FAO disk brake lovers...

rick_chasey

Enjoy.

dunnnooo

*gibbers*

*cuts out kidney*

mudcow007

Holy Moly!

thats rather tasty.....

nicklouse

why did they not put the brake on the front of the fork?
it would have eliminated possible wheel issues with lightweight Ti carbon Qrs.

rjsterry

nicklouse wrote:

why did they not put the brake on the front of the fork?
it would have eliminated possible wheel issues with lightweight Ti carbon Qrs.

Because it wouldn't be as pretty - looks trump practicality.

Paul E

Moist

sketchley

nicklouse wrote:

why did they not put the brake on the front of the fork?
it would have eliminated possible wheel issues with lightweight Ti carbon Qrs.

Are these the same "issues" mentioned here http://www.ne.jp/asahi/julesandjames/ho ... index.html keen to understand more about that.

bonkstrong

5 replies and nobody has menioned the use of DA on an Italian bike?? I'm not angry, I'm just very disappointed...

veronese68

I'm off to buy a lottery ticket.

Aidy

nicklouse wrote:

why did they not put the brake on the front of the fork?
it would have eliminated possible wheel issues with lightweight Ti carbon Qrs.

Surely it makes more sense for the calliper to push against the fork leg than pull away from it?

bails87

Aidy wrote:

nicklouse wrote:

why did they not put the brake on the front of the fork?
it would have eliminated possible wheel issues with lightweight Ti carbon Qrs.

Surely it makes more sense for the calliper to push against the fork leg than pull away from it?

But the caliper acts as a pivot, pushing the axle down.....out of the dropouts.

Paul E

Sketchley wrote:

nicklouse wrote:

why did they not put the brake on the front of the fork?
it would have eliminated possible wheel issues with lightweight Ti carbon Qrs.

Are these the same "issues" mentioned here http://www.ne.jp/asahi/julesandjames/ho ... index.html keen to understand more about that.

I remember that, isn't that where the term for lawyers lips comes from on forks now to stop that happening? or is that a different case?

As for DA being on an Italian bike, does it really matter that much???? or is it pure snobbery!

rick_chasey

bails87 wrote:

Aidy wrote:

nicklouse wrote:

why did they not put the brake on the front of the fork?
it would have eliminated possible wheel issues with lightweight Ti carbon Qrs.

Surely it makes more sense for the calliper to push against the fork leg than pull away from it?

But the caliper acts as a pivot, pushing the axle down.....out of the dropouts.

Spot the MTBers.

meanredspider

Of course I totally love this. Road bike with disc brakes and Di2: where have I seen that before? Glad they are catching up.

Someone with have to explain the issue with the caliper positioning - I though all disc brakes were position there...

il_principe

Wrongness.

bails87

Yep, I'm sure that's where 'lawyer lips' come from.

Not a problem on my MTB with a 20mm Maxle (through axle), but if you were to use an undertightened QR then it may cause a problem.

sketchley

meanredspider wrote:

Of course I totally love this. Road bike with disc brakes and Di2: where have I seen that before? Glad they are catching up.

Someone with have to explain the issue with the caliper positioning - I though all disc brakes were position there...

Simply put road vibration *may* cause a QR skewer to come slightly loose (disk brake or not), normally this isn't a problem as downward pressure on the axle from your weight stops the wheel coming out. But a disc brakes acts as pivot so that when you apply the brake downward pressure is applied to the axle. Combine these two effect can cause catastrophic failure (i.e. wheel comes out). There are solutions to the problem including mounting the disk brake so it applies upwards pressure. There maybe other technical solution I'd ask Volagi if you are concerned, but recommend a frequent check to make sure QR is tight.

meanredspider

bails87 wrote:

But the caliper acts as a pivot, pushing the axle down.....out of the dropouts.

To push them out of the dropouts, the caliper would have to be at (or even below, as the dropouts face forward) the horizontal line of the QR. In the position the brake is in, the reaction at the QR will be broadly backwards - and pretty much exactly the same as a conventional caliper on a road bike.

sketchley

More here, doesn't look like Lawyer lips are enough in themselves...

http://en.wikipedia.org/wiki/Dropout_%2 ... awyer_lips

Fat-Boy-Roubaix

Darn your quick posting was just going to post pics, but why no mudguard mounts they missed a trick there

davis

I'm gonna be shouted at for this... but I'm not keen. I've never been a huge fan of Colnagos.

I prefer meanredspider's Volagi. So there.

bails87

MRS:
Normal rim brakes are above and in front of the axle, so braking pushes the axle up and bacwkards. Into the dropout.

A disc caliper is behind and above the axle, so the axle is pushed down and backwards when braking. Backwards is good, now that dropouts slope forwards, but down is bad. MAybe that's also why forks now have angled, rther than 'straight down' dropouts?

Aidy

Rick Chasey wrote:

Spot the MTBers.

Yes, and?

il_principe

davis wrote:

I'm gonna be shouted at for this... but I'm not keen. I've never been a huge fan of Colnagos.

I prefer meanredspider's Volagi. So there.

I'm kinda with you here. I love the paintwork on most of them, but remain unconvinced that lugged is better than say Monocoque.

meanredspider

I'd love to see the force analysis that suggests that this is much (if any) worse than conventional brakes. For starters, the load transfer under exactly this braking (especially on a road bike) is straight down through the fork (hence why it's so easy to lock a rear tyre). If this issue was real, the problem would be far more prevailent on MTBs where the offset of the caliper is extended by the shocks and the loads are much higher (bigger tyre contact patch)

bails87

Il Principe wrote:

davis wrote:

I'm gonna be shouted at for this... but I'm not keen. I've never been a huge fan of Colnagos.

I prefer meanredspider's Volagi. So there.

I'm kinda with you here. I love the paintwork on most of them, but remain unconvinced that lugged is better than say Monocoque.

Hadn't noticed that. I was distracted by the horrible grey!

sketchley

meanredspider wrote:

I'd love to see the force analysis that suggests that this is much (if any) worse than conventional brakes. For starters, the load transfer under exactly this braking (especially on a road bike) is straight down through the fork (hence why it's so easy to lock a rear tyre). If this issue was real, the problem would be far more prevailent on MTBs where the offset of the caliper is extended by the shocks and the loads are much higher (bigger tyre contact patch)

Look in the first link I posted, it goes in to some detail... I'd been interested it what Volagi say about it....

Fat-Boy-Roubaix

Yeah I still prefer the Volagi, but this is a good indicator of what is on its way. For Colnago to release a disc C59 can only be a matter of time for the other brands to follow suit, and then I would guess we are not far from UCI approving them.

I would would have a little bet that Specilaized will have a 2013 Roubaix with Discs and Guards with simialr paint job to the Volagi...

stuaff

I'd have it, great bike, and discs do have serious advantages, but a monocoque or tube-to-tube frame would look better.

meanredspider

bails87 wrote:

MRS:
Normal rim brakes are above and in front of the axle, so braking pushes the axle up and bacwkards. Into the dropout.

A disc caliper is behind and above the axle, so the axle is pushed down and backwards when braking. Backwards is good, now that dropouts slope forwards, but down is bad. MAybe that's also why forks now have angled, rther than 'straight down' dropouts?

We're talking degrees - less if you consider TT bikes with brakes behind the fork. MTB set-ups are FAR worse - was just looking at the set-up on my Cube Reaction - pretty much perfectly designed to create this problem - yet I don't hear of hundreds of Cube riders losing front wheels - despite hydraulic brakes, bigger discs, fatter tyres etc.

I have absolutely no concern about this - it's a non-issue

rjsterry

bails87 wrote:

MRS:
Normal rim brakes are above and in front of the axle, so braking pushes the axle up and bacwkards. Into the dropout.

A disc caliper is behind and above the axle, so the axle is pushed down and backwards when braking. Backwards is good, now that dropouts slope forwards, but down is bad. MAybe that's also why forks now have angled, rther than 'straight down' dropouts?

Just had a look at my bike and the calipers are not in front of the axle. If you take a line from the axle parallel to the steerer it passes through the centre of the brake pads - the reaction under braking will make the axle swing backwards and slightly down along an arc centred on the pads (assuming the calipers are rigid enough.