What’s wrong with Chris Froome’s disc brakes?

Which pads are you using?

The originals on the Spyres lasted a year and I'd have bought them again if I could. As it was, I bought whatever was on offer from Chain Reaction which turned out to be EBC which also seem excellent- I can't yet tell if they'll last a year as well!

I've got Shimano organic in the front caliper and EBC in the rear; they just howl at different pitches. I added copper grease to the back of the rear pads and it helped for a while. Might try that again.

they are currently RWD organic,though they seem to be out of stock everywhere at the moment, but the key rather than the brand,though Id never buy purely on price alone, for me was just picking organic compound pads.

the original pads that came with the bike werent very good and I swapped to organic and it fixed alot of the issues  Id had with them

my Spyre maintenance regime is I turn a screw every so often when the lever travel feels too long

You missed out the appalling and arduous task of changing the pads once a year after a lot of heavy use on big hills with a heavy trailer. I don't know how I've managed to cope, what with the occasional squeal on first braking in the rain, which then mostly disappears with subsequent braking. I really must go back to all those carefree rainy Lancashire days with all the mud and grit grinding away the rims while braking hardly works!

there arent any big hills in East Anglia I replace front pads maybe once a year, rears last maybe twice as long & its so simple a job, whereas my rim blocks constantly picking out ali pick up from the rim,literally seeing your rim disintegrate in front of your eyes, assuming it hadntly already jammed in the groove wear indicator of the rim, and trashed the blocks on your commute home.

 front pads maybe once a year, rears last maybe twice as long

That's interesting- I ave only a 1 1/4 year experience of discs, but both front and rear wore out at precisely the same time- the indication was a curious clicking noise from both. I couldn't work out the cause but it instantly resolved after quick pad change, and they were all equally worn.

On cable discs that click can be the return spring over-compressing. This can be solved with the pad adjusters on the Spyres. It happened to me on a serious descent - Kenmore Hill, 4 km average 9% and a really steep finish. Glad that the rear brake was still working.

I had been using barrel adjusters on the cables instead of the caliper screws to take up the pad wear, and that's wrong.

Tbf it's just an indicator of my own braking style,in that i bias to the fronts way more than the rears with discs,just because I find it easier to ride like that.

Consequently get very little wear on the rear pad.

Weirdly rim brakes totally different, I grab at both mostly equally,but with more rear bias instead.

Awavey wrote:

Tbf it's just an indicator of my own braking style,in that i bias to the fronts way more than the rears with discs,just because I find it easier to ride like that. Consequently get very little wear on the rear pad. Weirdly rim brakes totally different, I grab at both mostly equally,but with more rear bias instead.

I often find I start by applying boith equally, but if going downhill or braking hard I soon have to back off on the rear brake or the rear wheel locks up. Due to the weight and turning moment reactions pushing more weight onto the front wheel. I suppose backing off both brakes might also resolve the rear wheel locking while providing the same deceleration.

Perhaps if riding on the flat and always braking early and gradually wear might be more even. But then arguably rim brakes would be fine. Or conversly the lower levels of braking available on rim brakes reduce the weight transfer onto the front wheel, allowing more equal braking.

I've never locked up the front wheel unintentionally. 

I use a flat-head screwdriver to push pistons back in a bit, but I leave the pads in place so any damage is done to the pads and not the pistons. I have pushed the pistons themselves in the past, so I switched to using plastic tyre levers to minimise the damage. Personally, I don't see why damage to the face of the piston would make much difference as long as they move in and out properly.

Damage to the piston face could spread through the piston as it expands & contracts with the heat.

Thanks - I'll look out for that. I did trash one front caliper piston by pushing it out too far whilst I was botching a repair (IIRC I'd finished bleeding the brake and was pumping the brake a few times to get it calibrated, but hadn't remembered to put the front wheel back). I ended up replacing the whole caliper (approx £50) so at least I learnt how to do that.

Edit: remembered that that wasn't what broke it - I'd put the wheel back in and hadn't put the brake pads back in, so when I tried the lever on a spinning wheel, the pistons were pushed directly onto the spinning rotor. Dumb thing to do.

With ceramic pistons, you can crack the piston - did that once using a big flat screwdriver and learnt my lesson! I now use the same screwdriver, like you do though I leave the old pads in to do it, then remove and discard them.

Oh and regarding dedicated tools, the only dedicated tool you need for Shimano hydraulic discs is a bleed kit - 6 bolt rotors use either an Allen key or Torx and centre lock use a Shimano cassette tool. The hose can be cut square with a sharp craft knife, the insert hammered in with a small hammer if you don't have a dedicated press and the hose is tightened using an open ended spanner. Not sure which dedicated tools fwhite181 is actually complaining about?

PP

I had to get a special tool to undo the centrelock rotors as my cassette tool couldn't deal with the thru-axle hub and yes it's easy to hammer in the hose insert.

But that's the whole *point* behind disc brakes.  To create new problems so they can sell us new solutions.  We can now look forward to a decade of annual "this year's brakes are X% ligther and Y% more aero."  They'd already milked all they could out of wheels and frames so time to create new problems.  I bet most people never knew they had braking problems until Specialized, Trek, et al decided they needed a boost to their bottom line. 

Hydraulic discs already automatically calibrate themselves.  And of course, you'd never use cable discs...

So why is it that the pistons fire unequally?

slappop wrote:

So why is it that the pistons fire unequally?

Usually it's due to one of the pistons being a bit stuck and needing more force to get it to move.

The 'calibration' for pad wear is to do with a little hole which allows fluid to pass from the reservoir to the system when the lever isn't pulled, but which is closed when activating the lever which allows the pressure to be passed to the two pistons. As the pressure is applied equally to the pistons, the system is relying on both pistons working with similar friction.

So as I said, this is ripe for the addition of servos. In fact, not just for calibration - servo assist of the braking action itself would enable a wider gap and possibly goodies such as ABS and dynamically configurable feel.

Because one of them is meeting resistance, usually from crud build up. It is pretty rare for one to sieze solid if used regularly and cleaned every so often.

PP

They automatically adjust for wear, but for lazy pistons?