# Disc Front Brake / Rim Caliper Rear Brake Experiment



## mrwirey (May 30, 2008)

So here goes nothing:

My Hypothesis: Since most of a bike’s stopping power is found in the front wheel and discs provide superior stopping power/modulation under most conditions; running a disc brake front/rim caliper rear brake set up should provide a better balance of stopping power and modulation when compared to the same bike with rim brakes front and rear while avoiding the weight penalty (arguably slight) and complexity associated with a full disc setup. (… okay … so I’m bored…)

My Control Bike: 2012 Cannondale CAAD10-1 with full Shimano Dura Ace 7800 10 Speed Group and H-Plus Son Archetype Rims laced to Ultegra 6800 Hubs

My Test Mule: 2012 Cannondale CAAD10-1 with Shimano full Dura Ace 7900 10 Speed Group.

The Relevant Test Components: 
- The Test Mule
- 2015 Cannondale Synapse Disc Carbon Fork
- 2015 TRP HY/RD Hydraulic Front Disc Brake Caliper with 140mm TRP Disc
- 2012 Shimano Ultegra 6700 Rear Brake caliper with Corima Red Brake Pads
- 2015 25mm Carbon Clincher Wheelset (new off eBay); Front is Disc Compatible; Rear is Standard Rim Brake Compatible (I’m still waiting on the wheels, but I should have this thing together by X-mas)

Wish me luck!

Very respectfully, Tim


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## SwiftSolo (Jun 7, 2008)

Tim,
I think it is a great experiment. We can only guess what the outcome will be.

My gut feeling is that initially. the rear will contribute very little and as the rim gets scrubbed dry, you may find the rear wheel locking up untill you reduce lever pressure. Even if that happens, you may be able to adapt.

Let us know and don't give up on it until you've tried it enough to have a shot at adapting.

Do you ride on downhills with hairpins?


mrwirey said:


> So here goes nothing:
> 
> My Hypothesis: Since most of a bike’s stopping power is found in the front wheel and discs provide superior stopping power/modulation under most conditions; running a disc brake front/rim caliper rear brake set up should provide a better balance of stopping power and modulation when compared to the same bike with rim brakes front and rear while avoiding the weight penalty (arguably slight) and complexity associated with a full disc setup. (… okay … so I’m bored…)
> 
> ...


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## ogre (Dec 16, 2005)

What are you trying to do? Piss off the disc brake fanatics AND the rim brake diehards all at the same time?


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## Fredrico (Jun 15, 2002)

mrwirey said:


> So here goes nothing:
> 
> My Hypothesis: Since most of a bike’s stopping power is found in the front wheel and discs provide superior stopping power/modulation under most conditions; running a disc brake front/rim caliper rear brake set up should provide a better balance of stopping power and modulation when compared to the same bike with rim brakes front and rear while avoiding the weight penalty (arguably slight) and complexity associated with a full disc setup. (… okay … so I’m bored…)
> 
> ...


Just be careful not to go over the handlebars!


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## SwiftSolo (Jun 7, 2008)

That's good advice but I doubt that would be an issue with TRP's--depending on the lever. Even with shimano hydros, it only takes a few stops to generally adapt. Takes much longer to learn how to take full advantage on twisting mountain descents. I'm guessing I have maybe 4000 hairpins under my belt on road hydro discs and I still feel I'm on the steep part of the learning curve.


Fredrico said:


> Just be careful not to go over the handlebars!


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## upstateSC-rider (Aug 21, 2004)

I have an old school mt bike set up like that, Avid BB-7 in the front and V-brake in the back, the only reason it's not full disc is because it doesn't have disc mounts in the rear.
Works better than full V-brake but still way less power than even low-end hydro discs.


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## mrwirey (May 30, 2008)

SwiftSolo said:


> Tim,
> Let us know and don't give up on it until you've tried it enough to have a shot at adapting.
> 
> Do you ride on downhills with hairpins?


Swiftsolo,
Thank You for the encouraging words and don't worry ... I won't give up easily. This will be a dedicated project bike so no need to revert back to original. 

I don't have many steep hairpins, but I do have steep, somewhat sketchy - due to gravel - roads. I may take a trip to Mt. Graham as it is very steep with lots-o-hairpins on the descent. That would be a very good test of the set up.

I'll report my findings once I have some.

Very respectfully, Tim


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## mrwirey (May 30, 2008)

ogre said:


> What are you trying to do? Piss off the disc brake fanatics AND the rim brake diehards all at the same time?


ogre,
I know, right? :thumbsup:

Very respectfully, Tim


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## mrwirey (May 30, 2008)

upstateSC-rider said:


> I have an old school mt bike set up like that, Avid BB-7 in the front and V-brake in the back, the only reason it's not full disc is because it doesn't have disc mounts in the rear.
> Works better than full V-brake but still way less power than even low-end hydro discs.


upstateSC-rider,
Good to hear you've done it. I did a lot of googling, but couldn't find anyone who'd really tried this on a road bike so it got me curious. I'm trying not to presuppose the outcome. I'm sure it will look a bit odd, but I'm hoping for the best.

Very respectfully, Tim


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## BCSaltchucker (Jul 20, 2011)

ogre said:


> What are you trying to do? Piss off the disc brake fanatics AND the rim brake diehards all at the same time?


Zing!

I love it.

actually he only pisses off me. I am that guy who would run disk hydro ont he back, and cable brake on the front. I did just that 20 years ago on a DHfreeride bike (RockyMtn DHRace, with Hayes hydro rear disk,and Avid front cable brake). Did not want so much power in the front to prevent endo-ing, but I did want very good power and modulation for the rear. Extremely steep crude trails.

The thing is, front brakes always felt to have more power and modulation not just because of the leverage advantage of front brakes, but also because the cable and housing is so short you get a lot less sponginess, compared to back cable brakes. So it is nicer having the hydro feel in the rear, imho, if you can only have one brake. (at the time disk brakes hard to come by and frames and forks were not equipped with mounting tabs - I made my own mount)


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## yancy0303 (Feb 13, 2008)

I also rode this setup on an old mt bike. I believe it was referred to as a "mullet setup", all business up front and a party out back.


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## Jay Strongbow (May 8, 2010)

mrwirey said:


> So here goes nothing:
> 
> My Hypothesis: Since most of a bike’s *stopping power is found in the front wheel* and discs provide superior stopping power/modulation under most conditions; running a disc brake front/rim caliper rear brake set up should provide a better *balance* of stopping power and modulation when compared to the same bike with rim brakes front and rear while avoiding the weight penalty (arguably slight) and complexity associated with a full disc setup. (… okay … so I’m bored…)


From what I can understand you have it backwards. If the front is stronger than the rear (aka not balanced stopping power when using the same brakes) using a stronger brake on the front will only throw that balance off further not bring the power more into balance.


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## SwiftSolo (Jun 7, 2008)

I think the difference is that traction is very limited on steep dirt descents. Because the gradient is often twice as steep as anything we see on road bikes, a disproportionate amount of the weight/traction is on the front, even when behind the seat. 

On the pavement, steep, sharp turns put even more or the resistance on the front wheel. Braking hard with your ass behind the seat will still make it hard to keep much weight on the rear tire. 

With hydro disc, precision makes trying to find the balance interesting. On dry pavement, you can hear your rear tire squawking a bit just before breaking loose and you can maintain that level of braking. Beyond that point, more pressure on the front brake will cause the rear tire to break loose as will more pressure on the rear brake. Your only option is to get further behind the seat if you need to increase deceleration.

Look for ex mountain bikers to gain an even bigger advantage on technical road descents in the Giro and Tour this year.


BCSaltchucker said:


> Zing!
> 
> I love it.
> 
> ...


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## AJ88V (Nov 14, 2012)

Disc front, cantilever rear was a very common setup on mountain bikes for awhile, especially for lower end bikes trying to keep the price down when disc brakes were becoming the standard and not the exception.

I'm not sure you'll see that big a difference in feel with the TRP hy/rd vs your excellent Ultegra rear setup, but since I've never straight-up compared a road caliper to a road disc, it will be very interesting to see what your impressions are. :thumbsup:

FWIW, I'm about to install a pair of Hy/Rds on my CX bike (parts came in last night). The mechanical discs absolutely suck (too used to hydros on my MTB). My son has the SRAM hydros on his CX and they feel very much like good MTB brakes (meaning wunderbar!).



mrwirey said:


> upstateSC-rider,
> Good to hear you've done it. I did a lot of googling, but couldn't find anyone who'd really tried this on a road bike so it got me curious. I'm trying not to presuppose the outcome. I'm sure it will look a bit odd, but I'm hoping for the best.
> 
> Very respectfully, Tim


You're using your CAAD10 on gravel? Pretty skinny wheels/tires for that. I've had more than enough pinch flats on my CX in the past year running 35mm tires. LOL!

Good luck with your experiment. - v/r, AJ


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## deviousalex (Aug 18, 2010)

I was considering this for my CX bike. It has both canti and disc mounts but the rear is 130mm spaced (not 135mm) so it's hard to find disc brakes that work for it. Problem is then I'd have so many front wheels I don't need!


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## mrwirey (May 30, 2008)

*Frankendale is alive!!!!*

Bike is all together. I rode it for the first time today. Bottom Line: My initial impression is their is negligible difference between the Shimano Ultegra caliper front brake and the TRP HY/RD I replaced it with. Both work equally well. Granted, I have yet to really stress the bike in nail biting braking situations, but I don't think I will really appreciate the front disc until I get caught in a downpoor. Operative word being 'caught' as I don't ride in the rain by choice. I will provide more insights as I put more miles on the setup.
Very respectfully, Tim


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## bvber (Apr 23, 2011)

mrwirey said:


> My initial impression is their is negligible difference between the Shimano Ultegra caliper front brake and the TRP HY/RD I replaced it with.


If the disc brake pads are new, it will take a bit of time to develop its stopping efficiency to full potential. It did with mine.


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## mrwirey (May 30, 2008)

bvber said:


> If the disc brake pads are new, it will take a bit of time to develop its stopping efficiency to full potential. It did with mine.


bvber,
I guess I should've held off judgement until the disc pads were fully broken in. I'll continue to bed them in and evaluate. Thank You.

Very respectfully, Tim


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## jeffpoulin (Sep 13, 2008)

mrwirey said:


> ... but I don't think I will really appreciate the front disc until I get caught in a downpoor. Operative word being 'caught' as I don't ride in the rain by choice.


I applaud your experiment, but I must admit that I'm missing the point of having a front disc for fair weather riding. In dry conditions, my calipers work as well as my discs. I only notice a difference when riding in the rain (which I do regularly as a bike commuter). Maybe for those few times when you're caught, as you said.


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## mrwirey (May 30, 2008)

jeffpoulin said:


> I applaud your experiment, but I must admit that I'm missing the point of having a front disc for fair weather riding. In dry conditions, my calipers work as well as my discs. I only notice a difference when riding in the rain (which I do regularly as a bike commuter). Maybe for those few times when you're caught, as you said.


jeffpoulin,
I was in a bike race last year, which had patches of intermittent rain. I was riding my Madone with Boyd full carbon clinchers and I kept forgetting my brakes didn't work as well in the wet as they do in the dry. :blush2: The worse that happened was I unintentionally went to the front of the paceline when the guy in front of me suddenly slowed, but it got me thinking about having a disc equipped race bike for just such occasions. 

Although this bike will probably be very niche in the larger scheme of things, I'm sure it will be worthwhile at some point. It's all about N+1 anyway, right? :thumbsup:

Very respectfully, Tim


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## robt57 (Jul 23, 2011)

I have 3 bikes I intentionally allowed for weaker rear braking. One has a cable pull adapter on the front and not the back [V brakes]. Another has a hy/rd 180mm front rotor with a 160 rotor with a $16.00 jamooky brand rear caliper. Another a V rear with a BB7 front, that had previously been a mini V front with a normal V rear. I tend to be fussy about brakes too. All the V brake using salmon pads and always nice clean and dressed rim braking surfaces. My road caliper bike cleaning [all salmon pads too] includes brake surface rim cleaning with little scouring pad sections. I spend more time on the rims than the bike. I also really have at the rims when changing tires out. I do what I call 'dressing rims' often as needed or sooner as a preventive.

Seems having them all at the most efficient state of operation is better that coin thrown at the 'perfect setups' that are not maintained IMO.


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## mrwirey (May 30, 2008)

robt57 said:


> Seems having them all at the most efficient state of operation is better tha[n] coin thrown at the 'perfect setups' that are not maintained IMO.


robt57,
I couldn't agree more. I tend to 'maintain' (and tinker) as much as I 'ride' to ensure everything is operating the best it can and the way I intend it to. Luckily for me I live in a dry-er area (Arizona) so things don't get mucked up very often and I don't get a lot of rim/brake damage ... on the asphalt anyway. 

Very respectfully, Tim


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## velodog (Sep 26, 2007)

mrwirey said:


> ogre,
> I know, right? :thumbsup:
> 
> Very respectfully, Tim


Good plan.


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## wgscott (Jul 14, 2013)

I thought this would be a good cheap way to upgrade my kid's mountain bike, since all you have to get is a fork with the brake mount and a wheel with a disc hub (in addition to the brake). I never got around to trying it out, so I am glad someone did.

There is a lot of elaborate advice for bedding in the pads. I find pedaling hard with the brake squeezed down does it pretty quickly.


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## mrwirey (May 30, 2008)

wgscott said:


> I thought this would be a good cheap way to upgrade my kid's mountain bike, since all you have to get is a fork with the brake mount and a wheel with a disc hub (in addition to the brake). I never got around to trying it out, so I am glad someone did.
> 
> There is a lot of elaborate advice for bedding in the pads. I find pedaling hard with the brake squeezed down does it pretty quickly.


wgscott,
I got the fork off eBay for $100 (new take off), the TRP HY/RD for $110, and I paid $450 for the carbon clinchers. I could have spent less on the wheels, but I wanted it to look matchy-matchy. 

Aesthetically, the project turned out much better than I thought it would. It looks very 'factory' vice 'garage built'. I'm sure using a Cannondale fork on a Cannondale helped out immensely. One side benefit I didn't expect was the Synapse fork seems to damp the 'road buzz' a bit better than my other CAAD10 running a similar cockpit/wheel/tire/pressure setup ... an unintended yet pleasant surprise.

I will give your bed in method a go. It's raining today so it'll have to wait till tomorrow. 

Very respectfully, Tim


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## AJ88V (Nov 14, 2012)

mrwirey said:


> Bike is all together. I rode it for the first time today. Bottom Line: My initial impression is their is negligible difference between the Shimano Ultegra caliper front brake and the TRP HY/RD I replaced it with. Both work equally well. Granted, I have yet to really stress the bike in nail biting braking situations, but I don't think I will really appreciate the front disc until I get caught in a downpoor. Operative word being 'caught' as I don't ride in the rain by choice. I will provide more insights as I put more miles on the setup.
> Very respectfully, Tim


I hadn't caught that you were using carbon rims in your original post. I'll bet the disc front will provide much better braking over that - and let you save your carbon rims while you're at it.

Update us on your TRP Hy/Rd too. I just installed a pair on my CX bike and am surprised about the amount of travel compared to the SRAM hydros on my son's CX. Wondering if this will improve as the pistons self-adjust move the pads out nearer the disc as the brakes get used (barely ridden the bike with the crappy weather here). I've seen online that you sometimes have to add additional fluid to the brake reservoir to make up for the extended pistons.


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## mrwirey (May 30, 2008)

AJ88V said:


> Update us on your TRP Hy/Rd too. I just installed a pair on my CX bike and am surprised about the amount of travel compared to the SRAM hydros on my son's CX. Wondering if this will improve as the pistons self-adjust move the pads out nearer the disc as the brakes get used (barely ridden the bike with the crappy weather here). I've seen online that you sometimes have to add additional fluid to the brake reservoir to make up for the extended pistons.


AJ,
The HY/RD caliper has about perfect lever actuation with the newer Shimano shift/brake levers as Shimano changed the amount of cable pull over their older design. 

You may want to check out this video as a solution to your problem. 

http://youtu.be/8aBa3sGUUhs

Very respectfully, Tim


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## Migen21 (Oct 28, 2014)

That mod seems a bit risky to me. You are (potentially?) compromising the integrity of lever arm. If that thing breaks under duress... yikes...


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## mrwirey (May 30, 2008)

Migen21 said:


> That mod seems a bit risky to me. You are (potentially?) compromising the integrity of lever arm. If that thing breaks under duress... yikes...


Migen21,
That's an official TRP video. I don't see any structural issues with that fix if done correctly. If unsure, you can always take it to your trusty LBS.
Very respectfully, Tim


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## Migen21 (Oct 28, 2014)

mrwirey said:


> Migen21,
> That's an official TRP video. I don't see any structural issues with that fix if done correctly. If unsure, you can always take it to your trusty LBS.
> Very respectfully, Tim


Hey, I love my bike (and life) hacks as much as anyone else. As much as I'd love for this to be the simple solution to this problem, I'd be careful dragging a hacksaw across that lever arm. 

Also, I'm fairly certain that is not a TRP produced video. This is their official channel, and I don't see any sign of that video here.

https://www.youtube.com/user/TRPBrakes/videos


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## mrwirey (May 30, 2008)

Migen21 said:


> Also, I'm fairly certain that is not a TRP produced video. This is their official channel, and I don't see any sign of that video here.
> 
> https://www.youtube.com/user/TRPBrakes/videos


Migen21,

Not up for a back and forth, but It's a TRP video. Take a look at the Redline CX bike with Campy in the background on this video https://www.youtube.com/watch?v=1T2RLgQoyvs ; it is the same bike used in the video I posted earlier at http://youtu.be/8aBa3sGUUhs . 

If you are concerned about the origin of, or your perceived safety issue due to the content of the video; drop the good folks at TRP a line to let them know your concerns and report back your findings. I'm sure the TRPsters could have the video removed if it was espousing something erroneous or dangerous. They've been very responsive to me in the past. Contact URL: TRP

Very respectfully, Tim


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## trumpetbiker (Oct 9, 2013)

mrwirey said:


> upstateSC-rider,
> Good to hear you've done it. I did a lot of googling, but couldn't find anyone who'd really tried this on a road bike so it got me curious. I'm trying not to presuppose the outcome. I'm sure it will look a bit odd, but I'm hoping for the best.
> 
> Very respectfully, Tim



not the first time the front disc conversion has been done, and you will see more in the coming years. all dependent on how much you like your frame, and whether or not you are willing to put the money into it to make it a front disc bike, and why you want to make it as such.

this latest project is with a Quiring from the early 2000's. whiskey disk fork, trp caliper. should be good. my last one was a Lemond Victorie Ti. I'll post when finished.

for those concerned about the safety and issues of front to back, throw that out the window. in wet weather or muddier conditions, its much safer and the braking is all common sense so you go for the best braking possible.

I think they look cool, on top of that, so thats an added bonus.


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## mrwirey (May 30, 2008)

trumpetbiker,
Well I guess I'm not the only 'roadie' making the front disc conversion after all. 

I agree the cost has to be considered when taking on this project. I probably could've sold my CAAD10 and used the money from the sale along with the money I put into the conversion to buy a new CAAD12 Disc and pretty much broke even. Somehow though, I like my CAAD10 Frankenbike more than a CAAD12 Disc. I really don't need a disc in the rear and I like the simplicity of the caliper brake back there. 

I really like your Quiring. I'm looking forward to seeing your other project as well.

Very respectfully, Tim


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## trumpetbiker (Oct 9, 2013)

mrwirey said:


> trumpetbiker,
> Well I guess I'm not the only 'roadie' making the front disc conversion after all.
> 
> I agree the cost has to be considered when taking on this project. I probably could've sold my CAAD10 and used the money from the sale along with the money I put into the conversion to buy a new CAAD12 Disc and pretty much broke even. Somehow though, I like my CAAD10 Frankenbike more than a CAAD12 Disc. I really don't need a disc in the rear and I like the simplicity of the caliper brake back there.
> ...



my last conversion I turned it back the way to original shape. it was a nice Lemond Ti frame, but the subtle riding characteristics of the bike changed --------- most likely because the geometry was turn of the last century's racing geometry(a team bike) and I shouldn't have messed with it. 

this Quiring is a 2003 or so, more modern upright geometry with a taller headtube, and it fit me well with the ritchey pro carbon fork so it was a good candidate. I didn't want the full front/rear disc either, like you tim, I already have a nice steel volagi viaji that I can take anywhere, this one has similar geometry to the volagi as well which fits like a glove. but its lighter, and more road geometry. overall, it should come in around 18lbs with the front only disc brake and front disc rear non disc wheelset(stan's notubes alpha 400) which I already run non disc on another bike. carbon would be great, but I'm better concerning myself with my own conditioning, and I keep up already.

the bottom line on the front disc only: know your bike. not all frames work well converted over with another fork. 

and with the changed out wheel(don't go cheap), brake and rotor(easiest and still works very well with spyre or HyRd), cable/housing and time involved, it gets expensive. 

tim and a couple of others know this already, but we aren't on a team with these bikes, they are a high performing ride for adverse conditions and better overall braking than rim brakes -------- the goal is smooth consistent fast stop in wet/dirty roads. 

but I love my upgraded steel ultegra 6700 2001 Lemond Zurich, a classic 853 I won't be converting over because I love the ride ----------- and rim calipers work great in the summer. beautiful bike that already works great.

I've rebuilt 3 Lemond Poprad discs to Ultegra/trp and volagi wheelsets, all sold right away ---------- discs are now AND the future ------------- but if you don't have one and like your existing ride, there are a host of new carbon road disc forks that are light and strong, and the strong non slipping front brake is worth it during a steady rain downhill. the availability of nice matching front wheels being manufactured are numerous as well, and not real expensive if you buy right.

if it saves your life, who's going to talk about the perfect braking front to back ratios, theories and two vs one disc?

that video was trick too, btw. the calipers are designed to easily withstand that slot modification.


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## trumpetbiker (Oct 9, 2013)

mrwirey said:


> trumpetbiker,
> Well I guess I'm not the only 'roadie' making the front disc conversion after all.
> 
> I agree the cost has to be considered when taking on this project. I probably could've sold my CAAD10 and used the money from the sale along with the money I put into the conversion to buy a new CAAD12 Disc and pretty much broke even. Somehow though, I like my CAAD10 Frankenbike more than a CAAD12 Disc. I really don't need a disc in the rear and I like the simplicity of the caliper brake back there.
> ...



done deal. rides great.

cost of the fork, wheel and trp caliper, cable and housing, no labor, 600.00 with new parts. figure a new full frame alone in titanium would be 1600-2800.00 alone with no headset or fork, and compare that with a high end titanium used if you liked it and fit well at 600-1000.00. My frame used was 400 and included a nice ritchey pro fork, to be used on another bike (350.00 value, and its like new) so really, the frame with an existing chris king headset cost me near nothing. not a bad experiment.

and here's the bottom line in these conversions----------the front brake takes the brunt of the force, if you have a decent rear brake with red pads and don't do trail riding, you need nothing more. it stops great here in the rainy NW and stops exceptionally well in the dry, without adding appreciable weight (for those weight weenies out there). I'm not racing. and I keep up fine with my cohorts, thank you. at 18lbs, what more do you need?


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## mrwirey (May 30, 2008)

trumpetbiker said:


> done deal. rides great. what more do you need?


Trumpetbiker,
You are a mad scientist after my own heart! In answer to your question, "what more do you need?" Nothing. Enjoy the ride!
Very respectfully, Tim


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