JakiChan

I bought my little hybrid at the end of May. I told myself that when/if I did a century I'd be ready for a road bike. That happened at the end of October. So it's shopping time!

I've been looking at mechanical Ultegra endurance bikes, and one shop I really like was suggesting that I might like the Roubaix Expert Disc...which isn't out yet. The reasons given were all the usual ones...better stopping power, better modulation, etc.

We're not sure how much it will add to the cost of the bike at this point. The mechanical Ultegra bikes I've looked at are all around the same price point. (Roubaix, Domane, Synapse, etc.) But assuming the disc bike is still in my budget I have to ask: This is gonna be Specialized first road bike with disc brakes. They are still pretty uncommon on production bikes. While I like being an early adopter in some things I'm wondering if I should just hold off on that for now and stick with traditional brakes. Would you jump in now, or wait?

giantcfr1

They've been used in cyclocroos races for quite a while now. What could go wrong?

I saw this at a bike show a few weeks ago and it looked pretty snappy.

antmeeks

You won't ever see very many roadies on disc brakes until someone wins the Tour on them, lol.

nastystang

Colnago C59 disc, I will take two please.

mustang1

i would wait for them to get mainstream.

merlinextraligh

I like my 622mm discs.

ddeadserious

Like giantcfr1 said, they've been used on cyclocross(and mountain) bikes for a while now. It's not like it's new technology that nobody knows how to implement. Adapting disc brakes to a road bike is nothing special or crazy. If you want disc brakes, get one and fear not.

merlinextraligh

1) they've only reently been used on cross bikes.

2)there have already been issues using disc brakes sized for cross racing on road bikes.

Disc brakes on road bikes are not a mature product, with lots of stuff to sort out. There's work to be done to get rotor size right, optimally designed forks, disc specific road hubs and rims etc. Early adpoters will help pay the cost as the bike industry sort this stuff out.

If discs on road bikes catch on, its almost certain that disc brake equipped road bikes will be much better 2-3 years from now than the first attempts this year.

merlinextraligh

Do you race cross? The demands on braking for cross is different than descending mountains on a road bike. Disc brakes sized for cross can, and have melted down inuse on road bikes.

coachboyd

This is a very good point. Disc brakes makes sense for cross where there is a lot of hard short braking (and also wet conditions and mud). For road riding your wheel is acting as a 633mm brake rotor so the demands of braking are minimized as much as possible. When you swap to disc brakes you now have a 140 or 160mm rotor trying to stop the 633mm wheel. It puts a lot greater demand for braking placed on the rotor which can build up a lot of heat on prolonged braking applications (road bike on steep downhills). The pads can glaze or in the event of hydraulic disc brakes the fluid can boil and once it does and you get a little air in the line your brakes completely go out. . .and if you are flying down a hill there is nothing you can do to slow yourself down besides unclipping and putting a foot on your tire like when you were 8 years old.
I think for mountain bike, cross racing, and some wet weather road riding disc brakes have good applications, but they aren't necessarily the answer to long steep descents.

SlimRider

The average racing road bike does not need disc brakes...

Bah Humbug

If you're thinking of the article I am, the writer describes riding the brakes on a long descent. It's quite possible to overcook rim brakes doing that as well.

bonz50

I understand what you're getting at, but it isn't a good analogy about brakes in any way.

big john

I sometimes ride with a guy who has a Volagi and he is very happy with it. He does a lot of mountain riding, but he is a small guy.
I think his Volagi is lighter than my Seven, btw.
As to long steep descents, I'm over 200 pounds and caliper brakes do fade sometimes. I've also had glueless patches blow off because of the rim getting hot.

Nachoman

I've been running a rear disc brake on my tandem for years with no issues at all.
The stopping power seems better than my dura ace with swiss stop pads.

himespau 

I've always thought those Volagi's looked cool. Plus, good on them for surviving the lawsuit from the big red S.

I wonder if rotor heating can be avoided (or at least diminished) with good technique of trading off between front and back brakes when trying to bleed off speed on a long descent. Or if the OP even does a lot of riding where long steep descents is even an issue.

giantcfr1

No I don't race cyclocross, I have merely watched my friends race them here.
I do though regularly use discs descending mounatins at speed on my bike, so I will note your warning of them melting down. Best I tell my friends here too about this, as they too use discs descending the mountains around here at speed without this knowledge.

coachboyd

Swapping back and forth between front and rear brake is the worst thing you can do. when you hit only your rear brake you don't do anything to really slow you down but you build up the heat. Then you are relying on the front to do all of the stopping. The best braking technique for all wheels is to be on the brakes, then off the brakes. Grab both at the same time and brake fairly hard, then release (think 4 seconds on, 4 seconds off). I always grab both brakes at the same time. This is modulating the brakes.

Rootman

I think it's simple, if you want it then GET IT. Disc brakes on bike are pretty much just starting out and the NEED for disc brakes on a bike is not as marked as it is in a car, you are stopping a multi 100 pound vehicle as opposed to a multi TON vehicle, so the advantage is not THAT large. This all goes out the window if you're headed into a dicey situation and need to stop NOW and disc brakes MAY offer a bit of an advantage. That being said disc brakes appear to be superior and offer more control than rim brakes on a bike. On road bikes you would also have to consider that it's going to largely be the TIRE that is the weak spot in stopping rather than the brakes themselves, the limited contact patch of a skinny tire just can't exert enough friction to stop as well as a fat tire can. As far as being in it's infancy, I suppose so but if you get them and they work and you can get the parts when it comes to fixing them what difference does it make?

I would be more concerned about the fit of the bike and whether you just LIKE the thing enough to pull the trigger and buy it.

rdtompki

a) where do you ride?
b) how much do you weigh?

I wouldn't describe the technology as immature, but certainly on a different part of the maturation curve than rim brakes. Rotor technology is advancing to better control heat build-up (Avid HSX, Shimano ICE XT). While fork designs may not yet have been optimized, reputable manufacturers will add extra margin to safety critical components unless they are specifically design for high-end race applications.

I've found discs to be very easy to keep in adjustment and the difference in control and security on long descents is significant, but I weigh 200 lbs. The less the combined weight of rider and bike, the more braking will be limited by the tires. Many riders at my weight are comfortable with calipers on big descents (we're talking switchbacks of course) so YMMV.

I bought a first year Volagi with the 130mm rear hub spacing. In my mind this was the only quirk, similar to Santana's 160mm rear hub spacing. This isn't an issue other than smaller selection of hubs for a second wheelset. Current Volagi's have the more standard 135mm spacing.

Most of these threads have anecdotal and otherwise stories of difficulty adjusting disc brakes or even just getting the wheels back on, but I haven't found this to be the case at all. Why just the other day my son (37 y/o of above average intelligence I think) managed to put the front wheel of the Volagi on while I was changing into my cycling clothes. By way of comparison, I'd say there is more "art" to setting up FD and RD, maybe verging on black magic judging from posts on the subject.

merlinextraligh

The rider definitely contributed. My point though is that there is still a lot lef to dial in discs for road bikes, including the optimal sized rotors, pad comnbinations, wheel design.



I really question the need for discs on a road racing bike. But if the market is going to go there, there's a lot left to be done to optimize them. You're adding weight with the discs, but you may be able to take some of that back out such as with disc specific rims (i.e. no brake tracks).

So, my bet is that discbrakes on road bikes are going tobe a very small niche 3-5 years from now, or alternatively, they're going to take off and they're going to take off, and the total design, the brakes themselves, and the ancillary parts are going to be substantially better than Disc Brake Road Bike 1.1.

Hence the answer to the OP's point, now is not the time.

JCNeumann

Most high-performance motorcycles have triple discs - two front and one rear. If rotors or pads are not able to dissipate the heat load, you just make the rotor bigger or thicker and the pad surface larger. Plus, you design the disc surface to allow out-gassing from via slots or holes.

This will impact aerodynamics, and would probably require use of hydraulics.

The challenge with this is weight and rotational mass, as balanced against braking ability. In addition, how much contact surface between the tire and road can handle braking and turning? Some higher-end motorcycles have ABS to avoid skidding, and it changes the bikes handling significantly - I don't think that's an option for bicycles due to weight. (I had a 1992 BMW K75s with ABS and it added ~ 15 pounds on a 400 pound bike)

Dont know if this helps - just some information for motorcycles, which have some similar braking issues at high speed.

(I believe MotoGP bikes actually have carbon/ceramic discs and pads in dry conditions. Apparently they are much more resistant to fade)

Commodus

Many (all?) of the early failures an be attributed to the use (and abuse) of prototype, lightweight hydraulic systems.

I've been running BB7s on my touring bike for years. They're amazing. They've always been able to stop me and my gear coming down the various mountains I've ridden, and I've never had to replace the rims on that bike - no wear!

bikerjp

So no one ever rode a disc equipped cross bike on the road? I hope those bikes come with a warning about using your cross bike for non-cx riding. Could be ugly.

etw

The 2 top Secteur models use discs https://www.specialized.com/us/en/bikes/road/secteur