Industry views on road discs

[nezumi]

A fellow rider has been trying to convince me on disc brakes for awhile (he has them on his CX bike). I'm not totally convinced as I really don't need that sort if braking power.

But, along with 11 speed, newer things can be attractive. But I do like to swap wheels around (I have 3 sets I use regularly) and this could be more expensive with disc-ed wheels - or am I wrong ?

Like anything new, there are two issues at present with disc wheels on road/cx bikes - availability and standardisation.

As disc brakes become more common, more manufacturers will make disc brake wheelsets and market forces will come in, reducing the cost.

Standardisation is the issue. From my hunting for wheels, having different rear spacings is both problematic and confusing if you aren't sure what spacing your ride uses. It does seem to be converging on a standard of 135mm rear spacing.

I bought my spare wheelset on these forums, second hand. They are Mavic SpeedCity wheels, and so far they have been really nice. I am keen to see more disc brake wheels, and especially more road/CX bike, disc specific wheels (i.e. no brake track) coming onto the market.

[queequeg]

Like anything new, there are two issues at present with disc wheels on road/cx bikes - availability and standardisation.

As disc brakes become more common, more manufacturers will make disc brake wheelsets and market forces will come in, reducing the cost.

Standardisation is the issue. From my hunting for wheels, having different rear spacings is both problematic and confusing if you aren't sure what spacing your ride uses. It does seem to be converging on a standard of 135mm rear spacing.

I bought my spare wheelset on these forums, second hand. They are Mavic SpeedCity wheels, and so far they have been really nice. I am keen to see more disc brake wheels, and especially more road/CX bike, disc specific wheels (i.e. no brake track) coming onto the market.

Agree with that. My CX bike came with disc specific 29er tubeless rims, set up to run with tubes. I couldn't get my standard commuter tyres (or any other standard 700c tyre!) onto the rim (Stans Crest).

In the end, I had a custom disc wheel set built. Mavic Open Pro rims with NSBikes disc hubs (rear hub now cactus and replaced with Deore XT).

When I get around to it, I have some Hope Pro 2 EVO hubs to build up, but not sure how they will handle 12,000km a year of commuting. With the Deore XT hub I can pull it apart, clean it out and repack the bearings. I need special tools for the Hope hubs, plus a supply of new bearings.
I am thinking of getting an n+1, a Sportive Disc bike. I could use the hubs for that instead.

[Strawburger]

True, I didn't think of the discs on 30+ min descents. That's a biggie. I'm small enough to run Alu rims so carbons didn't come into my equation. What's the heat dissapation like on massive descents? Do they create enough heat to cause issues elsewhere near the metal discs?

they can begin to heat the caliper and fluid, but you can go to aluminium sandwich rotors, rotors with aluminium spiders, finned rotors, finned brake pads, or worst comes to worst, go up a rotor size to avoid such things.

Great. Thanks for that response.

[boss]

I've got a roadie/cx bike with cable-operataed disc brakes and I love them. In the real world... Excellent modulation with less hand effort required, confidence when descending really steep stuff and confidence in the wet. For an all weather training bike or commuter, I don't see how you can go past disc brakes.

It's strange though. Hop on a disc brake bike and you're like "Oh, this isn't that different"... until you get back onto a bike with rim brakes, and you wonder where the hell your brakes went.

The only real concern I have about discs is that a ham-fisted rider is going to have a lot more stopping power than traction. Especially in the wet.

[mitchy_]

I've got a roadie/cx bike with cable-operataed disc brakes and I love them. In the real world... Excellent modulation with less hand effort required, confidence when descending really steep stuff and confidence in the wet. For an all weather training bike or commuter, I don't see how you can go past disc brakes.

It's strange though. Hop on a disc brake bike and you're like "Oh, this isn't that different"... until you get back onto a bike with rim brakes, and you wonder where the hell your brakes went.

The only real concern I have about discs is that a ham-fisted rider is going to have a lot more stopping power than traction. Especially in the wet.

my CX has hydraulic discs, and my single speed has a single rim brake up front... i really need to remember which bike i'm on.
you'd be surprised how much straight line traction a skinny tyre has though, i've yet to lock mine up. however i do play it safe in the wet so as not to test our your theory!

[boss]

I've got a roadie/cx bike with cable-operataed disc brakes and I love them. In the real world... Excellent modulation with less hand effort required, confidence when descending really steep stuff and confidence in the wet. For an all weather training bike or commuter, I don't see how you can go past disc brakes.

It's strange though. Hop on a disc brake bike and you're like "Oh, this isn't that different"... until you get back onto a bike with rim brakes, and you wonder where the hell your brakes went.

The only real concern I have about discs is that a ham-fisted rider is going to have a lot more stopping power than traction. Especially in the wet.

my CX has hydraulic discs, and my single speed has a single rim brake up front... i really need to remember which bike i'm on.
you'd be surprised how much straight line traction a skinny tyre has though, i've yet to lock mine up. however i do play it safe in the wet so as not to test our your theory!

I haven't locked mine up yet either, except for when I was testing them out. They do lock up very easily when compared with a rim brake.

But they bite in so quickly, you really don't need to apply much brake in real world situations. I am a bit nervous about getting into a MUST STOP NOW situation, I don't trust myself to manually ABS the brakes... I reckon that will be skid city.

[ldrcycles]

Just change that to "discs" .

[trailgumby]

Sounds like you're really getting uour terth into this ldr

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[queequeg]

I am thankful for the discs on my CX commuter. In wet weather I would not have anything else. I used to chew through rim pads in the wet, even with Koolstop salmon pads. The wear on disc pads is more even, an braking power is only minimally less in the wet.
I have needed that a few times when a motorist pulls a crazy move on front of me.

[Duck!]

Just change that to "discs" .

On what grounds do you assert that discs are bad?

[ldrcycles]

Pad life and susceptibility to contamination, noise and expense of replacement pads. That and the fact that if discs do become the new normal, it will render "obsolete" the frames and wheels that have been perfectly fine for the last century and a bit. I rode a ~25% downhill this morning and the thing limiting my braking was not the power of rim brakes but the amount of grip with road tyres. Discs have pros and cons like rim brakes but IMO the negatives outweigh the positives and they are simply unnecessary.

[Mulger bill]

I am thankful for the discs on my CX commuter. In wet weather I would not have anything else. I used to chew through rim pads in the wet, even with Koolstop salmon pads. The wear on disc pads is more even, an braking power is only minimally less in the wet.
I have needed that a few times when a motorist pulls a crazy move on front of me.

This. I was a long time MTB stalwart, did everything on the one hardtail with nowt but a wheel/tyre swap to suit.

The, back in '07 I got a roadie. First wet ride had the pucker factor right off the clock when I nearly put her under a car that had no concept of what that skinny thing hanging off the side of the steering column was for.

If they only save you once...

[Strawburger]

Quality rims and quality brakes that are maintained pull up in the wet almost as good as in the dry. Ultegra + TWE Alu rims in the wet are way better than koolstops + shimano r500 Alu rims in the dry (my 40,000km experience with this combo).

I can see that discs could be a far better option in the city and for steep descents when training

[boss]

Quality rims and quality brakes that are maintained pull up in the wet almost as good as in the dry. Ultegra + TWE Alu rims in the wet are way better than koolstops + shimano r500 Alu rims in the dry (my 40,000km experience with this combo).

I can see that discs could be a far better option in the city and for steep descents when training

I run ultegra brakes, dura ace pads and dura ace rims and completely disagree. Dry and wet are chalk and cheese.

Contrasted with disc brakes, which perform pretty much exactly the same regardless of water.

You don't realise how bad rim braking performance is in the wet (or dry) till you try discs out. Seriously.

[trailgumby]

I have Swisstop Black pads running on TWE rims at the moment on the roadie. I have to say that while they are much better than Ultegra pads they replaced, they simply dont hold a candle to my 8 year old XTs on the old commuter. And today's discs are a whoooole lot better again.

The roadie is really fun and fast, but once the school holidays are over I think it's gonna be hardtail time again ... until all the 4WD mums dropping their little daaahlings at school realise that spending 2 hours each way in traffic is stupid and public transport is better.

Once traffic settles down to the usual level of insanity in a month or so i might pull it out again.

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[Strawburger]

Maybe my memory is fading, it's been a while since we have had rain up here in sydney

I do stand by my comment though. No doubt the stopping power is better on a disc though.

[queequeg]

I did Akuna Bay (clockwise) on my roadie after about 8 months of exclusive riding on my CX Disc. As I was coming down the hairpins to Illawong Bay, I hit the brakes to slow down and suddenly realised I didn't have discs. There was gravel all over the outside of the curve and I didn't want to lose the front wheel in the turn, so I ended up running into the drainage ditch and then into the rock wall! Nothing major damaged, just a bruise on my shoulder from hitting the walk, and my left shifter rotated a bit (plus some pride, as 3 cyclists coming up the hairpin saw me do it!)
Now when I switch to the roadie I have to remind myself that it takes longer to stop (Dura-Ace calipers with Koolstop black pads).

[mitchy_]

I did Akuna Bay (clockwise) on my roadie after about 8 months of exclusive riding on my CX Disc. As I was coming down the hairpins to Illawong Bay, I hit the brakes to slow down and suddenly realised I didn't have discs. There was gravel all over the outside of the curve and I didn't want to lose the front wheel in the turn, so I ended up running into the drainage ditch and then into the rock wall! Nothing major damaged, just a bruise on my shoulder from hitting the walk, and my left shifter rotated a bit (plus some pride, as 3 cyclists coming up the hairpin saw me do it!)
Now when I switch to the roadie I have to remind myself that it takes longer to stop (Dura-Ace calipers with Koolstop black pads).

hah, the liberties you take with discs is brutal when you dont have them... i have one bike with hydraulic discs... and another has a single caliper up front. i REALLY need to remember which bike i'm riding.

[toolonglegs]

Go to 1m50s ... when I try this with my cantis I just get the dreaded shudder
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[Xplora]

Backwards compatibility kills it for me. I won't go 11 speed right now because I don't want to write off 4 wheels. Doing that to my front wheels as well??? I think a lot of wet weather road riders overestimate how big a part of the market they are. Part Of the hobby is team kit and shiny bikes etc and getting that dirty is off the agenda for most riders. I have ridden in everything and you notice how little it takes to put you on the trainer if you don't commute.

[Calvin27]

Backwards compatibility kills it for me. I won't go 11 speed right now because I don't want to write off 4 wheels. Doing that to my front wheels as well???

I suspect this is the main reason - not performance. I jumped on board (at a premium) because of compatibility with my 29er.

The good thing is that this will be an easy transition for the industry - eventually those rim brakes will wear the wheels need replacing. After that, let's hope they don't think of new standards (how does 142x12 TA sound on a road bike?).

[cyclotaur]

I can see the point of discs on mtb, CX/gravel bikes and especially year-round, all-weather commuters, but for the pure road bike (used only for road rides) I think there is little actual benefit over existing rim brakes, with the possible exception of the carbon rim/wet weather issue. That won't apply to me because a) I won't ever buy carbon rimmed wheels, and b) I can ride when I want and avoid bad weather as much as possible.

I ride a 10-speed CX bike with canti rim brakes and, occasionally, an older 9-speed road bike. I may get a new 11-speed road bike eventually. I already swap my 4 wheelsets/cassettes around quite a bit and it's no trouble. My newest set is 10/11-speed compatible. Swapping wheels is no big deal at the moment, but discs on a new bike would limit that for no real benefit to my road riding.

Others views may differ but I think my situation is fairly typical of a lot of recreational (ie. non-competitive) riders.

[mikesbytes]

I have hydraulic disk brakes on my mountain bike and they work pretty good.

As I don't do the huge descents that TLL does in France I don't see a reason to use them on my road bike. In my races the brakes are used to adjust the speed, so one braking system vs another boils down pretty much to aerodynamics and the disk brakes aren't there yet aero wise.

What was interesting in the aero test (thanks NoBody) was how much difference cable routing made

[AUbicycles]

Queequeg, I picked out your teeth from that rock wall today.

I am for discs in Road bikes and not 100% convinced on some of the argument presented against them. But one thing is maintenance, a bit more work or complexity than rim brakes. I looked at the video on bleeding sram road brakes and thought, that is something I would have to watch a few times.

Discs are an obvious solution for carbon rim issues. (or hybrids).

[igstar]

What is the impact on forces on spokes when breaking at rims vs disks? Would wheel spoke count on roadies need to be beefed up as well as a result?