Disc Brakes on the Tours?

d4mi4nr

http://twitter.com/lancearmstrong/status/3212413403

Do you think anything will come from this?

redddraggon

Unlikely

whyamihere

Disc brakes are banned by the UCI.

Smokin Joe

whyamihere wrote:

Disc brakes are banned by the UCI.

Ah, those forward thinking people at the UCI, where would we be without them? (On faster bikes that are easier to ride, but lets not moan at least they let us get away from penny farthings).

I can see discs comming for road bikes, particularly if a few more high profile riders take up the cause. Having just junked an otherwise perfectly usable Vento wheel because the rim was worn out I would be all in favour.

shouldbeinbed

why not up the weight limit and add a trailer with a small passenger instead.

it'd make the sprints more like the Ben Hur chariot race

Garry H

whyamihere wrote:

Disc brakes are banned by the UCI.

Why is that?

redddraggon

Garry H wrote:

whyamihere wrote:

Disc brakes are banned by the UCI.

Why is that?

Eddy Merckx and co didn't use them

Sirius631

Garry H wrote:

whyamihere wrote:

Disc brakes are banned by the UCI.

Why is that?

Do you want all that stopping power in the middle of a slow reacting pack, especially amongst cat 4 amatuers?

Smokin Joe

Sirius631 wrote:

Garry H wrote:

whyamihere wrote:

Disc brakes are banned by the UCI.

Why is that?

Do you want all that stopping power in the middle of a slow reacting pack, especially amongst cat 4 amatuers?

Stopping power is governed by the grip from the tyres, and on a road bike that isn't much. The brake can be tuned to suit, it isn't like an on/off switch.

Sirius631

Smokin Joe wrote:

Sirius631 wrote:

Garry H wrote:

whyamihere wrote:

Disc brakes are banned by the UCI.

Why is that?

Do you want all that stopping power in the middle of a slow reacting pack, especially amongst cat 4 amatuers?

Stopping power is governed by the grip from the tyres, and on a road bike that isn't much. The brake can be tuned to suit, it isn't like an on/off switch.

It's bad enough when people grab a handful of brake lever when using caliper brakes. Don't want to be anywhere near anyone else when the concertina effect hits the back of a bunch if disc brakes were used. The effect will be uncontrolled front and rear wheel lock-ups and skids.

Smokin Joe

Sirius631 wrote:

Smokin Joe wrote:

Sirius631 wrote:

Garry H wrote:

whyamihere wrote:

Disc brakes are banned by the UCI.

Why is that?

Do you want all that stopping power in the middle of a slow reacting pack, especially amongst cat 4 amatuers?

Stopping power is governed by the grip from the tyres, and on a road bike that isn't much. The brake can be tuned to suit, it isn't like an on/off switch.

It's bad enough when people grab a handful of brake lever when using caliper brakes. Don't want to be anywhere near anyone else when the concertina effect hits the back of a bunch if disc brakes were used. The effect will be uncontrolled front and rear wheel lock-ups and skids.

The more stopping power a brake has the easier it is to regulate the braking effort and avoid lock-ups. The lighter touch required gives a greater degree of feedback. It is crappy brakes which have to be grabbed with a death grip which are prone to lock the wheel.

Garry H

Smokin Joe wrote:

The more stopping power a brake has the easier it is to regulate the braking effort and avoid lock-ups. The lighter touch required gives a greater degree of feedback. It is crappy brakes which have to be grabbed with a death grip which are prone to lock the wheel.

That's what I thought as well, hence the question.

Lynx_516

Smokin Joe wrote:

The more stopping power a brake has the easier it is to regulate the braking effort and avoid lock-ups. The lighter touch required gives a greater degree of feedback. It is crappy brakes which have to be grabbed with a death grip which are prone to lock the wheel.

Assuming that the retarding force a brake applies is linear or close to it is probably a fairly poor assumption. While the lighter touch does allow for a reduced neural noise,your it does assume that at low application forces the retarding force is still vaguely linear, when it probably would not be. Thus having stronger brakes may not necessarily be a good idea.

One argument I have heard against disks on road bikes is that in the event of a crash a disk can be a pretty nasty weapon. (Think of a 2mm disk coming at you at 30mph).

Smokin Joe

There must be carnage in motorcycle racing then, where the discs will be coming at you at 200mph. Oh wait a minute, the disc is inside the fork. How is it going to come hurtling at you like a heavyweight frisbee?

I know from experience of cars and motorcycles that the weakest brakes result in the most lock-ups, because you have to use so much effort that your sense of touch has gone. In any case, as I've already said the performance of the disc can be tuned at manufacture by the rate of cable pull and the size of disc and pad.

andrewjoseph

Lynx_516 wrote:

Smokin Joe wrote:

....

One argument I have heard against disks on road bikes is that in the event of a crash a disk can be a pretty nasty weapon. (Think of a 2mm disk coming at you at 30mph).

Not half as nasty as chainrings! usually the tyre/rim will hit you before the rotor and it will depend on which side the bike is falling. i.e. left or right side will mean rotor is above horizontal wheel or below it.

A chainring can cut you to pieces no matter what side the bike falls.

I'm having disks put on our tourers.

rake

youl have more inertia in the wheel with a disc. not good for acclelerating. what about the load on the spokes and rim when you break. the wheel would have to be much heavier to not rip the spokes out which would have a higher breakage rate. no more radial lacing could be used and would give more lateral movement. the forks would have much more leverage load on them because the smaller diameter brake would have to have a greater force for the same stopping power and the load will be at the thin end of the fork, not a good idea if you want light weight carbon forks. not even mentioning the wider clearance needed to fit the disc between the fork and spokes. it a craap idea. stick to riding hes no mechanic.
like when chavs put bigger wheels on a car and wonder why the brakes dont work as well with less leverage.

whyamihere

rake wrote:

youl have more inertia in the wheel with a disc. not good for acclelerating. what about the load on the spokes and rim when you break. the wheel would have to be much heavier to not rip the spokes out which would have a higher breakage rate. no more radial lacing could be used and would give more lateral movement. the forks would have much more leverage load on them because the smaller diameter brake would have to have a greater force for the same stopping power and the load will be at the thin end of the fork, not a good idea if you want light weight carbon forks. not even mentioning the wider clearance needed to fit the disc between the fork and spokes. it a craap idea. stick to riding hes no mechanic.

Same things were said about mountain bikes. Now you won't see a decent bike without them, even most of the super weight weenie bikes.

If they were allowed, we'd be using discs. Some CX bike have started getting discs even though they're not allowed in competition.

rake

mountain bikes have smaller wheels with higher spoke counts. suspension forks are heavier and stronger anyway. its totally different on mountainbikes. the main reason was to avoid the jamming up with mud problem, if that happens on your road bike you need a garmin 705. :roll:

Buckled_Rims

The interesting thing is hydraulic disc brakes could easily be rigged up to an anti-locking system. As computers on the bikes measure all sorts now, surely it's not hard to tie in mph with wheel revs times applied lever pressure...or something like that. Even the Shimano electonic gear changing set could be used.

Hey what fun it'll be to have traction control switched on

rake

have you looked at a car abs compressor. thats some pipework and big block of metal on the bike.i think were soving a problem that doesnt exist here. then what would they charge if they pulled it off. what if it malfunctioned.

crimsondynamo

A chum of mine has the Boardman road bike with flat bars and discs (and a heavy duty cf fork) for commuting. The safety advantages are clear. To suggest discs are unsafe on road bikes is a bit odd.

@Rake - I think you're missing the point. No one is disputing that discs mean a heavier set up, but the pro bikes have plenty weight to spare to make UCI minimum, that's why LA was suggesting it.

Smokin Joe

rake wrote:

have you looked at a car abs compressor. thats some pipework and big block of metal on the bike.i think were soving a problem that doesnt exist here. then what would they charge if they pulled it off. what if it malfunctioned.

Who said disc brakes have to be hydraulic? The first motorcycle I ever had with a disc brake was cable operated. It isn't a question of solving a problem that doesn't exist, it's about imprving the existing system, rather like STI/Ergo shifters improved gearchanging.

I seem to remember all the same school of objections when they first appeared, now most riders would not look at a bike without them.

desweller

Discs would be great. Brakes that actually work! Rims that don't get eaten by the winter crap! None of that poxy fiddling about with the pads to get them to land on the rim correctly!

Bring it on.

Fridge-Seal

rake wrote:

mountain bikes have smaller wheels with higher spoke counts. suspension forks are heavier and stronger anyway...

Ahh yes, but what about 29" wheels on MTB's? (correct me if I'm wrong) but most Road wheels are 27 inches are they not?

29'ers seem to cope fine with the loading provided by disc brakes, plus, they are usually subjected to a harder time than most road wheels.

ABS system would be total overkill.

rake wrote:

youl have more inertia in the wheel with a disc. not good for acclelerating...

you can get really light discs (Ashima/Jetblack Air-rotor, any other rotor on high end brakes)

Shouldn't really be a problem, would be interesting to see it take off.

Smokin Joe

You would also save weight on the rim, probably the place where it matters most. Rims could be manufactured to minimum safe wall thickness and not have to have three or more years worth of brake wear built in.

Monty Dog

I have a cross bike with discs and fitted with lightweightroad tyres, braking performance is awesome - way better than any caliper brake because of where the brake force is applied plus the level of control - you can brake mid-turn with a disc, something not adviseable with a caliper because of the force it exerts on the rim. If someone like Avid were to make the BB7 with magnesium and composites and a 150mm rotor it would easily keep the bike within the UCI limits. Yes there's the risk of being cut by a disc in a crash, but the fact that better braking control might actually reduce the number of crashes?

rake

Smokin Joe wrote:

rake wrote:

have you looked at a car abs compressor. thats some pipework and big block of metal on the bike.i think were soving a problem that doesnt exist here. then what would they charge if they pulled it off. what if it malfunctioned.

Who said disc brakes have to be hydraulic? The first motorcycle I ever had with a disc brake was cable operated. It isn't a question of solving a problem that doesn't exist, it's about imprving the existing system, rather like STI/Ergo shifters improved gearchanging.

I seem to remember all the same school of objections when they first appeared, now most riders would not look at a bike without them.

i dont doubt it i ride a mountain bike with cable operated disc.
i was replying to the idea of abs on a bike. ive never seen cable operated abs.
in any case i just dont want to see disc brakes on a road bike. fine for off road or hybrid.
i have enough braking effect to lock wheels and dont have trouble going round corners.

Buckled_Rims

All it is is a braking system for christ's sake. What's wrong with that? They both in the mechanical form do exactly the the same thing...ie, squeeze pressure to a surface, either a rim or disc.

It will come eventually, so it's fairly pointless arguing over discs

rake

i dont think it will.

edhornby

a bonus for discs is that you won't get tyre blowouts from rims overheating the tyres

Ash_

edhornby wrote:

a bonus for discs is that you won't get tyre blowouts from rims overheating the tyres

And similarly, the heat won't melt the glue on sprint rims meaning your tubs shouldn't roll off. Not a big deal in the UK, but on long Alpine descents it might make the difference, especially for 'chunkier' riders.

In fact, Indurain already tried using a front disc about fifteen years ago - made by Hope - I think he rode it in the Dauphine Libere (either 94 or 95 I'm not too sure). He also used a triple chainset for the stage to Grenoble...

So Lance is well behind on this one.