I don't understand my hydro disc brakes !!!

paulbnix
paulbnix Posts: 632
edited November 2018 in Workshop
I have a Canondale Synapse with a SRAM Rival 22 hydro groupset.

I have two sets of pads currently. One is the SRAM original and the other is a Wiggle lifeline set.

Whichever brake I fit the SRAM pads to has a lot more lever movement before the brake starts to bite.

I have measured the pads and the total depth of pad and backing plate is 3.6mm for the SRAM and 3.9mm for the Wiggle.

Can that 0.3mm make that much difference to the lever movement?

According to SRAM
Hydraulic disc brakes automatically adjust for brake pad wear. As hydraulic disc brake pads wear down and become thinner, caliper pistons advance to compensate.

That doesn't seem to be happening in my case.

Comments

  • penguin_of_death
    penguin_of_death Posts: 219
    Do you have a pad spacer? The pads have to move quite a bit to auto adjust. If you take the wheel out and pull the levers a couple of times so the pads are almost touching and then use the spacer it should move a little more fluid from the reservoir into the system.
    Look for "Advancing Pads"
  • paulbnix
    paulbnix Posts: 632
    Penguin of Death wrote:
    Do you have a pad spacer? The pads have to move quite a bit to auto adjust. If you take the wheel out and pull the levers a couple of times so the pads are almost touching and then use the spacer it should move a little more fluid from the reservoir into the system.
    Look for "Advancing Pads"
    It turned out that the pistons must have been a bit gunged up and not sliding over the seals properly.
    It’s the winter bike so not been used much in since April. Probably an idea to give them a clean at the end of winter.
    I cleaned them up and applied a bit of hydro fluid to them and they moved easier.
    The brakes now auto adjust to the same position.
    Unfortunately I’ve ended up with a bit of brake rub at the front. Maybe tomorrow’s ride will sort that.
  • paulbnix
    paulbnix Posts: 632
    After cleaning the pistons and adjusting the brake lever position I now have front and rear brakes that work.

    So I’m looking at getting some pads ready for the time when I need them.

    Looking at the available options there seems to be ceramic, semi metallic, sintered and SRAM originals (the dearest of course). What are the differences?
  • buckmulligan
    buckmulligan Posts: 1,031
    This article tells you everything that you need to know about brake pad compounds:

    https://www.merlincycles.com/blog/buyer ... rake-pads/

    I go for organic pads and still get years of life out of them on the road. YMMV.

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