Iceberg Ahead Captain
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| Iceberg | Disc Brake |
It's coming. One way or another, because you, yes you, the public, demand it. Hydraulic disc brakes have been so effective for mountain bikes, we must have them on road bikes, now!
Yes, hydraulic disc brakes are the option for lots of different kinds of vehicle. In the biking world, we know the positives for mountain bikes far, far outweigh any drawbacks.
No, road bikes have worked very well with these nice light calipers pinching an alloy rim. Need more braking force than a normal dual pivot caliper? Well, there are these cantilever brakes, tourers, cyclocross and early mountain bikes all used them.
But, standard road calipers have to be set up pretty damn tight to perform at their best. Hydraulic brakes, by comparison, are much more "fit & forget".
Will they work on road bikes?
Oh heavens, yes. So why don't we already have them?Discs, calipers, levers
Calipers are a well known quanitity, as are levers and discs and pads (after all, we've been using them for years on mountain bikes, what could possibly be different about a road bike...). SRAM are just about there this year, with the Red groupset, announcing a full hydraulic lever/shifter, and matching caliper.
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| That's a hydraulic caliper up there, that is. |
The problems will come from the rest of the bike. Mainly the wheel and the fork.
Wheels and Forks
- Roadies don't like heavy wheels with lots of spokes and that's just the kind of wheel needed to resist all that braking torque being applied through the hub.
- Roadies don't like heavy forks, and that's what is needed to resist all that braking torque being applied at the tip of one fork leg.
- Roadies don't like metal forks, and that's what is need to aid in cooling down the caliper.
- Roadies don't like heavy stuff full stop, and a bigger (heavier) disc will run cooler and won't warp as easily.
- Standard QRs, mountain bikes are slowly going the 15mm (or 20mm) axle route to avoid any problems with the disc vibrating the skewer loose (see this out of court settlement).
So there's a few problems to solve here.
Long, fast, descents = lots of heat. Mountain bikes have these huge chunky suspension forks made of lots of metal which helps get rid of the heat generated by the disc & caliper. A carbon road fork won't get rid of nearly as much heat, and boiling brake fluid = no brakes. So we'll need a nice chunk of metal on the fork to spread the heat around.
Braking torque. The bike has to deal with the torque generated by the braking action. Mountain bikes, yes, nice big chunky forks again solve that problem. Road forks?
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| Whoops! courtesy of Rodriguez Cycles |
So that nice light road fork is going to have to get a bit more chunky, to deal with these problems.
Step forward Canyon with their 'one small disk per side' idea.
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| One small disc per side of the fork, Canyon's Project 68 http://www.canyon.com/_en/technology/project68.html |
That sort of solves the issues of fork flex (torque is halved, and distributed across both fork legs). And a nice bit of metal to help get rid of heat. Non-standard hub, non-standard discs...
Lastly, the axle standard. QR15? Can you imagine the roadie market adopting a monster mountain bike axle? Besides, 99% of the bike world doesn't even accept the physics behind the "disc brake + dropout + standard QR" problem.
Will it be worth it?
Up to you, bike buyers, you're the ones with the cash.
Personally, I'm not swapping any time soon. Regular calipers cost squat by comparison, I ride aluminium rims, regularly check & adjust my brakes, keep my wheels trued, and hence get perfectly good braking from my current setup. I'm the far side of 200lbs and have never felt unsafe riding up and down mountains. Brakes don't work quite so well in the wet, I ride slower. Yay, me. I realise I'm not completely representative of the bike buying market though, and a lot (read: practically all) of people like the idea of brakes that don't break.
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