FAO disk brake lovers...

meanredspider

bails87 wrote:

MRS: seen this?

4 piston DH brakes on a Di2 road bike....? :twisted:

I did - someone posted it on the Volagi Owners FB page. I need to be convinced of the overall benefits of hydraulic brakes over mechanical for a road bike. I was really interested to hear the views of the downhiller I work with on BB7s saying they're pretty much as good as anything. The self-adjusting nature of hydraulic is a plus (especially in incredibly muddy (The Puffer!) conditions) but hardly a consideration for me. There's more flexibility in routing hydraulic pipes though bleeding is a downside. Freezing is a plus though heat dissapation possibly a downside. Any views?

I'm pretty sure discs will go hydraulic just from a standardization POV and the calipers may well go smaller & lighter than mechanical

sketchley

What are the benefits of hydraulic over cable on an MTB?

bails87

Sketchley wrote:

What are the benefits of hydraulic over cable on an MTB?

Zero cable drag, so better feel, plus they can't get gunked up. They also self adjust, so you push the pistons all the way back when you put new pads in and that's it. As the pads wear, the pistons automatically move further out. So they always feel the same.

The BB5s on my CX are fine, because the demands on the road are generally less than MTBing. But for MTBing I would always choose hydraulics. That might be because I've only ever used rubbish cable discs off roads, BB7s may be a real revelation, but I don't know anyone who uses them, hydros are the default choice. Perhaps wrongly, of course.

veronese68

Do cable disc calipers only act on one side so relying on a sliding caliper? With hydraulics it's easy to operate both pistons. Another thing about hydraulics over cable if you have hydraulics you can run multi piston calipers, so having a larger friction area. I think with a cable set up a 4 pot caliper would be harder to make work so limiting pad size.

bails87

Yep, good point. I believe there are some cable discs that pull both pads, and possibly some very very basic hydraulics that only push one side, but for 99% of them, cable move one side, hydro move both.

meanredspider

I don't think the benefits of hydraulics translate quite as well to a road set-up. Pad wear on The Puffer meant that some people have needed to change pads (even sintered pads) every 12 miles! The self-adjusting feature comes into its own. Equally, over-braking an MTB so that very little braking effort is required means far less fatigue on a technical descent and more modulation. Downhill bikes are also heavy and the riders are armoured so bigger brakes are needed.

sketchley

@MRS I know this is subjective and depends on when and where you ride but what's is your estimate for how often you will need to replace pads, rotors etc and how does this compare to callipers. Appreciate the answer might be "I don't know yet ask me in 6 months". Of course any replacement of disk part can be tempered against lack of rim wear....

bails87

Sketchley wrote:

@MRS I know this is subjective and depends on when and where you ride but what's is your estimate for how often you will need to replace pads, rotors etc and how does this compare to callipers. Appreciate the answer might be "I don't know yet ask me in 6 months". Of course any replacement of disk part can be tempered against lack of rim wear....

For an MTB, discs last a very, very long time.

Pads can get wrecked in a single ride if they're not bedded in, but that's MTBing. My CX's pads must have at least 3/4s of their depth left, and I've been commuting 3 times a week (15+ miles each way) on it since October.

essex-commuter

bails87 wrote:

My CX's pads must have at least 3/4s of their depth left, and I've been commuting 3 times a week (15+ miles each way) on it since October.

I've just gone past the 4000 mile mark on my CX, I took the pads out to clean a couple of weeks ago and a rough estimate is that they are 50% worn. I've got a set of organics ready, going to give them a try next.

nicklouse

meanredspider wrote:

Downhill bikes are also heavy and the riders are armoured so bigger brakes are needed.

Sorry but no.

Some use small brakes. It all depends on where why and what.

If you don't need to scrub of a lot of speed very quickly why use big brakes?

At some races we ran 160 front 140 rear. Others 203 front and 140 or 160 rear. When just playing around then 203/203 or 180.

If you brake you just have o accelerate again.

Some riders even took angle grinders to their pads o reduce the power.

meanredspider

bails87 wrote:

Sketchley wrote:

@MRS I know this is subjective and depends on when and where you ride but what's is your estimate for how often you will need to replace pads, rotors etc and how does this compare to callipers. Appreciate the answer might be "I don't know yet ask me in 6 months". Of course any replacement of disk part can be tempered against lack of rim wear....

For an MTB, discs last a very, very long time.

Pads can get wrecked in a single ride if they're not bedded in, but that's MTBing. My CX's pads must have at least 3/4s of their depth left, and I've been commuting 3 times a week (15+ miles each way) on it since October.

Yup - I really have no clue. I've done hundreds of miles on my MTB on the road without needing to change the (organic) pads. 5 laps of the Puffer (30 miles) in mud and crap & I'd seen a pair of (bedded in) sintered pads. It's far too early to say on the Volagi but I'm guessing a very long way. I did one adjustment after they'd bedded in and I've not touched them since

rick_chasey

nicklouse wrote:

meanredspider wrote:

Downhill bikes are also heavy and the riders are armoured so bigger brakes are needed.

Sorry but no.

Some use small brakes. It all depends on where why and what.

If you don't need to scrub of a lot of speed very quickly why use big brakes?

At some races we ran 160 front 140 rear. Others 203 front and 140 or 160 rear. When just playing around then 203/203 or 180.

If you brake you just have to accelerate again.

.

Heaven forbid! MTBers having to pedal!

meanredspider

nicklouse wrote:

meanredspider wrote:

Downhill bikes are also heavy and the riders are armoured so bigger brakes are needed.

Sorry but no.

Some use small brakes. It all depends on where why and what.

If you don't need to scrub of a lot of speed very quickly why use big brakes?

At some races we ran 160 front 140 rear. Others 203 front and 140 or 160 rear. When just playing around then 203/203 or 180.

If you brake you just have o accelerate again.

Some riders even took angle grinders to their pads o reduce the power.

No, downhill bikes aren't heavier than road bikes???? That's my point.

I accept you don't need big brakes all the time but I can confidently predict that road bikes will never have 203 front brakes (the Colnago has 140/140). Another data point is that there are specific very soft DH pads.

chilling

I think the only reason all bikes don't have disks is because of the UCI. I'm sure that Cadel would have them on his bike for the descents, he's a mountain biker after all. I bet he know's the advantages. Advantages recognised by pretty much every other wheeled sport, F1, Moto GP, etc. I guarantee that if there was a better way of braking they would be using it.

One incident that demonstrated the difference to me was when a girl stepped out into the road in front of me without looking. I grabbed the brakes and only just stopped in time. The roadie behind me piled into the back of me.

'Sorry mate, just couldn't stop in time' is what he said.

Which is fair enough. The cause could be any number of things he didn't react in time, I had more grip, my brakes were better It was a bit damp that day too.

I'd buy a disk fit roadie tomorrow if I could afford one.

supersonic

If they did allow disc brakes in the UCI, I can see very little using them for road race. Though would be nice to have the choice.

I have never felt the need for discs on any of the road riding I have done, in any conditions. Even off road, the majority of my riding is good enough with V brakes.

meanredspider

I don't know if this link will work

https://www.facebook.com/photo.php?fbid=3178282088788&set=o.162315693876818&type=1&ref=nf

It's basically the regs for the Levi's GranFondo strongly discouraging the use of carbon clinchers for the event because of the high risk of failure of these wheels with the braking required.

I'm sure if you are ploughing across the Fens or parts of Northern France, Belgium or Holland, disc brakes seem unnecessary. That said, I've yet to hear a compelling argument against them. They add about 200-300g to the weight of a bike (the Volagi is 7.5kg) and £30-£40 to the price - the price and weight of a thin baselayer.

supersonic

They add about 200-300g to the weight of a bike

For what price though? At top end race, price is a moot point when the sponsors pick up the tab. But if we bring it back to the masses... on a 1k bike they will be heavier, cost more than cantis, resulting in lower spec elsewhere which will further up the weight.

meanredspider

supersonic wrote:

For what price though? At top end race, price is a moot point when the sponsors pick up the tab. But if we bring it back to the masses... on a 1k bike they will be heavier, cost more than cantis, resulting in lower spec elsewhere which will further up the weight.

As I say, they should add no more than £30-£40 to the price of the bike - and as volumes go up, cost will come down. Realistically 200-300g doesn't make a difference to most of us - the weight of a thin baselayer. Braking, though, does make a big difference to us 1k bike riders. I for sure have had situations where I'm hauling on my 105 brakes and not stopping as quick as I'd like (or need)

roger_merriman

Rick Chasey wrote:

nicklouse wrote:

meanredspider wrote:

Downhill bikes are also heavy and the riders are armoured so bigger brakes are needed.

Sorry but no.

Some use small brakes. It all depends on where why and what.

If you don't need to scrub of a lot of speed very quickly why use big brakes?

At some races we ran 160 front 140 rear. Others 203 front and 140 or 160 rear. When just playing around then 203/203 or 180.

If you brake you just have to accelerate again.

.

Heaven forbid! MTBers having to pedal!

with 22t to 34t I'll ride up hills steeper than hardknott, and with rocks and wet roots etc. and I enjoy it ;-)

bails87

roger merriman wrote:

Rick Chasey wrote:

nicklouse wrote:

meanredspider wrote:

Downhill bikes are also heavy and the riders are armoured so bigger brakes are needed.

Sorry but no.

Some use small brakes. It all depends on where why and what.

If you don't need to scrub of a lot of speed very quickly why use big brakes?

At some races we ran 160 front 140 rear. Others 203 front and 140 or 160 rear. When just playing around then 203/203 or 180.

If you brake you just have to accelerate again.

.

Heaven forbid! MTBers having to pedal!

with 22t to 34t I'll ride up hills steeper than hardknott, and with rocks and wet roots etc. and I enjoy it ;-)

I thought Rick misunderstood anyway. I took nick to mean that if you brake during a race then you're not going as fast as you could be going if you just used a little chutzpah to go round the corner.

rick_chasey

roger merriman wrote:

Rick Chasey wrote:

Heaven forbid! MTBers having to pedal!

with 22t to 34t I'll ride up hills steeper than hardknott, and with rocks and wet roots etc. and I enjoy it ;-)

Yeah yeah. When it comes to actual mountains for MTBers, they all get very lazy

Stevo_666

Rick Chasey wrote:

roger merriman wrote:

Rick Chasey wrote:

Heaven forbid! MTBers having to pedal!

with 22t to 34t I'll ride up hills steeper than hardknott, and with rocks and wet roots etc. and I enjoy it ;-)

Yeah yeah. When it comes to actual mountains for MTBers, they all get very lazy

It's called "having fun", you should try it sometime ;-)

rick_chasey

Stevo 666 wrote:

It's called "having fun", you should try it sometime ;-)

Fun?

What the hell is fun?

Never heard of it :P.

rjsterry

roger merriman wrote:

Rick Chasey wrote:

nicklouse wrote:

meanredspider wrote:

Downhill bikes are also heavy and the riders are armoured so bigger brakes are needed.

Sorry but no.

Some use small brakes. It all depends on where why and what.

If you don't need to scrub of a lot of speed very quickly why use big brakes?

At some races we ran 160 front 140 rear. Others 203 front and 140 or 160 rear. When just playing around then 203/203 or 180.

If you brake you just have to accelerate again.

.

Heaven forbid! MTBers having to pedal!

with 22t to 34t I'll ride up hills steeper than hardknott, and with rocks and wet roots etc. and I enjoy it ;-)

I should hope you could winch yourself up a cliff face with gearing that low. @Stevo 666: different definition of fun is all - it's nice to feel you've earned that descent.

rick_chasey

rjsterry wrote:

I should hope you could winch yourself up a cliff face with gearing that low. @Stevo 666: different definition of fun is all - it's nice to feel you've earned that descent.

Let's face it, we're kinkier.

We get kicks out of the lycra and suffering.

rjsterry

Rick Chasey wrote:

rjsterry wrote:

I should hope you could winch yourself up a cliff face with gearing that low. @Stevo 666: different definition of fun is all - it's nice to feel you've earned that descent.

Let's face it, we're kinkier.

We get kicks out of the lycra and suffering.

Yeah, who am I kidding. At least we don't have a mud fetish.

rick_chasey

rjsterry wrote:

Rick Chasey wrote:

rjsterry wrote:

I should hope you could winch yourself up a cliff face with gearing that low. @Stevo 666: different definition of fun is all - it's nice to feel you've earned that descent.

Let's face it, we're kinkier.

We get kicks out of the lycra and suffering.

Yeah, who am I kidding. At least we don't have a "mud" fetish.

Corrected.

roger_merriman

supersonic wrote:

If they did allow disc brakes in the UCI, I can see very little using them for road race. Though would be nice to have the choice.

I have never felt the need for discs on any of the road riding I have done, in any conditions. Even off road, the majority of my riding is good enough with V brakes.

For my self disk brake make very good sense, i'm mostly riding in wet places, I have a knack of finding mud!

and the areas I ride are fairly gritty soil that wears out rim pads quickly quick.

rjsterry wrote:

At least we don't have a mud fetish.

Ah that would be me!

The Rookie

I like running discs on the commuter, as a rarely have to touch the brakes it's nice knowing I won't travel over a metre before the rims are dry enough to do anything.

Alligator lightweight discs, cheap clarkes organic pads, 2000 miles and no obvious wear.....

Also I bought a frame that was disc only and it's nice to use MTB kit as it's interchangeable with the MTB!

Simon

meanredspider

Rick Chasey wrote:

It's a bit of a bu99er when your bike falls off though! (mind you, he doesn't seem too bothered...)