Disc Brakes on the Tours?

Fridge-Seal

Why are people concerned about rotors coming off in a crash?

Look at your average 6-bolt, IS standard rotor on an MTB, there's 6 bolt's in there, and they aren't weak ones!

You are highly unlikely ( I won't say impossible, because anything can happen :P ) to have a crash, in which rotors become flying blades of death


As for how it would operate, as far as I know, hydraulic systems are lighter than cable ones, hence why high end brakes from the likes of Formula, Shimano, Avid, Hayes and Hope all use hydraulics.

Buckled_Rims

Fridge-Seal wrote:

Why are people concerned about rotors coming off in a crash?

Look at your average 6-bolt, IS standard rotor on an MTB, there's 6 bolt's in there, and they aren't weak ones!

You are highly unlikely ( I won't say impossible, because anything can happen :P ) to have a crash, in which rotors become flying blades of death


As for how it would operate, as far as I know, hydraulic systems are lighter than cable ones, hence why high end brakes from the likes of Formula, Shimano, Avid, Hayes and Hope all use hydraulics.

It's not the discs coming off that's the worry. That's highly unlikely with either centrelock or bolts.

It's the bacon slicer effect that everyone's mentioning. If a bike crashes and is sliding, the disc could (in theory) become a sort of martial arts weapon of mass destruction, slicing peoples legs off, while still attached to the wheel.

It's strange how the brakes on a race bike is essentially stuck in past times, while everything else is racing ahead!

d4mi4nr

They seem to cope with disc brakes ok when crashing a gp bike. Dont think Ive seen any limbs lopped off?

redddraggon

redddraggon wrote:

Garry H wrote:

whyamihere wrote:

Disc brakes are banned by the UCI.

Why is that?

Eddy Merckx and co didn't use them

This is largely the reason.

The only reason MTBing gets away with all this new technology because it's a rather new sport and doesn't really have the same sort of history.

bompington

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?

Good idea, in fact if we follow that logic we should ban brakes altogether

Steve_b77

Isn't this somethign to do with bikes getting lighter and finding alternative ways to ensure that the bikes meet the minimum weight for tours etc?

Replacing disc brake pads is alot cheaper than rims.

Why would you end up ripping spokes out of the rim if the disc is mounted on the hub on a separate carrier to which the spoke do not come in contact with?

The increased inertia would be minimal as the disc is at the centre of the wheel and as a 160mm would weigh in the region of 100grams the increased rotational mass wouldn't be that much especially as it's acting no more than 80mm from the wheel axel - how much heavier is a powertap hub than a normal one?

If as a rider you keep unintetionally locking up brakes be they disc or rim then I'm affriad you're a bit of a numpty and should learn how to brake correctly before you even contemplate entering a race.

Fork clearance can be addressed by the dish profile of the wheel.

MrHulot

Whether discs will be allowed I don't know - arguements for and against. Either way, having seem a mate of mine in the club turn up on the Sunday run with an Orbea Diem Drop as his Winter/training bike the idea seems sound for us mortals.

Bugly

The issue with disk brakes on road bikes as I see it
1) the forces will be applied at the hub thus the spokes would need to be beefed up making the wheels heavier

2) as with the wheels the wheel stays and the fork will need a larger section or heavier guage for said forces

3) modern dual pivot brakes offer enough stopping power for use in a race

so adding the required weight increase (let alone sanction by UCI) would not provide direct benefit - nobody would want it.

For commuting on a bike I pay for however the reduced wear on the rims by using hydraulics may outway the extra cost and weight.

alfablue

Bugly, re: above I would say:

1) for any given braking force there is no difference between rim or disc brakes - the forces are between rims, spokes and hubs, just the same, wherever the force originates from.

2) I don't think so - I can already stop at eye-popping deceleration levels with rim brakes.

3) I think I agree, few would want it for racing, especially given 2) above

Finally, yes, I think I would still like them for commuting, but then again, I think my rim brakes do all I want, and a rim every 3 years is not so bad as I would probably replace the whole wheel if I had done high mileabes (plus, disc pads are generally more fiddly and costly).

Bugly

alfablue wrote:

Bugly, re: above I would say:

1) for any given braking force there is no difference between rim or disc brakes - the forces are between rims, spokes and hubs, just the same, wherever the force originates from.

Yep you are correct however if a greater force is applied by the disk brake you would need beefier hub flanges and spoke count/weight. I was considering that DISC brake has greater force avaliable then caliper
2) I don't think so - I can already stop at eye-popping deceleration levels with rim brakes.

yes I agree the current technology is more then sufficient but again if we increase the braking we need to beef up the bike
3) I think I agree, few would want it for racing, especially given 2) above

Finally, yes, I think I would still like them for commuting, but then again, I think my rim brakes do all I want, and a rim every 3 years is not so bad as I would probably replace the whole wheel if I had done high mileabes (plus, disc pads are generally more fiddly and costly).

Dont think we disagree maybe I was unclear

Y

rake

Bugly wrote:

alfablue wrote:

Bugly, re: above I would say:

1) for any given braking force there is no difference between rim or disc brakes - the forces are between rims, spokes and hubs, just the same, wherever the force originates from.

Yep you are correct however if a greater force is applied by the disk brake you would need beefier hub flanges and spoke count/weight. I was considering that DISC brake has greater force avaliable then caliper
2) I don't think so - I can already stop at eye-popping deceleration levels with rim brakes.

yes I agree the current technology is more then sufficient but again if we increase the braking we need to beef up the bike
3) I think I agree, few would want it for racing, especially given 2) above

Finally, yes, I think I would still like them for commuting, but then again, I think my rim brakes do all I want, and a rim every 3 years is not so bad as I would probably replace the whole wheel if I had done high mileabes (plus, disc pads are generally more fiddly and costly).

Dont think we disagree maybe I was unclear

Y

the forces are not the same for a given brake force. rim brakes dont transmit the braking load through the spokes trying to twist them round. because the diameter of the disc is much smaller than the rim diameter a much bigger force is needed to have the same effect at the tyre because of the leverage difference.these far higher forces are anchored at the thin end of the fork which is weaker than the crown.

Garry H

redddraggon wrote:

redddraggon wrote:

Garry H wrote:

whyamihere wrote:

Disc brakes are banned by the UCI.

Why is that?

Eddy Merckx and co didn't use them

This is largely the reason.

The only reason MTBing gets away with all this new technology because it's a rather new sport and doesn't really have the same sort of history.

I agree with you. None of the other reasons given would explain why they are banned, although plenty of reason are given as to why they may not be needed. Who do we think we are? If calipers were good enough for Eddy...

whyamihere

I'm surprised we're allowed dual pivot calipers to be honest. Eddy did fine on single pivots...

Fridge-Seal

Garry H wrote:

redddraggon wrote:

redddraggon wrote:

Garry H wrote:

whyamihere wrote:

Disc brakes are banned by the UCI.

Why is that?

Eddy Merckx and co didn't use them

This is largely the reason.

The only reason MTBing gets away with all this new technology because it's a rather new sport and doesn't really have the same sort of history.

I agree with you. None of the other reasons given would explain why they are banned, although plenty of reason are given as to why they may not be needed. Who do we think we are? If calipers were good enough for Eddy...

Forgive me, but that's insane, that's like saying that we (MTB'ers) shouldn't have the DW-Link because gary Fisher didn't have it when MTB'ing was in its infancy!

Garry H

Fridge-Seal wrote:

Forgive me, but that's insane, that's like saying that we (MTB'ers) shouldn't have the DW-Link because gary Fisher didn't have it when MTB'ing was in its infancy!

By jove you're right! Steps should be taken to ban them immediately