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daft UCI attitude to disk brakes on road bikes?

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Mar 10, 2009
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I think that there is mileage in this discussion. I'm all for more control through increased braking power and am open to disk brakes. I'm not even sure that there is neccessarily a weight penalty. After all Cannondale have proven that it is possible to do away with an entire fork leg and still produce a stiff and light disk-equipped front end.
 
May 12, 2009
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I wouldn't use a $22000 ultra-custom bike as an example for anything. A test bed maybe, but not an example.
Maybe it is actually stiffer. But in a road test, I'd bet the default is to imagine that kind of thing to justify the fact that it costs 4 times as much as a Colnago Extreme Power.
 
Mar 10, 2009
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slcbiker said:
I wouldn't use a $22000 ultra-custom bike as an example for anything.

Hey the Beru F1 Systems Company made it so that alone adds £23,999 to the price of the bike :D, we all know who they are and their solid cycling background after making one prototype bike :rolleyes:
 
Apr 10, 2009
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The weight argument doesn't hold much water really, it is easy to build a bike under the UCI weight limit. I'm sure you could still build one to the weight limit with a disk front and possibly rear without resorting to an F1 companies 'blue sky' project...
 
It's performance not weight

Yes NapoleanD is right, it should be perfectly possible to build a bike at the UCI weight limit with disks front & back & a power-meter (given a couple of years of evolution on the Cyclocross scene). But all the Luddites who've contributed to this discussion need to understand that current road bike brakes are pretty hopeless compared with Discs or maybe they just haven't ridden a mountain bike fitted with hydraulic disk brakes! I was out in the Chiltern hills last week on a drizzly day and the friend I was riding with was having real trouble stopping with his £600 carbon calipers & carbon rims. The technology just wasn't working. I'm just glad we weren't going down an Alpine pass or he could have ended up like Pedro Horillo
 
Mar 18, 2009
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ukpaul said:
James

Sorry I dont agree with you there.Road bikes are all about the weight adding discs will not help road bikes at all.


- far improved modulation for more *controllable* power. Yes maybe.


- lighter rim weights as rims would no longer have to be built to cope with brake clamp forces. Lighter rims at the expense of heavier disc rotors,brakes,hoses.


- fewer tire blowouts due to heat build-up. ??? Really Ive been riding for more than 20 years and have never heard of anyone having a tire blow out due to heat build up.


- more aerodynamic rim shapes . very minimal.

I don't understand this. You state that discs won't help road bikes at all. But then you go on to say they modulate power better. They allow for lighter rims. They allow for more aero rims. They alleviate heat build up in rims. You also missed the biggest benefit of them, they work incredibly well in the wet, even on alpine descents. In fact the only thing you can say that isn't in favor of discs is that they are heavier.

The weight may surprise you a bit. 7900 Dura ace calipers with brake pads weigh 294grams for a pair. Record Skeleton 282grams, Sram Red 270grams.

R1 hydraulic disc calipers weigh 112grams per pair. 140mm scrub rotors weigh 84 grams per pair. So a set of calipers and rotors is 196grams. Almost 100 grams lighter than 7900 rim brakes. Hydraulic housing and fluid is lighter than wired cables and housing and the lever weights are close. So you've got a total weight savings of 80-100 grams but at the same time you have the ability to make a much lighter clincher rim moving the important outer rotating mass inward.

So basically you get a ton of performance improvement over Dura Ace, but with the weight of Zero Gravity.

So now perhaps you can tell me again why discs would be so terrible on road bike.
 
Jun 15, 2009
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Disk brakes have just not been sufficiently refined for road use. They have been tried on road tandem bikes for years but with limited success. Front disks suffer from two problems. Overheating on long descents & vibration transmitted through a lightweight fork. Rear disks live a happier life on a tandem & do an OK job if used in moderation. For a single road bike a rear disk would be overkill. Even in the mountain/ cross world disk brakes are only an advantage in muddy conditions.
 
Why discs are not refined for road use.

embankmentlb said:
Disk brakes have just not been sufficiently refined for road use. They have been tried on road tandem bikes for years but with limited success. Front disks suffer from two problems. Overheating on long descents & vibration transmitted through a lightweight fork. Rear disks live a happier life on a tandem & do an OK job if used in moderation. For a single road bike a rear disk would be overkill. Even in the mountain/ cross world disk brakes are only an advantage in muddy conditions.

Yes, and the only reason they haven't been refined for road bikes is that they're not approved by the UCI! And you're wrong that disk brakes are only an advantage in muddy conditions. They're better in all conditions but the difference becomes a gulf in the mud and the wet.
 
May 12, 2009
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Wheel changes for sure would be slower, unless someone builds some sort of disk caliper release.

Not sure what tandems have to do with installation on regular bikes. Tandems are carrying twice the weight, so it's not suprising if there were overheating issues on discs designed fo a single. However, discs are certainly used on downhill mtbs and more obviously on motorcycles, in each case dealing with being able to brake heavier weights on long descents.
 
Jul 6, 2009
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just like to say having built a disc brake road bike 2 years ago and done 4000 miles on it mainly in derbyshire england i would not use rim brakes again if you payed me. my brakes are avid bb5 mountain bike ones and have only had one pair of new pads in that time. i am building a new bike now that will have bb7 road brakes, the rear caliper is to be mounted between the seat stay and chain stay and i am making the frame from reynolds 853 tube.
 
Mar 10, 2009
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Time warp

I have heard this entire discussion about 15 to 18 years ago. V brakes vs. disk on MTB. There are different answers, but here disks rule.
I don't think we will see them anytime soon on road race bikes.
From the Santana web site I will reflect their opinion as I recall it. Front disks cannot be added to tandem carbon forks for fear they will damage them from heat. That is for a tandem and i doubt a single has such high brake loads, but if so, I am sure they could solve that engineering problem.
Disks for CX first. Soon I hope too.
 
May 26, 2009
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RDV4ROUBAIX said:
Forget all this talk of disk this disk that. The future of stopping your bike lays in electromagnetics. Frictionless baby!

Sounds good, who knows^^

On topic, the biggest advantage I can think off is carbon rim stopping power. Also, it would put to an end the issues of having to swap pads between alu and carbon wheelsets.

I don't see a real disadvantage (weight isn't an issue), so why not?
 

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