/ disks on a road bike?

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mark s - on 31 Dec 2012
will this become more popular?
i have noticed at times when out in the damp how crap rim brakes really are.especially with being a bit heavier than the average road cyclist.
im sure a smaller version of mtb brakes so delivering less torque would be ok on those skinny tyres.
ive never done any of the bike alpine descents but im 100 % sure in those situations disks would eliminate the fear of over heating the rims.
plus they look good
mark s - on 31 Dec 2012
In reply to mark s: was meant to say 'big alpine descents' dont know why i typed that.
Bean Head - on 31 Dec 2012
In reply to mark s:

I think it's going to happen. I've got them on my tourer and whilst being underwhelmed at first, I've come to appreciate they're not about ultimate stopping power but modulation, control and consistency in all conditions. I definitely prefer them.

They do seem to need constant attention and are sensitive to being knocked about; sometimes replacing the wheels can lead to disc rub, though others don't agree with this. And I think they look ugly on road bikes.

I think it'll be a while before we see them in the pro peloton and until then I think manufacturers will be unwilling to commit wholeheartedly.

Rob
sleavesley on 31 Dec 2012
In reply to mark s: You mean like this? http://www.colnago.com/c59-disc/
mark s - on 31 Dec 2012
In reply to sleavesley: ooh nice
KellyKettle - on 31 Dec 2012
In reply to mark s: They're not UCI sanctioned, so they're unlikely to start appearing on true race bikes until that changes... They have begun to make an impression on Cyclocross though, where moisture and dirt are a real issue.

If I had the cash to replace my forks and have tabs welded to my frame, I'd have a set on my bike tomorrow; it feels like a massive step backwards in terms of breaking 'feel' going from disks on the MTB to cantilevers on the CX bike.
sleavesley on 31 Dec 2012
In reply to mark s: Yeah nice price too - 10,000 or 3800 just for the frame! It is their high end bike though.
andy - on 31 Dec 2012
In reply to mark s: I've got them on my winter bike - it's a CX frame with Avid BB7 road disc brakes. I prefer it to the frequent "oh shit!" moments of rim brakes in the wet.
Jamming Dodger on 31 Dec 2012
In reply to andy: As opposed to these "oh shit" moments?
http://www.bikerumor.com/2012/02/14/road-bike-disc-brakes-are-coming-but-will-they-work/
Think it's to do with the speeds road bikes get to and the forces they have to overcome.
But I have them on my 700c commuter. The cables need changing regularly or they just snap.
Shearwater - on 31 Dec 2012
In reply to mark s:
> im 100 % sure in those situations disks would eliminate the fear of over heating the rims.

...and replace it with the fear of cooking the discs or boiling your brake fluid ;-)

I've got avid bb7 road cable disc brakes on one of my bikes. They've been entirely satisfactory, and I've felt no need to investigate the various ways hydraulic brakes can be made to work with drop handlebars.
johnj on 31 Dec 2012 - 86.112.78.158 whois?
In reply to sleavesley:
> (In reply to mark s) You mean like this? http://www.colnago.com/c59-disc/

That's proper sexy, awwww man I need a woman in me life, getting turned on by push bikes, whats next mudgaurd porn?
Alun - on 31 Dec 2012
In reply to Shearwater: & Jamming Dodger

Cable disc brakes are a marketing ploy to make cheap bike look more expensive. As you say, they are satisfactory, but offer no real improvement over a decent set of cantis (or Vs on an mtb).

Hydraulic discs, on the other hand, are a different kettle of fish. As somebody else said above, it's not about the extra power (in the dry, a lightweight disc is not much better than decent rim brakes), it's about the consistency of braking in all conditions, and especially on long descents.

On the other hand, for the industry they are yet another luxury item to sell to overpaid middle-aged with money to burn on bikes and parts they don't need.

For both of the above reasons, I am pretty confident that they will appear more and more on road bikes in the future, and eventually become standard, much like they have done on mountain bikes.
Jamming Dodger on 31 Dec 2012
In reply to Alun: Not totally sure i agree with that first point. I got a commuter with disc brakes cause the stopping power in the wet is infintely better than any cantis of v brakes ive ever had. They just need maintaining more regularly. However on a road ride id be more worried about the disks being cooked on a fast descent than the cables pinging. Feathering the brakes on a sketchy descent would be a nightmare waiting to happen.
On cross bikes though I think theyd be the bomb. I have decent cantis on my crosser and they are great in the dry, totally rubbish in the wet. And the road brakes on the road bike are just shocking in wet weather.

johnj on 31 Dec 2012 - 86.112.78.158 whois?
In reply to Jamming Dodger:

Hello, the only reason for 'cooking' a set of discs on a pretty light bike going not really that fast 65 max is having the wrong pads fitted, or possibly in the rare case of discs been undersized. Same with boiling brake fluid generally just down to underspec of dot or badly bleed with little pin size air bubbles which when hot can expand to the size of the master cylinder, same goes with old (anything of more than 6 month with really heavy use) fluid as dot fluid is hygroscopic in nature the fluid becomes contaminated. Then we expect folk on minimum wage shop work to service these pretty hi-tech machines to the correct levels often that doesn't happen.

As a side point road rim brakes if shimano generally have brake blocks fitted which are pretty wooden last a long time mind. Lots of good brake blocks on the market to improve the feel.
Jamming Dodger on 31 Dec 2012
In reply to johnj: Ill have to bow down to your superior knowledge on this one ;)
Setting up brakes is not my forte!
johnj on 31 Dec 2012 - 86.112.78.158 whois?
In reply to Jamming Dodger:

Hey, thanks for your kind words:)

What you've got to remember we've spend years in sheds, garages, shops, back gardens, and at the side of the road or track sorting out these kind of issues, sometimes you've got to do something a lot of times to get the hang of it. However I think it's good to share the knowledge base of what one has learnt whenever possible.
onefootholdinthegrave - on 31 Dec 2012
In reply to mark s: Get a cyclox bike that will take thicker tyres. If still not satisfied fit avid bb7 (60 per end). look at Cotic X and Genesis Croix de Fer as examples of good value bikes designed for UK use on rough/wet roads and not too technical off road.
Camm on 31 Dec 2012
In reply to mark s:
I've got discs on my hybrid, wouldn't have anything else, cable brakes (disc and rim) have let me down but haven't got anything bad to say about discs, the only other thing I'd have is hydro rim brakes.

As for stopping power, if you can lock the wheels up then you have enough ;)

Though discs give you much more control.
gethin_allen on 31 Dec 2012
In reply to mark s:
I always see the crap brakes on my road bike as a device to stop me being silly and coming off in a skid. If the brakes can't cope the tyres probably can't.
Another issue with disk brakes on roadies I can see is the uneven torsion stresses on forks and frames meaning that you need heavier frames and forks.
Talius Brute - on 31 Dec 2012
In reply to sleavesley:
> (In reply to mark s) You mean like this? http://www.colnago.com/c59-disc/

That is properly gorgeous.
johnj on 31 Dec 2012 - 86.112.78.158 whois?
In reply to gethin_allen:

Indeed the frame design needs looking at but what you add somewhere you take away from someplace else braking forces are generated anyway, you're just altering layout, would all be part of design intent.
gethin_allen on 31 Dec 2012
In reply to johnj:
Currently though, brake forces are focused on the crown or the top of the seat stays(classic strong regions) and distributed evenly to each fork leg or stay.
There may even be issues with wheel and axle/hub strength.
johnj on 31 Dec 2012 - 86.112.78.158 whois?
In reply to gethin_allen:

Yeah no doubt probably many bike companies use standard parts to assemble, with no real finite element design analysis, or detailed prototype or destructive testing, and as they have good insurance polices, they use these industry standard parts to assemble by the lowest bidder for the highest mark-up and us the end user does the real road testing, and as with any new release to the market there are failures.
Bean Head - on 31 Dec 2012
In reply to gethin_allen:

With the UCI minimum weight limit still at 6.8kg and people building ridable sub 5kg (even sub 4kg) bikes, I don't think building in extra strength is a concern.

Rob
fraserbarrett - on 01 Jan 2013
In reply to mark s: unlikely to get into racing in my opinion, even if the rule change. The current setup can easily lock the wheels, and heat dissipation from the rims is much better than discs, and there is less issue with distortion/ mud which was the real motivation on mountain bike.
Btw the forces are less on rim braking due to the mechanical advantage of being several times further from the hub.
RankAmateur on 02 Jan 2013
In reply to mark s:
I'm a 15st fatty, so I'm more than happy to have cable disk brakes on my hybrid. I no longer have anywhere near as much fear in the wet.
existing debt - on 02 Jan 2013
In reply to mark s:

I always view the brakes on my roady as a means to slow me down rather than stopping. last thing you want to do is grab a handfull off brake on skinny tyres....I run two mountain bikes both with disk brakes and i am forever messing around with them, trying to get the feel right. im quite happy with the slowing/stopping power of my normal roady brakes and definitely happy with the maintenance side of things.

Hephaestus - on 02 Jan 2013
In reply to mark s:
> will this become more popular?

One massive issue for me is cost. If using a bike every day, the wear and tear costs on disc brakes would quickly build up in addition to the initial outlay.

As noted above, one of the main advantages of disc brakes on mtb's is that the mud and grit isn't mashed into the wheel rims every time you brake. That meant a reduction in overall cost, because the wheels lasted much longer.
EeeByGum - on 02 Jan 2013
In reply to Hephaestus: Agreed - as things are I have to service my brakes at least every two weeks. I am not sure if I could cope with expensive and fiddly disk equivalents. I have also found that if you buy decent brake blocks, stopping in the wet isn't such an issue.
Alun - on 02 Jan 2013
In reply to johnj:
> Then we expect folk on minimum wage shop work to service these pretty hi-tech machines to the correct levels often that doesn't happen.

You raise an interesting point about maintenance - although things are getting better. I have a 10-year-old Hope M4 which, after a couple of seal changes to both caliper and lever, is still going strong - but I've spent ages looking after it. Compare and contrast with a modern XT which is more powerful and much easier to set up, but is now on it's second (very expensive) caliper unit because you can't take them apart when the seals go. Much like modern cars and their fancy electronics - the price you pay for all that convenience is the inability to fix it yourself!

This said, that drive towards convenience is what makes me think that discs will be on most road bikes within a few years. XT mtb discs are childs-play to install - way easier than any caliper brake. So I reckon they'll be coming soon.

BTW some of you lot are moaning about having to service your brakes every few weeks... I haven't looked at my road bike's brakes for the last 1000km. Although it hasn't rained here for nearly two months...! (hee hee! sorry...)
Timmd on 05 Jan 2013
In reply to Jamming Dodger:
> (In reply to andy) As opposed to these "oh shit" moments?
> http://www.bikerumor.com/2012/02/14/road-bike-disc-brakes-are-coming-but-will-they-work/
> Think it's to do with the speeds road bikes get to and the forces they have to overcome.
> But I have them on my 700c commuter. The cables need changing regularly or they just snap.

Do you have cheapish Shimano cable discs and have the cables snap at the disc-brake end of the cable by any chance?

I noticed a fraying brake cable just at or near the 'pivot point' on a front cable disc a while ago, and wondered if it was specific to that kind of cable disc or to all cable discs.

Not wanting to muddy Shimano's name in an unwarranted way at all it should be noted...
Timmd on 05 Jan 2013
In reply to Jamming Dodger:
> (In reply to Alun) Not totally sure i agree with that first point. I got a commuter with disc brakes cause the stopping power in the wet is infintely better than any cantis of v brakes ive ever had. They just need maintaining more regularly. However on a road ride id be more worried about the disks being cooked on a fast descent than the cables pinging. Feathering the brakes on a sketchy descent would be a nightmare waiting to happen.
> On cross bikes though I think theyd be the bomb. I have decent cantis on my crosser and they are great in the dry, totally rubbish in the wet. And the road brakes on the road bike are just shocking in wet weather.

Current best practice on road bikes going down alpine descents on road bikes is to not feather tha brakes, but to brake before the corners before letting go and then braking before the corners again, kind of 'on' then 'off' to avoid the rims overheating and having a blow out.

I guess that could be the solution for now, untill things develop a bit more with road discs on road bikes.
Jamming Dodger on 05 Jan 2013
In reply to Jamming Dodger: In reply to Timmd: I'm far too much of a chicken to ride like that!
In response to other post, yep they are bog standard shimanos. I was dead set on disks for my commuter and they are brilliant in the wet but the cables do have a tendency to snap exactly as you describe. I wondered if it was just how they were set up or cause they're on 700 wheels and are used at speed. Meh... At least cables are cheap to replace!
Timmd on 05 Jan 2013
In reply to gethin_allen:
> (In reply to johnj)
> Currently though, brake forces are focused on the crown or the top of the seat stays(classic strong regions) and distributed evenly to each fork leg or stay.
> There may even be issues with wheel and axle/hub strength.

http://www.en.tout-terrain.de/accessories/forks/

Asymetric forks here...

If you transfer the technology from mtbs the problems with wheel and hub strength are sorted out i'd have thought?

Fulcrum the company owned by/partner of Campagnolo make disc mtb wheels with interesting spoke and rim designs, I think it wouldn't take a lot of work for them to design safe road wheels after what they've learnt making mtb wheels, and 'cross wheels soon I guess.
Timmd on 05 Jan 2013
In reply to Jamming Dodger:

At least they gradually fray (i'm guessing)?

Might be worth getting hold of some used road BB7s on ebay or singletrackworld and seeing if they have the same problem? It's not something i've noticed on my MTB BB7s, i've only got through one set of pads so far to be fair, though.

Might have an ask on singletrackworld.com about road BB7s, have been vaguely planning a disc road bike build for when I have the funds.



Timmd on 05 Jan 2013
In reply to Jamming Dodger:
> (In reply to Jamming Dodger) In reply to Timmd: I'm far too much of a chicken to ride like that!
> In response to other post, yep they are bog standard shimanos. I was dead set on disks for my commuter and they are brilliant in the wet but the cables do have a tendency to snap exactly as you describe. I wondered if it was just how they were set up or cause they're on 700 wheels and are used at speed. Meh... At least cables are cheap to replace!

Aha! Thought they might be. It could be down to the bend which the cable goes through is what I was thinking when looking at one, because the cable seemed to be fraying around the bend, which is what you'd expect to happen I think, from what little i've absorbed to do with metal fatigue.

Definately going to investigate road BB7s...
Jamming Dodger on 05 Jan 2013
In reply to Timmd: Its not that gradual at all I've found. After the first time I kept a close eye and theres not a big gap between frayed a little and frayed a lot. But then the bike does a lot of miles with a lot of stop-starting. I'm not bothered about changing the brakes at moment. I can live with changing the cables every few weeks. Costs 2 a time. Only my work bike that I'd not be caught dead riding on a club run so I can put up with it. Do ask around though and keep us posted with any interesting news.
Timmd on 05 Jan 2013
In reply to Jamming Dodger:Will do.
Timmd on 06 Jan 2013
In reply to Jamming Dodger:Havn't come across anything to do with cables fraying on Avid BB7 road brakes, have seen a few accounts of using them for 6 or 7 years and not having to replace cables due to wear and tear.

I think you can be confident you'd not have to replace cables with BB7s. (:-))
gethin_allen on 06 Jan 2013
In reply to Timmd:
My issue wasn't really questioning the viability of them for working or safety it was more questioning if they would be as light as rim brakes after strengthening all the components required to make them safe.

Mtbs have been Doug disks for decades but they are total porkers compared to road bikes.
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Mikkel - on 06 Jan 2013
In reply to gethin_allen:

How much do a road bike weight these days?
I got a mtb weighing in at just under 10kg, which is build with no consideration to weight of components.

You really have to be a weight fanatic to think the weight would be an issue.

But then when i see the amount of trouble i see people go through to get a carabiner that weighs a few grams less than what they currently got i guess it is a valid point :0)

Build a commuter on a cross frame and running 29r wheels and Shimano Hydraulic brakes on it.
It will be flat bars until they bring out some hydraulic levers for drop bars.
Dave Kerr - on 06 Jan 2013
In reply to mark s:

Has anyone mentioned the fact that your rims should last much longer? Although it's not so much of an issue with road bikes as MTBs.
andy - on 06 Jan 2013
In reply to Mikkel:
> (In reply to gethin_allen)
>
> How much do a road bike weight these days?
>

8.5kg or less. My best bike claims 6.8kg but I think it's a couple of hundred grammes more - light bikes are psychological - even though I'm enormously fat I definitely find hills easier when I go off my heavier winter bike (mudguards etc) and onto my summer bike in April.

Far cheaper to eat less pies (which I also try to do).
andy - on 06 Jan 2013
In reply to gethin_allen:
> (In reply to Timmd)
> My issue wasn't really questioning the viability of them for working or safety it was more questioning if they would be as light as rim brakes after strengthening all the components required to make them safe.
>
> Mtbs have been Doug disks for decades but they are total porkers compared to road bikes.

They are definitely heavier - I have Avid BB7s on my winter bike, and they're roughly twice the weight of a set of Ultegra brakes. But where discs will make a difference is in having super-light rims as this is where you feel the difference on lightweight wheels.
Timmd on 06 Jan 2013
In reply to gethin_allen:
> (In reply to Timmd)
> My issue wasn't really questioning the viability of them for working or safety it was more questioning if they would be as light as rim brakes after strengthening all the components required to make them safe.
>
> Mtbs have been Doug disks for decades but they are total porkers compared to road bikes.

Right I see. With how enthusiastic the crew at Cycling Plus get at how quickly some wheels get upto speed, I think disc brakes on road bikes might lead to some great hill climbing wheels and lighter rims, much like andy does.

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