watch this space (CX disk brakes)

roger_merriman

http://www.bikeradar.com/news/article/uci-allows-disc-brakes-for-cyclo-cross-26660

This is good thing and should make the CX a even better all rounder. brakes being a issue for CX.

and who knows might well mean roadie disks, which has been a long time coming.

Roastie

Absolutely! Will also mean a much better choice of disc brake compatible forks (this is a serious problem at the moment).

supersonic

Should allow MTBs lol.

Roastie

The new rules allow a max of 33mm width rubber, ...

That said, MTBs have always been welcome at non-UCI CX races.

Jay dubbleU

Genesis vindicated ??

always_tyred

Jay dubbleU wrote:

Genesis vindicated ??

And Fixie Inc, and Everti, and Kona and Salsa....

The best part of this is that the brakes themselves will get better. Before long, we will have hydraulic brake compatible drop bar sti's.

The wheels will get lighter as well.

Fabulous news.

Of course, I was well ahead of the curve. 8)

gabriel959

I personally don't think we need disc brakes on a road bike, hydraulic brakes though that would be great.

always_tyred

gabriel959 wrote:

I personally don't think we need disc brakes on a road bike, hydraulic brakes though that would be great.

A while ago, I saw an article about a prototype hydraulic brake lever for a road bike and, wait for it, hydraulic shifting.

spasypaddy

i wouldnt want hydraulics on a road bike, think of the weight
:shock:

always_tyred

spasypaddy wrote:

i wouldnt want hydraulics on a road bike, think of the weight
:shock:

? Don't you think that hydraulic fluid would be lighter than a metal cable?

Stevo_666

roger merriman wrote:

http://www.bikeradar.com/news/article/uci-allows-disc-brakes-for-cyclo-cross-26660and who knows might well mean roadie disks, which has been a long time coming.

There was an article recently on a heinously expensive road bike that is in production (can't remember the name off the top of my head) - it had disc brakes. I reckon once the cost of a decently light disc system for road bikes has been reduced enough, it will become more commonplace.

spasypaddy

no. the cable is very thin and light.

whyamihere

supersonic wrote:

Should allow MTBs lol.

I think they do... Wheel size must be at least 55cm, MTBs run on 59cm. Discs are allowed now. Can't be bothered to go through the entire rule book to see what handlebars are allowed. An MTB would have basically no chance in a CX race though.

supersonic

I think you can run CX bikes in XC bikes under UCI rules mind.

always_tyred

spasypaddy wrote:

no. the cable is very thin and light.

I know what it is, my bike has them. Pretty sure its a bundle of metal strands. How much hydraulic fluid do you think you would need? Road bikes wouldn't need the same braking power as a mountain bike. Very low forces are required for shifting. There's no reason it couldn't be lighter than current mechanical setups. Cheaper? More reliable? Different questions entirely. Overtaken by electronic shifting? Probably.

Mmm... electronic shifting and hydraulic braking....

supersonic

Brake calipers and rotors tend to add some weight in though. The lightest cable brakes are lighter than the lightest hydros at the minute, including all the paraphenalia to fit them. And a lot lighter on average.

whyamihere

Weight's a red herring. In muddy conditions compared to rim brakes, hydraulic discs probably halve the braking distance (note: I haven't actually done the measurement). Cable discs are better than rim brakes, but not as good as hydraulic discs. This better braking more than makes up for the weight penalty. Looking at cross country mountain bike racers, at the very driest events you may see some rim brakes still knocking about, but as soon as there's mud, everyone's on hydraulic discs. Cyclocross is a winter sport, it's always muddy.

jimmypippa

On a related thought, I do wonder how much the UCI has slowed the development of bicycles.

One thing that got me thinking is that a recumbent *tricycle* holds the Lands End to John O Groat's cycling record. Shouldn't recumbent bicycles be faster still?

Aidy

whyamihere wrote:

Weight's a red herring. In muddy conditions compared to rim brakes, hydraulic discs probably halve the braking distance (note: I haven't actually done the measurement). Cable discs are better than rim brakes, but not as good as hydraulic discs. This better braking more than makes up for the weight penalty. Looking at cross country mountain bike racers, at the very driest events you may see some rim brakes still knocking about, but as soon as there's mud, everyone's on hydraulic discs. Cyclocross is a winter sport, it's always muddy.

Not to mention how much having your brakes full of mud slows you down.

always_tyred

supersonic wrote:

Brake calipers and rotors tend to add some weight in though. The lightest cable brakes are lighter than the lightest hydros at the minute, including all the paraphenalia to fit them. And a lot lighter on average.

You mean that mountain bike brakes and rotors are heavier than road bike brakes? So are mountain bike saddles, wheel rims and frames.

A melon is, I believe, heavier than a banana.

Discs would have advantages - lower inertia wheels - move the braking surface from the rim to the hub means a lighter rim and weight closer to the axis of rotation.

I don't think it will happen for a long time in road bikes, but development for cross will be a first step.

Roastie

whyamihere wrote:

Weight's a red herring. In muddy conditions compared to rim brakes, hydraulic discs

Probably not far from the truth. Having raced my proto in the London CX champs early this year, I was hugely impressed with the improvement in braking, but more important the improved level of control, from discs compared to canti's in muddy race conditions.

As for hydraulics v cable. I think cable will stay for the forseeable. It works well and the performance improvement argument isn't really there yet (for cross anyways).

I think the biggest improvements will be in lighter, disc specific wheels, particularly rims - tho' I think lighter CX specific hubs may pop up too. I think there will be a resurgence of availability of 140mm rear discs. The range of road-specific calipers will increase. And the range of forks available will improve - at the moment there are very few options.

spasypaddy

Always Tyred wrote:

spasypaddy wrote:

no. the cable is very thin and light.

I know what it is, my bike has them. Pretty sure its a bundle of metal strands. How much hydraulic fluid do you think you would need? Road bikes wouldn't need the same braking power as a mountain bike. Very low forces are required for shifting. There's no reason it couldn't be lighter than current mechanical setups. Cheaper? More reliable? Different questions entirely. Overtaken by electronic shifting? Probably.

Mmm... electronic shifting and hydraulic braking....

so fluid to the back brake will be lighter than a cable to the back brake. i doubt it.

ex-pat scot

can't wait, as this should encourage proper "trickle down" road disc development that should pay dividends for winter commuters and tourers.

I would love mechanical discs on my hack bikes, at least on the front, for bad weather.
This winter, with the extended slush and snow periods, has really exposed the weaknesses of rim braking.

always_tyred

spasypaddy wrote:

Always Tyred wrote:

spasypaddy wrote:

no. the cable is very thin and light.

I know what it is, my bike has them. Pretty sure its a bundle of metal strands. How much hydraulic fluid do you think you would need? Road bikes wouldn't need the same braking power as a mountain bike. Very low forces are required for shifting. There's no reason it couldn't be lighter than current mechanical setups. Cheaper? More reliable? Different questions entirely. Overtaken by electronic shifting? Probably.

Mmm... electronic shifting and hydraulic braking....

so fluid to the back brake will be lighter than a cable to the back brake. i doubt it.

So people keep saying, but why? Argue your point. You would be comparing a length of a metal cable running inside a metal tube surrounded by a plastic outer, with hydraulic equivalents, plus a small reservoir.

Hydraulic fluid is lower density than metal and you wouldn't need a much greater cross sectional area of hydraulic fluid.

There's a general technical prejudice against the idea, but if optimised to the same extent as current road mechanical systems, I've not yet heard a good reason why they wouldn't be superior in every way.

The only like for like comparison currently available is mountain bike mechanical disc systems vs. mountain bike hydraulic systems. Which is heavier?

spasypaddy

i cant find anywhere that says how much a disc brake with cable or a disc brake with fluid weighs. (well not anywhere that states that the weight is including cable/fluid). It stands to reason that the stated weight for a disc brake using fluid will be lighter than the stated weight for a disc brake using cable because the brake using fluid is a higher end brake. I am doubtful of the stated weight including the fluid/cable.

always_tyred

spasypaddy wrote:

i cant find anywhere that says how much a disc brake with cable or a disc brake with fluid weighs. (well not anywhere that states that the weight is including cable/fluid). It stands to reason that the stated weight for a disc brake using fluid will be lighter than the stated weight for a disc brake using cable because the brake using fluid is a higher end brake. I am doubtful of the stated weight including the fluid/cable.

Its entirely possible that you are right, but the only fact there is that its possible to make hydraulic systems which are lighter than mechanical systems. Why is it such a leap of faith to presume that the same could apply to road or CX brakes?

spasypaddy

because i dont want to have to spend the money to upgrade

therefore im going to blindly believe that its heavier (until proved otherwise)

Roastie

spasypaddy wrote:

i cant find anywhere that says how much a disc brake with cable or a disc brake with fluid weighs. (well not anywhere that states that the weight is including cable/fluid). It stands to reason that the stated weight for a disc brake using fluid will be lighter than the stated weight for a disc brake using cable because the brake using fluid is a higher end brake. I am doubtful of the stated weight including the fluid/cable.

I think the cable will always be lighter - fluid needs a hose to contain it. The cable can run for fairly long runs in air between cable stops - so the outer required is far less. For cross, I don't see hydraulics taking over (I could be wrong tho'); more likely is a lot more effort going into making lighter cable calipers. The BB7 has a lot of excess that could be shaved ... Bring on SRAM red BB disc calipers .

mudcovered

Roastie wrote:

The BB7 has a lot of excess that could be shaved ... Bring on SRAM red BB disc calipers .

That and the likely development of a lot of good CX disc specific forks (as you have already said) is very good news. I still get a moment of terror when pulling on the brake lever of a rim braked bike in the wet and get the initial 0 response.

Mike

spasypaddy

would a carbon fork work with a disc brake or would it sheer off?

mudcovered

spasypaddy wrote:

would a carbon fork work with a disc brake or would it sheer off?

Can't see any reason it can't be done. MTB frame designers seem to manage to make rear triangles on carbon framed MTBs resist these forces. Front brake forces are higher but still don't see any reason why it can't be done.

It isn't quite as simple as just molding on a mount though as you do need to adjust this carbon layup to resist the braking forces on the fork leg. This is why the UCI making them legal is good news as it means that the CX fork manufacturers will spend the necessary research money to make them. Up until now the demand (and therefore the development money available) is not very high as the market is restricted to a fairly small group.

Mike