flex. The Zertz on the SL4 Roubaix appear to change even more.


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## shokhead (Dec 17, 2002)

200 pounds and haven't felt flex yet but maybe I've been lucky.


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## Chris-X (Aug 4, 2011)

roadworthy said:


> The Zertz changed from your gen to the SL3. *If you read reviews of the SL3 bike... detail is provided about changes compared to the SL2...a very different bike...redesigned front to back. Zertz on the SL3 are mechanically fastened to front fork and rear seat stays via torx screws for easy replacement. Rear seat stays deflect considerably more than the previous generation Roubaixs and yet the bike is much stiffer in head tube connection, downtube and BB...giving the bike a completely different feel. *Cancellara remarked the SL3 Roubaix is as stiff as any Tarmac he raced. The SL2 and early Roubaixs by contrast had quite a bit of flex. The Zertz on the SL4 Roubaix appear to change even more.


http://m.bikeradar.com/gear/categor...view-specialized-roubaix-s-works-sl2-10-35416

http://m.bikeradar.com/news/article...review-tarmac-sl3-secteur-roubaix-shiv-22207/



But what about drivetrain stiffness?

"The SL2 bottom bracket rigidity had reached a point where even top pros like [Fabian] Cancellara and [Tom] Boonen can't discern a difference any more," said Specialized marketing man Ben Capron. As such, Specialized chose to focus on the other ends of the frame that would yield tangible improvements in handling precision.



We can't confirm Specialized's assertion that the new Tarmac SL3 offers the highest stiffness-to-weight ratio among all the major players (and it admits that it hasn't tested every frame on the market) *but based on our experience on the SL2 – and now our brief taste test of the SL3 – any improvement in that area would be quite an accomplishment.*

Roubaix and Secteur: more value and performance through rest of range

The Roubaix chassis range will carry into the 2010 model year unchanged but Specialized will add a less expensive variant called Secteur that uses identical geometry but in aluminium. 


The Specialized Roubaix platform will carry over into 2010 essentially unchanged.

http://m.bikeradar.com/news/article/specialized-roubaix-sl3-first-ride-review-27771/

On top of better vibration damping, Specialized claim a 7.5 percent increase in vertical compliance (measured in deflection – mm/kN) over the previous Roubaix, along with a 20 percent improvement in its torsional-stiffness-to-weight ratio.


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