Disc brakes on road bikes.....
Disc brakes on road bikes.....
Author
Discussion

E65Ross

Original Poster:

36,729 posts

241 months

Sunday 17th May 2015
quotequote all
I can see the benefit....road bike brakes are typically pretty rubbish but they aren't THAT bad, but do the modern, expensive bikes with discs (road bikes costing north of £5k) weigh considerably more than their counterparts with a traditional brake set?

You never see a TdF rider with discs....

Many thanks

Jimbo.

4,216 posts

218 months

Sunday 17th May 2015
quotequote all
E65Ross said:
I can see the benefit....road bike brakes are typically pretty rubbish but they aren't THAT bad, but do the modern, expensive bikes with discs (road bikes costing north of £5k) weigh considerably more than their counterparts with a traditional brake set?

You never see a TdF rider with discs....

Many thanks
You don't see them in the TdF because they're not permitted.

There's not much of a weight difference IIRC: beefier forks and stays and the discs, but lighter rims (no braking surface necessary).

Rim brakes are fine in the dry: good cables, pads and clean rims will stand the bike on its front wheel (quite good fun actually biggrin). It's in the wet where discs have the advantage, although any extra power has to be used with care, as the wet roads will increase the risk of locking the front.

I'm not sold, personally: standards are still up in the air re. axles, hub widths, disc fixings etc, etc: they'll need a couple more years to mature in that respect.

Edited by Jimbo. on Sunday 17th May 17:19

Magic919

14,485 posts

230 months

Sunday 17th May 2015
quotequote all
Teams start testing them in races from August.

Alicat

249 posts

259 months

Sunday 17th May 2015
quotequote all
Well, I have made the change and what a difference, I won't go back. They are definitely sharper, more reliable and the modulation is better, you can feel the braking force. As for the weight, well no difference on my bike.

E65Ross

Original Poster:

36,729 posts

241 months

Sunday 17th May 2015
quotequote all
Interesting....

Alicat - surely they weigh more than if that same bike had a traditional caliper set up?

Jimbo.

4,216 posts

218 months

Sunday 17th May 2015
quotequote all
E65Ross said:
Interesting....

Alicat - surely they weigh more than if that same bike had a traditional caliper set up?
Rim-brake wheels need a bit of extra meat on the rim to allow for wear and, I imagine, braking forces of one form or t' other.
You've the dis) caliper, but you're losing the rim caliper (which are quite chunky themselves).
You've the disc brake mounts, but you're losing the rim brake mounts.

gazza285

11,134 posts

237 months

Sunday 17th May 2015
quotequote all
Hydraulic disc brakes, yes. I know personally of a few people who have come unstuck with cable disc brakes wearing the pad enough on one ride to render the brakes useless, one of whom ended up with a broken neck. This was a slightly on and off road ride of thirty miles in the rain, the muck and water ground the pads down until the lever came back to the bars.

E65Ross

Original Poster:

36,729 posts

241 months

Sunday 17th May 2015
quotequote all
Jimbo. said:
E65Ross said:
Interesting....

Alicat - surely they weigh more than if that same bike had a traditional caliper set up?
Rim-brake wheels need a bit of extra meat on the rim to allow for wear and, I imagine, braking forces of one form or t' other.
You've the dis) caliper, but you're losing the rim caliper (which are quite chunky themselves).
You've the disc brake mounts, but you're losing the rim brake mounts.
But do the forks, stem, headset etc not need to be beefed up to cope with extra forces?

I'm not going against discs at all, far from it... Just trying to see whether they'd be worth it on my next roadie!

Alicat

249 posts

259 months

Sunday 17th May 2015
quotequote all
My advice, try a bike with disks and see what you think!


graeme4130

3,955 posts

210 months

Sunday 17th May 2015
quotequote all
The TDF guys are being allowed by the UCI to race them next year
However, they're yet to come up with a solution to the speed of wheel changes a traditional calliper braked bike offers, and if you've seen how quick they change a wheel on the roadside in the pro tours, you'll understand as disc brakes require a lot more alignment to get the wheel in
Also, from my point, you have a lot of force going through the spokes on a disc wheel under heavy braking, so the wheels have to have slightly thicker spokes, which negates a lot of the rim saving
That said, they offer way better braking performance, especially on a carbon rimmed wheel in the wet, which is rubbish at best and dangerous some of the time even with modern brake block technology (anyone remember the original cork blocks that provided no braking in the wet at all until they'd done a couple of wheel rotations, and then just locked up?)

Jimbo.

4,216 posts

218 months

Sunday 17th May 2015
quotequote all
graeme4130 said:
The TDF guys are being allowed by the UCI to race them next year
However, they're yet to come up with a solution to the speed of wheel changes a traditional calliper braked bike offers, and if you've seen how quick they change a wheel on the roadside in the pro tours, you'll understand as disc brakes require a lot more alignment to get the wheel in
Also, from my point, you have a lot of force going through the spokes on a disc wheel under heavy braking, so the wheels have to have slightly thicker spokes, which negates a lot of the rim saving
That said, they offer way better braking performance, especially on a carbon rimmed wheel in the wet, which is rubbish at best and dangerous some of the time even with modern brake block technology (anyone remember the original cork blocks that provided no braking in the wet at all until they'd done a couple of wheel rotations, and then just locked up?)
Thicker spokes aren't as necessary as appropriate lacing. Straight-pull on discs is an no-no!

Hobzy

1,271 posts

240 months

Sunday 17th May 2015
quotequote all
gazza285 said:
Hydraulic disc brakes, yes. I know personally of a few people who have come unstuck with cable disc brakes wearing the pad enough on one ride to render the brakes useless, one of whom ended up with a broken neck. This was a slightly on and off road ride of thirty miles in the rain, the muck and water ground the pads down until the lever came back to the bars.
Surprised at that - the pads on my MTBs last a few hundred miles even in the winter riding Swinley! Surely the pads aren't that different compound wise?

Justin S

3,658 posts

290 months

Sunday 17th May 2015
quotequote all
Standard organic resin pads are great in the dry, which is what is specced on new brakes from the factory, but in the wet can dissolve quite quickly. Other issues with mechanical disc brakes, is that if the pad wears, the inside pad will need to be manually adjusted, so more a user error than a brake fault. Hydraulics will self adjust the pads like your car, but for riding in heavy rain, then sintered pads are where you will need to go, to last the ride, in the same way us seasoned mountain bikers have ridden for many years with disc brakes.
If I was to start again with my road bike, then I would go discs, without a second thought. I've tried everything with my rim brakes on both my road bikes and they wont slow you down like discs and with discs, your rims will never wear out.

E65Ross

Original Poster:

36,729 posts

241 months

Sunday 17th May 2015
quotequote all
Just had a look regards to weight. Mavic ksyrium pro disc wheels vs they're ksyrium SL wheels.... The non disc wheels are a little cheaper but, as a pair, weigh approx 700g less. That's quite a lot of rotating mass!

marmitemania

1,571 posts

171 months

Sunday 17th May 2015
quotequote all
Can't see the point of them on road bikes. If you are a good rider and know the bike you ride within its limits. I have a Marin MTB with Hope hydraulic discs on it and it's fantastic but it needs to be on an MTB. If your riding in a peleton with discs they present a real danger to you and others not just if you come off and a red hot disc slices through you, but also if you can stop a lot quicker and in shorter distance than the non disc chap behind you in the peleton then...... I think you see my point but then what do I know it's just my opinion. I personally think it's just another gimick as we are getting close to melting point with road bike development and now need to look for some new things ala discs on road bikes.

Get Karter

1,950 posts

230 months

Sunday 17th May 2015
quotequote all
marmitemania said:
Can't see the point of them on road bikes...... I personally think it's just another gimick as we are getting close to melting point with road bike development and now need to look for some new things ala discs on road bikes.
Spot on, imho.

marmitemania

1,571 posts

171 months

Sunday 17th May 2015
quotequote all
Get Karter said:
marmitemania said:
Can't see the point of them on road bikes...... I personally think it's just another gimick as we are getting close to melting point with road bike development and now need to look for some new things ala discs on road bikes.
Spot on, imho.
Thank you kind Sir.

BadgerBenji

3,534 posts

247 months

Sunday 17th May 2015
quotequote all
Justin S said:
Other issues with mechanical disc brakes, is that if the pad wears, the inside pad will need to be manually adjusted, so more a user error than a brake fault
You might want to take a look at TRP Spyres, they actuate both pads with one single arm.

marmitemania

1,571 posts

171 months

Sunday 17th May 2015
quotequote all
Just a footnote to my earlier comment. I ride at club level and we ride fast and very close when working right. I would not dream of turning up with discs for a group ride.

BadgerBenji

3,534 posts

247 months

Monday 18th May 2015
quotequote all
marmitemania said:
Just a footnote to my earlier comment. I ride at club level and we ride fast and very close when working right. I would not dream of turning up with discs for a group ride.
It's no different to using conventional brakes, you apply the lever until the correct amount of braking is happening. You do realise brakes are not a switch you can apply them gently or hard, or even heres the concept anywhere in between.