# ZIPP 303FCs or 404FCs



## martinot (Aug 14, 2009)

Cannot decide which would suit me better: 303s or 404s tubulars. I appreciate any food for thoughts.

The bike will be S-Works Tarmac SL4 with new Red (I realize that 303 tubies might not even fit into this frame based on ZIPP notes but ...)
The wheels will be primarily used for racing (not sure about using them for crits). I race about 50/50 flat/roller and hilly courses. I often escape and work with just few riders, am semi-decent in sprints, and mange to do well in longer suffering hilly courses.
I race currently on 46mm el cheepo carbon tubulars (complete bike weight with wheels and pedals - 14.6 lbs)

303s are certainly lighter than 440s (some 100 grams) but 404s might shave off some watts in escapes and lead-outs; will they?

Ideas?


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## martinot (Aug 14, 2009)

404s are 7% heavier than 303s - .2 lbs. If aero effect diff between the two is marginal then I'd rather have lighter hoops - 303s. Am I thinking wrong?


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## antihero77 (Jul 26, 2011)

It's shown on zipps site that between the 303 and 404 is marginal gains
Personally I would go 404


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## cxwrench (Nov 9, 2004)

the 303's are insanely strong, very good impact resistance...if that matters in your decision. i'd also use 25mm tires on them if they were mine.


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## QQUIKM3 (Apr 20, 2008)

*Depends..*



martinot said:


> Am I thinking wrong?


For flat to rolling terrain, the 404s would be the smart choice. The 303s aren't deep enough to really be aero anyway. You need at least a 50mm deep wheel to see any appreciable benefit.


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## QQUIKM3 (Apr 20, 2008)

*Curious.. .*



cxwrench said:


> the 303's are insanely strong. .


Are they stronger than the 404s? If not, the 404 makes sense IMO. Once the wheel has spun up, the extra mass is out of the equation and aerodynamics takes over.


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## asgelle (Apr 21, 2003)

QQUIKM3 said:


> For flat to rolling terrain, the 404s would be the smart choice. The 303s aren't deep enough to really be aero anyway. You need at least a 50mm deep wheel to see any appreciable benefit.


Simply put, you don't know what you're talking about. Wind tunnel data shows a reduction in drag for rims as shallow as 25 mm.

The importance of the benefit is specific to the individual so there's no point using words like appreciable, significant, meaningful, or negligible. Everyone has to look at the data and decide what wheel best fits his or her needs.


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## jsedlak (Jun 17, 2008)

martinot said:


> Cannot decide which would suit me better: 303s or 404s tubulars. I appreciate any food for thoughts.
> 
> *The bike will be S-Works Tarmac SL4 with new Red (I realize that 303 tubies might not even fit into this frame based on ZIPP notes but ...)*
> 
> ...


There are stock SL4s and Venges that come with 303s/404s. The fitment is fine!


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## cwg_at_opc (Oct 20, 2005)

303 front/404 rear.


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## QQUIKM3 (Apr 20, 2008)

*I didn't say they weren't aero. .*



asgelle said:


> Simply put, you don't know what you're talking about. Wind tunnel data shows a reduction in drag for rims as shallow as 25 mm.


I was implying that if he's looking at 303 versus the 404 the OP would get more aerodynamic benefits out of the 404s. Sorry if English is your second language.


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## Urb (Jul 19, 2010)

QQUIKM3 said:


> I was implying that if he's looking at 303 versus the 404 the OP would get more aerodynamic benefits out of the 404s. Sorry if English is your second language.


The way I read it was you do not think there is adequate aero benefit in the 303's. However in reality 303's and 404's share similar aero benefits.


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## ergott (Feb 26, 2006)

QQUIKM3 said:


> The 303s aren't deep enough to really be aero anyway. You need at least a 50mm deep wheel to see any appreciable benefit.
> 
> 
> I was implying that if he's looking at 303 versus the 404 the OP would get more aerodynamic benefits out of the 404s. Sorry if English is your second language.


Sorry, but that's not what you wrote.


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## martinot (Aug 14, 2009)

asgelle said:


> ....
> Everyone has to look at the data and decide what wheel best fits his or her needs.


Can you give some ideas as to what data to look at and how to analyze it to come to the best conclusion?

Huh, looks like it would be best to buy two sets: 303s and 404s  or as cwg_at_opc suggests get a 303/404 combo - SMART setup 

By looking at the latest classics + ToR + ToT I'd say that 303s would be the choice. I have not seen anyone on anything deep (50mm being probably the deepest). 58mm might be an overkill for anything but flats only. But please keep posting the opinions and suggestions. Much appreciated.


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## ergott (Feb 26, 2006)

I prefer to roll on more aero wheels. The added rim weight feels better to me.

I ride mostly flat and rolling terrain. The climbs are shorter, but steep enough. If I were deciding between the two I'd get the 404s. They aren't exactly heavy. It also depends on the speeds you ride. If you can maintain a 20+ tempo for extended periods the heavier, more aero wheels feel better under you.

That's me speaking outside the numbers.


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## martinot (Aug 14, 2009)

ergott said:


> I prefer to roll on more aero wheels. The added rim weight feels better to me.
> 
> I ride mostly flat and rolling terrain. The climbs are shorter, but steep enough. If I were deciding between the two I'd get the 404s. They aren't exactly heavy. It also depends on the speeds you ride. If you can maintain a 20+ tempo for extended periods the heavier, more aero wheels feel better under you.
> 
> That's me speaking outside the numbers.


In such case I think the best thing would be to test ride them for some time and get a feel for myself (fortunately few shops rent them around here). Thx guys!!!


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## cwg_at_opc (Oct 20, 2005)

as i have both an aero 'regular' road bike(cervelo s1) and a tri-bike, i like deep wheels - i'm running an older, non-dimpled version of the 404(it's the Real Design Supersonic 60, Al rim, structural carbon fairing bonded, clincher.)

given a choice(and the budget) i'd even go as far as a 404 front AND an 808 rear.

the benefit to the 303/404 combo is you still get the aero advantages AND the lower weight/mass up front AND less surface area for cross winds to blow you around.
when in doubt, always go deeper in back to move the center-of-pressure away from the steering axis.




martinot said:


> Can you give some ideas as to what data to look at and how to analyze it to come to the best conclusion?
> 
> Huh, looks like it would be best to buy two sets: 303s and 404s  or as cwg_at_opc suggests get a 303/404 combo - SMART setup
> 
> By looking at the latest classics + ToR + ToT I'd say that 303s would be the choice. I have not seen anyone on anything deep (50mm being probably the deepest). 58mm might be an overkill for anything but flats only. But please keep posting the opinions and suggestions. Much appreciated.


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## looigi (Nov 24, 2010)

cwg_at_opc said:


> 303 front/404 rear.


That'd be better for handling in crosswinds, but 404 front/303 rear would be more aero as the front wheel has more of an effect due to being in clean air...FWIW.


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## cwg_at_opc (Oct 20, 2005)

looigi said:


> That'd be better for handling in crosswinds, but 404 front/303 rear would be more aero as the front wheel has more of an effect due to being in clean air...FWIW.


see my reply above. also, if that were true, then the new Enve SES would be 4.3, 7.6 instead of 3.4 and 6.7.


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## Keoki (Feb 13, 2012)

looigi said:


> That'd be better for handling in crosswinds, but 404 front/303 rear would be more aero as the front wheel has more of an effect due to being in clean air...FWIW.


The guys at Zipp told me the same thing you've just did.


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## Pharmerbob (Jun 27, 2011)

One thing to remember is that according to Zipp's website, the 303 will not fit on the rear on an SL-4 Tarmac


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## FrankDaTank (May 30, 2011)

Go the 404's.
I have Zipp 808FC tubs for racing in flat and rolling courses and would recommend them highly. Research has shown that aero wins over any weight advantage in wheels until you are on a steep climb (can't remember exactly how steep though). so unless the race is all climbing you are better off over all with more aero wheels. Even in a pack the advantages are there. 
Another lot of data showed that the in the yaw angle of 15-22 degrees, 808FC's actually have a negative resistance value; in other words they propel you forwards. It sounds crazy but I must say I have noticed a lift occasionally when rolling in an echelon during a race.

The article is here pg 96
http://www.tour-qtr.com/epaper_4_2011


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## cxwrench (Nov 9, 2004)

QQUIKM3 said:


> Are they stronger than the 404s? If not, the 404 makes sense IMO. Once the wheel has spun up, the extra mass is out of the equation and aerodynamics takes over.


yes, they are. P/R, Flanders...Zipp sponsored teams use the 303. those races are flat and fast, they use the 303 for it's strength and width/shape(less chance of pinch flats). the Zipp video about the r&d/making of the 303 is very cool...check it out. 
http://www.youtube.com/watch?v=g37k9ZoWo6Y


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## QQUIKM3 (Apr 20, 2008)

*Oh, yes. .*



cxwrench said:


> yes, they are. P/R, Flanders...


You're right. Any wheel that can do a classic on those roads has got to be tough.


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## looigi (Nov 24, 2010)

Keoki said:


> The guys at Zipp told me the same thing you've just did.


Yep. The only reason to put a shallower rim on the front is to reduce cross wind induced steering issues. The rear wheel influences this much much less so you can get away with a deeper (or even disc) rim. Plus, most people thing deep in front and shallow in back looks funny.


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## Mdrnizd (Oct 21, 2009)

Pharmerbob said:


> One thing to remember is that according to Zipp's website, the 303 will not fit on the rear on an SL-4 Tarmac


I have 303 Firecrest Carbon Clinchers on my S-Work SL-4 Tarmac without any issues.


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## bernithebiker (Sep 26, 2011)

Pharmerbob said:


> One thing to remember is that according to Zipp's website, the 303 will not fit on the rear on an SL-4 Tarmac


Why would a Zipp 303 not fit an SL4 Tarmac? 

(I have one, but I use Mavic Carbon Ultimates, which are great).


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## martinot (Aug 14, 2009)

bernithebiker said:


> Why would a Zipp 303 not fit an SL4 Tarmac?
> 
> (I have one, but I use Mavic Carbon Ultimates, which are great).


ZIPP site indicates potential (I guess clearance) issues but there are some owners of SL4 and 303FCs without problems


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## Pharmerbob (Jun 27, 2011)

*303's*

I copied this from Zipp's Website. 

"The rear 303 Firecrest, however, may present some fitment issues for a small number of road and triathlon frames. The clearance between the chainstay and the rim may not be adequate to avoid contact between each other when ridden under load.

We urge customers who plan on riding the 303 Firecrest to test the wheel within the frame in which they intend to ride it, under normal riding and road conditions, before purchasing. Clearance within individual frames of the same size, from the same manufacturer, may vary. That is why it is imperative that you test the wheel in your frame, or in the frame that you are considering purchasing.

Customers who run into this fitment issue may select any other spoked wheel within the Zipp lineup as an alternative,including the 404 Firecrest with its narrower aero-width profile.

Below is a list of known frames that may present this issue. This list will be updated if this fitment issue is discovered elsewhere.

Specialized Tarmac SL4
Specialized S-Works McLaren Venge


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## Lick Skillet (Aug 21, 2011)

looks can be intimidating - go with the 404's.
Someone mentioned using 25's on the Zipp FC wheels, they are designed to be used with 23's


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## looigi (Nov 24, 2010)

Lick Skillet said:


> ... Zipp FC wheels, they are designed to be used with 23's


Yes, and the the wide FC rims (and others) make 23 tires as wide as 25s on typical 19mm rims.


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## parity (Feb 28, 2006)

I have a pair of Zipp 303 FC tubulars. They are very nice and I can't compare them to the 404. But the 303 are plenty aero without sacrificing weight. I use them for road races which are mostly hilly. I don't know what the compatibility issues are but I can say the rims are much wider then any other wheel I own. And on SRAM Red brakes, you need to completely open the brake. Also the Zipp tangent platinum pro pads are also wider then normal brake pads. So with SRAM red brake calipers, I had to shave down the pads otherwise the wheel would rub the brake pads. I switched to using the Zipp cork brake pads, because the size fits perfectly without the need of shaving down the pad and braking is comparable to the platinum pro pads.


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## dkilburn (Aug 1, 2009)

*303 fc!*

I can't tell you about the 404s.
I did purchase a set of 303 FC this spring. On my 25 mile loop my average picked up about .5 mph vs the Mavic R SYS. Same tires 22 mm Veloflex on the front and a 23 Michelin Pro 3 on rear. I did notice if you can roll over 19 to 20 mph then they just go. Over about 24 to 26 mph they want more. It's like you work to get to 18.5 and a little and then magic starts. I have 2011 Specialized Roubaix with 303 FC on it.

I didn't ride them in the wet so far. 

The braking, you can tell by the sound if you get them warm, but I'm not sure how warm. They do stop good for me, but I'm not hard on them so far. I lay back on hills in the Hudson Valley. The gray pads do have some wear.

On of the group riders have a set of 404 - 808, he said they have a sweet spot for the speed which he told me was in the mid to upper 20's.

===========
Specialied
2011 S Works Roubaix
2010 S Works Roubaix
2008 CrossTrail


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## martinot (Aug 14, 2009)

Great comments. Thx guys. I am sure I'll demo both sets and possibly MadFiber tubies too - local guys love them.


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## gordy748 (Feb 11, 2007)

They're both great wheels. The 303s will be slightly more comfortable and a little lighter, the 404s will be a little more aero.

Overall, unless you spend a lot of time on steep climbs, the aero benefits will outweigh the lightness benefits. Given you like to escape and work with fewer riders, aero is more important. And given you race on rolling hills, I'd point you towards the 404s.

As well as some nice FMB tubulars.


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## dkilburn (Aug 1, 2009)

*Do a Test Ride*

Good morning

You should do a test ride on your choices. After the week of testing for me. I didn't want to give them back.

Also, You may try Reynolds, they have a test program.

Good Luck on the choice and enjoy the ride.

=============
Specialized
2011 S Works Roubaix
2010 S Works Roubaix
2008 CrossTrail 
.


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## mgringle (May 20, 2011)

*Insanely strong?*

It was mentioned that the 303FC is very strong. Would 303FC clinchers be sufficient as a good all-around wheel for a 225 lb rider? Seems like they would be great for all different types of terrain, but I am wondering if the weight limit might be an issue if I'm putting a couple hundred miles a week on them around town in a fairly hilly area.


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