what would you need to adopt Disc's on your Road Ride?

Discuss light weight issues concerning road bikes & parts.
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by mjduct

I was thinking about this as I have made the leap of faith into the Disc world. I have a titanium bike coming for a backup/ foul weather/ super long rides where the Cervelo R5 beats me up too much. I'm going to run fairly large tires (maybe even the new 28mm Sector Tubeless tire) so this will be more of a comfort bike than an out and out gram counting weight weenie/ race bike.

What would you need to make the jump? esp for a race bike? (Besides UCI adoption, in my mind they've done more to cripple the sport than anything else)

I really don't think weight is a concern, because most of us are having to add weight to our rides to meet the limit (once again UCI stifles innovation)

some things that I've thought of are:

+ floating pads/ discs something to provide a self centering mechanism for wheel changes
+ more action from the levers/pistons to allow for easier setup/ interchangeability
+ some revolutionary technology in rim design that can only be used without the brake surface-. super aero, super light, or some big game changer.

Others I've heard:

-make it sleeker/sexier
-lighter weight
-hydraulic for modulation/power (seems to have another set of issues)

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by deltree

I really wouldn't... but if Cervelo, 3T and Magura could integrate a hydraulic rim brake into a fork (like the THM Scapula F) and drop the rear brake inside the stays that would be amazing.

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by Calnago

I'd have to be riding a road bike in very foul weather a LOT to consider discs on a nice road bike. It would have to have clearance for larger tires. Essentially it would be like a disc braked cyclocross bike but with road bike geometry, a C59 disc frame but with clearance for fenders for example, which it does not have now. Last fall I rode a cross bike on the road just to try it out for the purpose of a dedicated rain bike, but I disliked the handling so much that I would rather just continue to deal with mounting fenders on the road bike. But aside from the tire clearance with fenders, the real trouble with fenders on the rim braked road bike is that it just ends up dripping all the crud right onto your brakes and rims. Discs solve that. But quite frankly, that's the only real world advantage to them that I see, on a high end road bike. While your wish list of dedicated rims with no brake track is valid, getting them lighter is another matter simply due to the fact they actually have to be stronger in the spoke area to withstand the forces of the braking action getting transmitted from the hub to the rim. So, in fact the rims have to be made stronger, not weaker, in that area. And the added frame reinforcements for the brake mounts just add up to a less pleasing aesthetic in my mind, at least when it comes to the highest end road bikes.

So, to answer your question again... a lot of unpleasant rain riding is what it would take, for starters. Otherwise, I'm happy with the current crop of rim brakes and wheel choices.

Commuters, etc. are a different matter, and you specifically asked about "race bikes'.
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by Pharmstrong

I've read that pads/discs can rub. That would annoy me. If that isn't an issue, then I'll be having a Di2 group with hydraulic discs on my next bike.

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by Colin

Pads/disc will rub if it's not set up properly...but so do rim brakes. I've yet to have any rub issues with Shimano (mountain bike) disc brakes, and am pretty confident that they'll do the road disc's just as nicely as the MTB brakes.

Honestly, I'll be pretty tempted to convert as soon as Shimano releases their disc road group!

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by jmilliron

Doesn't rain much here. I'd never consider it on my race bike.
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by pushstart

My next road bike will be disc-brake equipped. I have been riding discs on my commuter and cx bike for awhile now. The stopping is just so much better -- better modulation and braking consistency (esp in wet, of course). And much better pad life. I will feel much happier riding carbon clinchers when there is no heat issue and when my brakes still work well when it rains.

Obviously rim brakes are satisfactory, but discs are so much better at the braking task that I don't know why I wouldn't want them on my next bike (assuming it doesn't need to be UCI legal). The centering feature would be nice for changing wheels. Don't hydros auto center? I swap wheels between road and cx but I built them on the same hubs, so no adjustment needed.

As for the argument about rims needing to be stronger at the spokes, this seems to be more theory than practice. Lots of road rims are offered on disc builds (e.g. velocity, Stans) without any changes to the rim. (Did Zipp change their rim? I don't know.) You probably do need more spokes, though. And they need to be crossed. That is true.

We need more lightweight disc hub options. Don't need burly mtb hubs for road use. I have been using BHS hubs, which aren't bad, but a lot heavier than the road options.

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by mattr

Colin wrote:Pads/disc will rub if it's not set up properly...but so do rim brakes.
TBH, rubbing rim brakes is generally a doddle to fix, 30 seconds with a couple of allen keys and you are done until you next do a major change.
Rubbing discs can be a pain in the arse and take ages to fix involving draining oil, jiggling and lubricating pistons, swearing at things until its done, then popping a wheel out and back in again and you have to start all over again. (dependent on the actual model/brand of brake.)

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by thisisatest

With road bikes and their reduced need for absolute braking power, it would be easy for the brake guys to spec a slightly larger master cylinder or smaller caliper pistons to increase throw, and a piston seal that retracts farther. Then you have more pad/rotor clearance.

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by parsnip

mattr wrote:
Colin wrote:Pads/disc will rub if it's not set up properly...but so do rim brakes.

Rubbing discs can be a pain in the arse and take ages to fix involving draining oil, jiggling and lubricating pistons, swearing at things until its done, then popping a wheel out and back in again and you have to start all over again. (dependent on the actual model/brand of brake.)

I have some base tektro disc brakes on my commuter which very definitely do not rub every time you take the wheel out. When they occasionally do rub it takes maybe 30 seconds to fix each one, you just loosen the calliper, squeeze the brake lever and then tighten the calliper again. I have been using the same pads for like 3 years and they still brake better than the brakes on my road bike (alu rims) and in that time I've only had to fix rubbing callipers once. I still wouldn't have them on my road bike though, too fugly.

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by mjduct

the last few posts are exactly the type of thing I'm looking for...

3 years ago we were saying "Carbon clinchers would check all my boxes if..."

Now alot of those things have been worked out, and carbon clinchers are safer, lighter, and more aerodynamic than ever.

I think another issue with the adjustment is CAN A TEAM MECHANIC DO IT WHILE HANGING OUT OF A CAR WINDOW????

I know on my current BB7's to adjust the inner pad you have to go through the spokes, not possible while riding down the road at 20+mph

I know this is one of the big issues with moving the rear brake below the bottom bracket for aerodynamics... you can get to it to adjust it on the fly.

so maybe add this to the list:

+having easily accessible/externally adjustable calipers

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by dgran

This is one innovation I'll probably sit out and I'm pretty keen to try out new things. My understanding is that the width of the rear stays has to get a little larger to permit disc brakes in the rear. I'm game to hear if I'm wrong about this, but a change in frame geometry is a huge departure and disincentive to adopt the change, or at the least let it play out for a few years to let it standardize more. I do like how disc brakes will make carbon rims feasible. No matter how many vendors claim that they have made carbon surfaces effective for braking, standard surfaces or disc brakes are superior to any form of braking against carbon rims.

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by sigismond0

Yessir, 135mm is the new standard for rear stays with discs. 110 in front as well, unless I'm mistaken.

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by mjduct

I haven't heard the 110 in front, but I don't think it is a terrible idea, but 135 is the go to in the back, even though some manufacturers are still makeing their disc frames with a 130mm rear hub spacing. (others are going 132.5 and letting people stretch/compress it!)

also Foundry is putting a 9mm thru-axle on their forks. (If their road disc bikes ever come to market) That should stiffen up the front end significantly. so I see the front end as a "variable" in the entire equation and I don't think it's out of the question for it to widen up in the next few years.

As much as we complain about 17 different bottom bracket standards, and a rapidly growing number of headset dimensions/designs. I think that we will have to equally worry about hub widths in a few years time. Kinda like cars... "lets make them so complicated only a professional mechanic can deal with them for a hefty fee" mentality.

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by maddog 2

I'll be going discs on my 'good' carbon bike as soon as somebody makes a decent, affordable frame.

I already run discs on my ti commuter/trainer and would never go back to rim brakes. Discs are just better in every way.

So to answer the question......... I'd just need a decent, affordable, handsome carbon disc frame*.

*so that rules all the current players for me;
Colnago - too expensive and lecky-only
Parlee - silly money
Volagi - not handsome
Spesh - ditto
Eastway - ditto
various carbon CX frames (Felt, BH, Fuji...) - just not quite there geo-wise
various proto frames that aren't being made (Canyon, Trigon...)

by Weenie

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