How do I know when brake discs need replacing?

mrb123
mrb123 Posts: 4,616
edited February 2017 in Workshop
Apologies for a probably stupid question, but I'm a novice as far as disc brakes are concerned.

How do I know when the pads need replacing? The brakes are TRP Spyres. It's pretty much impossible to get any visual idea with the pads on the bike as far as I can tell, particularly as I've got a rack and mudguards on.

Do they start making a grinding noise like car discs do or should I be taking the pads off occasionally to inspect them?

Comments

  • smoggysteve
    smoggysteve Posts: 2,909
    When you fail to stop
  • mrb123
    mrb123 Posts: 4,616
    SmoggySteve wrote:
    When you fail to stop

    Thanks for the advice. I've managed to stop so far so they must be OK.
  • zefs
    zefs Posts: 484
    The manual states that you need to replace them when they reach 0.8mm so you should check them often as it's dangerous to use them past that point.
  • compuwiz_uk
    compuwiz_uk Posts: 139
    can you not look from the underside of the caliper ( armed with torch if needed ) to check for general pad thickness if inspection from above is problematic.

    once they get really low then they will be best checked out of the caliper ( or changed out if you think they are that low )

    if still not easily visible then a wheel out may give you a better view of the pads too & may be quicker than removing the pads to check them.
  • cycleclinic
    cycleclinic Posts: 6,865
    I have a rack and guard on my bike and i manage to see the ammount of pad left.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • mrb123
    mrb123 Posts: 4,616
    compuwiz_uk wrote:
    can you not look from the underside of the caliper ( armed with torch if needed ) to check for general pad thickness if inspection from above is problematic.

    once they get really low then they will be best checked out of the caliper ( or changed out if you think they are that low )

    if still not easily visible then a wheel out may give you a better view of the pads too & may be quicker than removing the pads to check them.

    Thanks, I think I'll have another look later with a torch and maybe then consider taking them off. I'm going to need to learn how to remove and replace them sooner or later!
  • mrb123
    mrb123 Posts: 4,616
    oxoman wrote:
    Go on park tools website or type into youtube the task you want to do and low and behold there will be loads of easy to follow clips.

    Will do, thanks.

    I found this article which seems to be a fairly easy to follow description of what to do

    https://www.google.co.uk/amp/s/accident ... liper/amp/

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