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meanwhile on the road disc brake front
Last Post 06/04/2014 09:45 PM by Mike Shea. 58 Replies.
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79pmooney

Posts:1175

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06/03/2014 12:56 PM
I just had this "Duh!" Of course we will go all disc for road racing. Only a matter of time. This is a capitalistic world we live in. By going disc, every bike out there owned by the teams at the high levels and individual racers at the lower amateur ranks will have to be replaced. Every one. That means how many new bike sales? And new brake set sales? Thousands? Times what, 3, 10, 100 for ther wannabees that have to have the same bike? And $$ to manufacturers, distributors and shops. Millions? It's going to happen. Money talks.

Driving forces in this huge change? How about Giant, Specialized, Trek, Shimano and SRAM.

Not saying I like it. In fact I wish this thought never happened.

Ben
Cosmic Kid

Posts:1150

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06/03/2014 01:12 PM
ben, this gets brought up every time there is a new "innovation." STI, dual pivot brakes, 9 speed, 10 speed, suspension, disc brakes.....you name it. "IT's ALL MARKETING!! It is just being driven by the manufacturers so they can force us to buy new stuff."

What I can tell you is that never once, in over 10 years of working in the bike biz, did I ever participate in a meeting where such strategies were theorized, strategized or even suggested. The only thing the product guys are doing is trying to find new ways to make cool stuff that people will want to buy. That's about it. Hell, I can pretty much guarantee that more time is spent on choosing colors than worrying about disc brakes for the road, or any other product specification.
Just say "NO!" to WCP!!!!
Keith Richards

Posts:743

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06/03/2014 01:33 PM
Posted By Evan Solida on 06/03/2014 10:51 AM
You know, I didn't think about continental and domestic racing. I was just thinking about how the UCI would need to demand ALL teams use discs rather than having a mix throughout the peloton. That would cause a lot of problems if some riders are able to dive-bomb hairpin descents while others have to scrape away speed leading into turns. The pro peloton is a very small group and is comparatively simple to manage. But if amateurs start showing up with discs while most still have rim brakes, that's really going to be bad.


I don't think it will make the huge difference you think. The limiting factor at the end of the day is the tiny contact patch that is a road bike tire. We have this discussion in car land all the time. If you upgrade your brakes and don't upgrade to a stickier tire, the differences are not going to be that huge in terms of raw braking. In fact in car racing circles, the big reason for brake upgrades is heat dissipation and the loss of braking power that comes from overheated brake components, not a drastic increase in braking power or shorter stopping distances.

The car racing motto is, "if you can lock up your brakes with the setup you have, adding stopping power will not make any difference."
----- It is his word versus ours. We like our word. We like where we stand and we like our credibility."--Lance Armstrong.
ChinookPass

Posts:467

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06/03/2014 03:01 PM
that you KR? How's the ride?

Keith Richards

Posts:743

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06/03/2014 03:04 PM
Aww....no man. Y'all know what kind of techno grouch I am. I could never own/ride such a thing. Too industrial for me.
----- It is his word versus ours. We like our word. We like where we stand and we like our credibility."--Lance Armstrong.
ChinookPass

Posts:467

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06/03/2014 04:26 PM
I didn't think so but thought I'd ask. That's the great thing about bikes, everyone's got their taste and flavor that suits them.
Cosmic Kid

Posts:1150

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06/03/2014 05:27 PM
Posted By Keith Jackson on 06/03/2014 01:33 PM
Posted By Evan Solida on 06/03/2014 10:51 AM
You know, I didn't think about continental and domestic racing. I was just thinking about how the UCI would need to demand ALL teams use discs rather than having a mix throughout the peloton. That would cause a lot of problems if some riders are able to dive-bomb hairpin descents while others have to scrape away speed leading into turns. The pro peloton is a very small group and is comparatively simple to manage. But if amateurs start showing up with discs while most still have rim brakes, that's really going to be bad.


I don't think it will make the huge difference you think. The limiting factor at the end of the day is the tiny contact patch that is a road bike tire. We have this discussion in car land all the time. If you upgrade your brakes and don't upgrade to a stickier tire, the differences are not going to be that huge in terms of raw braking. In fact in car racing circles, the big reason for brake upgrades is heat dissipation and the loss of braking power that comes from overheated brake components, not a drastic increase in braking power or shorter stopping distances.

The car racing motto is, "if you can lock up your brakes with the setup you have, adding stopping power will not make any difference."


Agreed, but the advantage of disc brakes is not the power (people could lock up v-brakes easily before discs), it is 1) modulation and 2) improved performance on wheels with poor braking characteristics (i.e. carbon).

Personally, I see a place for them in CX and gravel road / touring bikes. I have yet to be convinced of the applicability on the road. My hesitation is due to 1) safety (hot discs in a pile-up) and 2) aerodynamics. You are losing WAY more in aerodynamics than you are gaining in performance.
Just say "NO!" to WCP!!!!
longslowdistance

Posts:701

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06/03/2014 07:46 PM
Right on CK!
We forumites of good will but varied experience go round and round on this topic. Discs are way, way, way better for almost every mtb application, But what does that have to do with road riding? What we know for certain ( sorting with facts from the opinions):
Discs are better in the rain, HAVE BETTER MODULATION, and are more powerful.
Discs are way better for gravel road grinders in the mountains (I know from personal experience this is true and so do many others).
Discs weigh more and can be more complicated in terms of maintenance and rapid wheel changes.
Heat dissipation may be an issue for major alpine-like descents (think Stelvio, but without the snow to cool things off). The jury is still out out on this and it may be months or years before hydraulic discs are vetted for long high speed descents that require lots of braking.
Hydraulics are better in almost every way but mechanicals have some advantages because of simplicity, less fear of fade, wider pad clearance, and idiot-proofness.

The rest has been a lot of posing and opinions borne of ignorance, prejudice or wishful thinking.
Lets see what Shimano, SRAM, et. al. actually put on the market and see how it works.
Cars, motorcycles, scooters all use discs brakes. Sure, they weigh more and (mostly) generally go faster than bikes, but that performance may or may not ultimately extend to bicycles that has nothing to do with marketing, profits or similar. "I don't need no stinking brakes that work better than what I got" is fine for some, but retrogrouches be open minded as this unfolds. . . .
Orange Crush

Posts:1217

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06/03/2014 09:05 PM
Funny discussion on advantages; this is the least relevant part as to if and when we will see discs in peleton.

If you scroll back to page 1, the pertinent talking points are uniformity of standards and ability of all pro team frame suppliers to offer discs. Discs will be introduced across the board, not peacemeal and to a single standard (ISO maybe). That is what discussion between UCI and stakeholders is about.
Orange Crush

Posts:1217

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06/03/2014 11:53 PM
2016 or 2017 is the estimate for their introduction in peleton. I guess I will hold off purchasing a new steed until then.
Cosmic Kid

Posts:1150

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06/04/2014 04:16 PM
I'd still like to see more investment / development of hydraulic calipers for road bikes ala the new SRAM Red hydraulics. For road bikes, I think these make WAY more sense than discs.

Just say "NO!" to WCP!!!!
CERV

Posts:151

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06/04/2014 06:33 PM
I know some engineers designing this stuff, and heat dissipation is still the major issue. This is where you can't make any real comparison to your experience using MTB discs.
On one hand, there will always be a push for road discs to be smaller and lighter than mtb disc, but on the other hand they need to dissipate a LOT more energy.

Amount of heat dissipated = change in kinetic energy = 1/2mv^2.
82kg (bike+rider) on a road bike slowing from 50km/h to 40km/h = 2837J
85kg (bike+rider) on a mountain bike slowing from 30km/h to 20km/h = 1639J

This sort of difference in magnitude of energy to dissipate is also what you would see drag braking a road bike down a typical road descent vs drag braking a mountain bike down a typical mtb descent.

Road bikes travelling faster would have better cooling available from more wind, but in the interest of making it aero, you'd also want to design the frame/fork around the disc to move air smoothly around the disc assembly instead of over the rotor which would cause turbulence. All this must be accomplished on a smaller, lighter rotor than on your mtb.
Ride On

Posts:442

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06/04/2014 09:30 PM
Disc brakes for road bikes is a solution to bad design in the first place, carbon clincher wheels.

people want carbon wheels but they don't want tubular tires , hence introduction of disc brakes. Bad design to start with attempting to be fixed
Master50

Posts:238

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06/04/2014 09:45 PM
Right now rim brakes have widely variable performance depending on callipers, rim material, and brake pads. we get bikes with really bad effectiveness to very strong. Just compare a wheel with aluminum brake tracks and the number of different carbon wheels. then add water. If the teams don't all switch to disks at the same time I think we already can cope with the differences in performance. Some guys stop faster then others now.
Wheel compatibility might be a really big deal for the support crews whether all neutral like a local race or mostly team support with neutral backup in pro events.
I think compatibility and an agreed standard is essential to race support. I see thru axels in some quick release system that permits simpler action as the best solution and I guess we will see.
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