ufgood

I think that the jury's out until there's a range of brakes designed from the ground up for road racing. As people have been saying, the teeny contact patch provided by road bike tires is easy to skid with (even single pivot) rim brakes. However, if a smaller, less forceful disc setup were built with road riding in mind, one might see some real advantages of it, enough to start offsetting the added weight needed at the rim now.

mic2377

All of the naysayers here just need to live in WI and ride during the winter. suddenly the utility of disc brakes is immediately apparent.

I have a 'cross bike with discs, and it is WONDERFUL. Pads last forever. I have 2 seasons out of one pair of front organic pads. That is amazing longevity. The modulation is great too.

They also don't really cost that much, or even weight all that much. The weight penalty can be minimized if you pick the right parts.

I believe that they will certainly catch on for cyclocross, as soon as the UCI makes them legal for elite racers. There is an obvious need in that circumstance. Alot of those light canti's on racing cross bikes just SUCK.

merlinextraligh

I just don't see the need, other than cyclocross, commuting in a very wet weather environment, and loaded touring perhaps.

I debated putting a disc brake on our Tandem, (where you're stopping a lot more weight, at higher speeds, and rim overheating is more of a concern.) Having done descents on Everest Challenge, Brasstown Bald, Hogpen, Paris mountain in the rain, and a fair sampling of the Blue Ridge Parkway, I've concluded that even at a Team weight of 335lbs, Dura Ace calipers were more than adequate.

giantcfr1

Just as a matter of interest, which brand pads are you running? I had avid pads and they were sh1t. They lasted less than six months, and here in Japan cost a small fortune. (2750 yen a pair)

I changed to "cheap and nasty" BBB, and they are going great and cost 1700 yen a pair.

cyccommute 

They all already have discs. Rim brakes are disc brakes...just with larger rotors.

As for their benefits, I've had two disc brake systems on mountain bikes and I don't find either to be a huge advantage over rim brakes. Tolerances are much closer in discs so it's easier to get them misaligned and end up with brake drag...much worse then added weight Not all disc hubs are equal either. Some need to be remachined to get a parallel face (Park even makes tools to do this). Wheel removal and installation can mess with alignment necessitating a centering of the caliper...not necessarily a simple job.

As for modulation, I have yet to experience the 'superior modulation' of discs. They are digital..1 or 0 ...on both of the bikes that I've had. The Juicy 7s on my current mountain bike are extremely touchy. In fact, it's recommended that you run one sintered pad and one organic to reduce the grabbiness of the Juicy 7s. There is a very fine line between slowing and full lock up on these brakes...not something that inspires confidence when flying down a trail filled with babyheads

As for being needed for loaded touring, I have cantilevers on my touring bike which regularly carries me and 50 lbs of food and gear down mountain roads at well over speeds that are stupid (40+ mph) and I've never felt that the brakes wouldn't stop me.

tubescreamerx

Just to remind you how badass they LOOK as well... (courtesy of MIN)

merlinextraligh

fixed.

somewhere on the Continent Euro is exploding in frustrated rage.

markhr

old thread that needs updating but it's a start

https://www.bikeforums.net/showthread.php?t=368115


trek portland - https://www.trekbikes.com/us/en/bikes...land/portland/

cannondale cross xr7 - https://www.cannondale.com/bikes/08/c...del-8XR7C.html

Brodie Ronin '08 - https://www.brodiebikes.com/2008/2008_bikes/ronin.php
Brodie romax '07 - https://www.brodiebikes.com/2007/2007_bikes/romax.php
brodie ronin '07 - https://www.brodiebikes.com/2007/2007_bikes/ronin.php

lemond poprad disc - https://www.lemondbikes.com/bikes/cross/poprad_disc.php

rocky mountain sherpa - https://www.bikes.com/bikes/2007/TOURING/sherpa-10.aspx

kona sutra - https://www.konaworld.com/08_sutra_w.htm

orbea diem drop disc - https://www.orbea.com/ingles/interior...ilia=6&gama=13

focus cross disc - https://www.focusbikesuk.com/focuscyc...cross_disc.php

devinci caribou2 - https://www.devinci.com/10479_an.html

raleighusa sojourn - https://www.raleighusa.com/items.asp?deptid=5&itemid=427

rei novara element - https://www.rei.com/product/744808

co-motion mazama - https://www.co-motion.com/mazama.html

rocky mountain Solo CXD - https://bikes.com/2008_preview/2008_preview.html

rotwild rs1cx - https://www.rotwild.de/en/ (street bikes section)

fixie inc. pureblood - https://www.cycles-for-heroes.com/200...pureblood.html

maxx roadmaxx custom (you choose the color and parts at the LBS and the factory puts it together, i.e., not a custom frame) - https://www.maxx.de/frmain_bikes.htm (road - roadmaxx custom)

Salsa la Cruz - https://www.salsacycles.com/laCruzComp08.html

...and, yes, I should've taken the commuter crap off for the race mode (sans PowerCranks) picture

BarracksSi

After getting stuck with riding through mud & silt and scraping the crap out of my CAAD8's Fulcrum rims, I decided that I'd never take it out again when it could be wet and instead use one of my disc-equipped bikes.

Really, it sucked.

"We've been using rim brakes for a hundred years, why change now?" Okay, yeah, maybe we should ditch the rim brakes and go all the way back to rubbing spoons against the tires themselves. It worked back then, didn't it?

No real problems with discs here. Wheel swaps are even easier than anybody seems to complain about.

nycphotography

Someone touched on the reason...

The real problem with disc brakes is that it moves the application of torque away from the rim and to the hub. Now the wheel, the hub, the fork, all have to be built much stronger. The weight isn't just the caliper and rotor... its all the other stuff that has to be way stronger too.

Now add on top of it that stronger forks and seat stays are going to be wayyy less compliant and will likely pummel you to death on rough roads, which is an area where massive r&d dollars are being spent right now, and you see why the consequences of disc brakes are far greater than just a few ounces for the parts.

Dago

In my opinion disc brakes are by far superior, the only problem CURRENTLY is weight but that will disappear when manufacturers start making road specific disc brakes.

Havent seen this one linked in here; a Canyon prototype bike designed for racing (weighs a tad over the UCI limit of 6,8kg): https://www.canyon.com/_en/technology/project68.html

markhr

Thanks for posting. Is it just me or are the brifters in "brake open" position?

edit: also just noticed the front rotor is on the "wrong" side - possibly helps prevent the mechanic making a quick road side change from getting branded?

Kastnerd

They are using Dual rotors up front. The says 125mm size rotors, To put stress on both legs of the fork.
Im not sure if this is necessary as 29er bikes with carbon forks and a single 180mm rotor work just fine. Look at the White Brother fork, and Niner has a prototype fork at interbike that might work for road as well.

markhr

Nice! Fork!

Yeah, I went down the CF disc fork for the new build - when it turns up(when I can afford to pay for it ).

The On-One 29er CF fork is also very good and, unlike other manufacturers' current models, doesn't have a rider weight limit.

Dual rotors on sport bikes I understand (heavy vehicle, high speed, rapid braking, fork shudder, etc) but I really can't see the point of dual rotors on bicycles. Any automotive mechanical engineers care to comment (show your working )?

stapfam

Disc brake work and very effectively-

So any of you thinking about changing to them-Remember- The disc caliper is mounted on the Chainstays on the rear and on the fork at the front.

Both of which will have to be strong enough to take that extra braking force.

And on the front wheel- You have to think of a bolt through axle to stop the front wheel being twisted out of the dropouts under hard braking.

So disc brakes only weigh a couple of lbs extra? Think again. Mine weigh 2lbs each and I reckon the strengthening of the frame and forks will put on another couple of lbs.

Kastnerd

Id like to know how they used hydraulic brakes with road leavers.

BarracksSi

I'm no engineer, but their reasoning makes sense.

About this:

I have yet to experience such a problem on any of my three bikes with quick-release axles and disc brakes.

BarracksSi

Prototype levers.

Dubbayoo

Let's not cloud the issue with facts.

doppiodan

With all the optimization of frames and forks on road bikes for your favorite cliche and mine (lateral stiffness and vertical compliance), discs don't make much sense on a dedicated road bike. I'm not talking about all-arounders, CX bikes, commuters, low-riders, etc. Take a look at a Cervelo R3, S-Works SL2, Roubaix SL2, etc. and check out the massive differences in chainstay vs. seatstay cross-section. iImagine how much of the ride-tuning would be negated by moving brake reaction forces to the lower fork, in particular. On both my steel and CF road bikes, there's a significant amount of fork tip action that keeps the ride smooth.

Yes, discs rule in wet weather. Yes, they rule on MTBs, but MTBs also have 135mm rear spacing and totally different demands.

I'm down with discs on everything but a dedicated road bike. They all use higher-volume tires that swamp the frame and fork characteristics. That said, I wouldn't be surprised if discs take over in the next 10 years.

markhr

AFAIK the DB twisting the QR open is a myth. I've also never had that problem with mine.

markhr

There used to be Magura HS22 rim brakes with road type aero levers which can be used with their low pressure systems, e.g., magura julie(?) discs. Magura discontinued the aero lever part due to poor sales.

If you mean brifters with hydro brakes then I have no idea.

roccobike

I have Avid BB5s on my dual suspension FSR XC mtb. My Rockhopper has Shimano XT V's with Koolstop salmon pads. While the disc brakes are slightly more powerful than the XT V's, the only real advantage is the superior modulation that comes in handy when scrubbing off speed on a tight single track. V's tend to be a little grabby where discs are smoother, more predictable. But that's the whole point, I use my brakes constantly when riding a technical single track to scrub off speed in the tight corners. I just don't ride that way on a road bike. When riding solo I rarely use the brakes except for traffic signals/signs. When riding with my club I use the brakes a little when riding in the back of long pace line, but I don't need discs or better brakes to slow down so that I don't cross the wheel of the person in front of me.
Is there a good chance discs will show up on road bikes? Well IMHO, I never thought you'd find them on MTBs under $500, but now they're on WalMart bikes. The low end discs might be junk, maybe less effective than V's, especially good Vs. But the public wants them cause they look good on a mtb. I think its a huge waste of money on a road bike, but if they're marketed correctly, I'd sell my stock on dual pivot caliper brakes. Cause some folks will be convinced they "need" disc brakes.
EDIT: Discs might work well for commuters, in that instance, any advantage could be life saver, so I can see that appication.

BarracksSi

Yeah, I see what you mean;

For the rear, maybe the fatter chainstays would do just fine for mounting a brake caliper.

And, for the front, part of the idea behind the double brake setup is to enable fork legs that are about as thin as regular forks. Since it's not relying on just one fork leg to take the load, and each brake is actually generating less force since the real braking power is based on the tires, they can both be made thinner and more compliant.

Anyway, I'll give it time to see how it turns out with some real-world use. Some ideas work, some don't, but nobody knows for sure until they try.

bikeM3987

OK, there are some obvious misunderstandings here... safety.

The reasons that you can't have disc brakes in cross is the same reason you can't in road. Those things get really friggin' hot, and they are already sharp has hell. It's like a little circular light-saber screaming murder me in every crash that could happen. We won't see them on racing bikes until they are safe, which probably will never happen.

Edit: Another thought... You can only get so much braking power on a .5" wide tire. You could put some 13" brembo's and you still are limited by smaller tire area...