9/18/14 4:58 PM

So we have a trickle up to the pros instead of the other way around for a change?

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The UCI will run Paris-Roubaix as a road disc test event in 2016, according to sources within the UCI and the cycling industry. The governing body was originally shooting for 2015, but Campagnolo’s slow movement toward discs and SRAM’s recent recall moved that optimistic timeline back. Even 2016 may be overly optimistic."

http://velonews.competitor.com/2014/08/bikes-and-tech/stopping-progress-debate-hydraulic-disc-brakes-pro-peloton_340905

9/19/14 5:30 PM

I suspect more crashes. yep....

If the weather is crap they will quickly reach the traction limits of the tires and washout in hard braking conditions. Breaking power will far exceed tire traction and "boom" go the disk riders.

Rim brakes force the racer to ease into braking conditions in horrid conditions.

9/19/14 6:27 PM

I wonder if that is what happened when MTB races went to discs?

9/19/14 6:48 PM

Why do they care if some manufacters are late getting their product out? Let those that want and have disc ride them.

9/19/14 7:32 PM

Going to bring a whole new dynamic to neutral service wheel change times...

9/19/14 7:43 PM

quote:

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Why do they care if some manufacters are late getting their product out? Let those that want and have disc ride them.

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9/19/14 8:36 PM

P-R is almost unique among the Classics as it is nearly dead flat so the braking differential and the possibility of red hot discs are minimal.

9/20/14 5:58 AM

MTB races.

Nope, the tires have much greater traction and they are not on slick cobbles or in a bunch. Apples to pears WRT the racing environment.

9/20/14 7:40 PM

The worse the weather, the safer the riders will be with disk brakes. The reason? Better modulation and consistent braking, regardless of the conditions. A lot of crashes in wet, low traction conditions are caused by rim brakes that have little effect initially, then come on all of a sudden once the rim is wiped dry by the pads, locking the wheels and causing skids. That doesn't happen with disks.

To answer your question about MTBs, no there wasn't a big increase in crashes. Having ridden cantilevers, V-brakes (generically known as "sidepulls") and disk brakes on MTBs, I can assure you that there is absolutely no comparison between either rim brake and disks; disks are vastly superior , period. They are dramatically safer too, as the braking is completely predictable, no matter what the conditions are.

As for the tires having greater traction, that's simply not true. There may not be cobbles off-road, but there are slick roots and wet and/or mossy rocks, in addition to the variety of low traction, soft surfaces. From a technique and skill perspective, MTB braking is much more demanding than road braking. The only area where road brakes are more demanding is in heat dissipation requirements for long, fast descents.

While some people seem to be all worked up about the possibility of riders getting burned by hot rotors in bunch crashes, I strongly suspect that the reduced number of crashes due to superior disk brakes will more than offset that danger and there will be a net improvement in rider safety.

9/20/14 9:41 PM

quote:

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Breaking power will far exceed tire traction and "boom" go the disk riders.

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9/20/14 11:39 PM

Well, my last post in the BB7 VS TRP Spyre thread shows my feelings on the disc experience in a panic stop.

9/21/14 4:55 AM

It is the less powerful initial braking that i say prevents some washouts on slick surfaces. The rim cleaning time forces a more conservative application of the brakes while the disk is wham, always on and the rider gets a surprise from the tires because they become complacent.

9/21/14 8:07 AM

What you say is absolutely untrue; disk brakes are very easy to modulate. They are definitely not an on/off switch, as you describe.

If you've actually experienced what you said, it's probably due to the bad habits that rim brakes forced you to adopt, due to the fact that in wet conditions, you have a grab a fistful of brake in order to get any response. With disks, one finger braking is all that's necessary, regardless of conditions. Since they are 100% predictable, you squeeze them progressively until you achieve the desired/required degree of braking. With experience, this becomes second nature, just like it does with the disk brakes on a car.

I saw multiple interviews with pros during the Tour where they lamented about how hard it was to brake in wet conditions, especially with carbon rims. I remember one stating that they have to brake "full on" every time and Van Garderen blamed his crash on the roundabout on the fact that his brakes grabbed suddenly when the pads cleared the water off the rims.

It seems to me that your theory of braking is exactly the opposite of reality. FWIW, my own experience bears that out. I can think of few more alarming feelings on a bike than applying the brakes, having nothing happen, then wondering when/if they will grab and whether it will be in time to avoid crashing. That simply doesn't happen with disk brakes; you get the same braking every time.

Last edited by Brian Nystrom on 9/21/14 8:21 AM; edited 2 times in total

9/21/14 8:09 AM

dp

9/21/14 11:58 AM

"disk brakes are very easy to modulate. They are definitely not an on/off switch"

Two weeks ago I posted about a nose wheelie and a front skid on the Scott, Dura Ace 10 speed rim caliper brakes. Faster speed but never actually fully stopped either. Friday very similar severe panic stop with the Disc Roubaix to a complete stop so as not to run over the rider on the ground I was directly behind. Stop was more controlled with no skid on the Roubaix. More concerned about a rear end hit form the guy behind me

So in my limited road disc practical experience thus far, I also have issue with Erik's theories and disagree vehemently.

Like to see how/if hydr road disc might be even better. I say that because my 29er Juicy Avids are superior in all aspects to the cable discs I have had on a few MTBs.

I also think the two piston TRP/Spyre modulation is hugely better than all the BB5-7s I've used. I have used BB7 on the Roubaix initially and ridden the Poprad disc with the BB7s on the road as well.

The CX-75 I cannot say I could test/comment on for comparison as on Elaine's 49CM Ruben Disc, I could not ride it per say.

9/21/14 12:30 PM

How does moisture affect discs? Say if you're riding in the pouring rain, or if you have to pass through BB-high water?

9/21/14 12:54 PM

"moisture affect discs"

I have no experience to comment. Other than to say off road you have better, more, and faster initial response in bounds with wet conditions. However, I do not ride intentionally in wet, so limited situational experience.

9/21/14 1:34 PM

I've ridden disc equipped mtn bike in the rain. It's still a lot better than rim brakes.

I would believe the same needs to happen: the water needs to be wiped off the disc surface before true braking happens. Except in this case, there's a lot less surface to be "wiped dry", so it happens a whole lot quicker.

9/21/14 2:05 PM

The only difference water makes in my experience is sometimes my Avid BB7's would get noisy at first and squaak(is that a word?) . Braking effectiveness was not altered. I've put them through incrdibly bad conditions on a mtb and they were always wonderful.

However, I think they take more than they give on a road bike.

As far as Paris -Roubaix, I doubt that the riders brake much except for a few low speed corners and if somone crashes in front of them.

9/21/14 2:12 PM

"I think they take more than they give on a road bike."

I am starting to think not after miles on the Roubaix, especially with the TRP brakes now.

But admit leaning that way initially. Even thinking I maybe should have got the non disc Roubaix for 100.00 less. Mostly weight being the issue. But with a frame as stiff as this SL4 and having hit a few good hills and not sensing any issue with it @ 22 lb even.
I will take stiff and 22 lb over not and 16-18lb. [assuming I am correct 'stiff' being the component] The Scott of course is both light and stiff, I doubt I climb better or faster on it.

9/21/14 5:27 PM

yes, I have ridden an MTB with disks but I must admit that it was 12 years ago and no it did not modulate well at all.

9/22/14 6:36 AM

quote:

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Except in this case, there's a lot less surface to be "wiped dry", so it happens a whole lot quicker.

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9/22/14 7:27 AM

" If disc brake work better in the wet it's because the pad pressure is higher and cuts through the water film faster."

and the fact that the rotor accumulates less water to begin with -- rotor's about a foot above the wet road surface accumulating less water/grime in general. unlike a rim which is continually splashed directly by water on the road and getting doused by water picked up and running off the tires.

with a disc, 1 rotational wipe and it'll be pretty much clean and dry for solid braking.

with a rim, as the brakes wipe the rim dry...a half-rotation later its back down to the road to get replenished with a fresh load of water.

9/22/14 9:42 AM

I've noticed that wet disks on my *car* feel significantly more grabby than they do when dry, though that's likely due to the materials involved (don't ask me what they are). It appears that doesn't happen with bike discs, which is good.

9/22/14 10:57 AM

when the pads first hit a wet rotor, they slip more than when they're dry, and then when they dry they grab...so the delay in stopping = grabbiness.

this actually speaks to how well bike discs are removed from water exposure, being so high above the ground.

a car's brake rotors are constantly doused in water from all the road spray from the car, and wheels and splatter.