How to measure disc brake pad thickness
Results 1 to 14 of 14
  1. #1
    Neophyte
    Reputation: jetdog9's Avatar
    Join Date
    Jul 2007
    Posts
    1,945

    How to measure disc brake pad thickness

    Are folks using any special caliper or fancy digital tool to measure pad thickness, or just a ruler, or just eyeballing things?

    When you measure, are you taking the pads out of the brake (seems like pain)? Or just stick a flashlight on them to see better?

    I'm on TRP Spyres... minimum thickness is supposedly 0.8 mm. New pads start around 2 mm, and it looks like I'm down to about 1 mm. Should I just go ahead and change them or squeeze some extra miles?

    Interestingly, and I could be totally wrong if I'm measuring poorly, looks like my back pads are a hair thinner than front, totally opposite of what I'd expect.

    For the record, mixed terrain riding, a few wet rides but not a ton, definitely some steep descents where the brakes are used a lot, took about 700 miles over 15 months to get from 2 mm to 1 mm.

  2. #2
    RoadBikeReview Member
    Reputation:
    Join Date
    Nov 2013
    Posts
    661
    I think you're over-analyzing this. Pull the pads and if they're getting thin, replace them. Heck, you're going to be replacing them no matter what, order some new ones, put 'em on, and enjoy riding this Spring w/o worrying about your brake pads.

  3. #3
    tlg
    tlg is offline
    RoadBikeReview Member
    Reputation: tlg's Avatar
    Join Date
    May 2011
    Posts
    16,010
    Quote Originally Posted by jetdog9 View Post
    Are folks using any special caliper or fancy digital tool to measure pad thickness, or just a ruler, or just eyeballing things?
    I've never measured pads. Road or MTB. When they look thin I replace them.

    Interestingly, and I could be totally wrong if I'm measuring poorly, looks like my back pads are a hair thinner than front, totally opposite of what I'd expect.
    That's weird. I've never seen that.
    Perhaps they were dragging?
    Custom Di2 & Garmin/GoPro mounts 2013 SuperSix EVO Hi-MOD Team * 2004 Klein Aura V

  4. #4
    'brifter' is f'ing stupid
    Reputation: cxwrench's Avatar
    Join Date
    Nov 2004
    Posts
    14,920
    Quote Originally Posted by jetdog9 View Post
    Are folks using any special caliper or fancy digital tool to measure pad thickness, or just a ruler, or just eyeballing things?

    When you measure, are you taking the pads out of the brake (seems like pain)? Or just stick a flashlight on them to see better?

    I'm on TRP Spyres... minimum thickness is supposedly 0.8 mm. New pads start around 2 mm, and it looks like I'm down to about 1 mm. Should I just go ahead and change them or squeeze some extra miles?

    Interestingly, and I could be totally wrong if I'm measuring poorly, looks like my back pads are a hair thinner than front, totally opposite of what I'd expect.

    For the record, mixed terrain riding, a few wet rides but not a ton, definitely some steep descents where the brakes are used a lot, took about 700 miles over 15 months to get from 2 mm to 1 mm.
    Eyeball it. If it looks like the friction material is close to being the same thickness as the pad spring replace them. If you use the back brakes much they'll wear more than the fronts because they do so little to slow you down...so you use them more. But they don't do anything (really) so they just wear out. The fronts have much more affect so you can slow more while using them less.
    #promechaniclife

  5. #5
    Neophyte
    Reputation: jetdog9's Avatar
    Join Date
    Jul 2007
    Posts
    1,945
    Thanks, folks

  6. #6
    RoadBikeReview Member
    Reputation:
    Join Date
    Sep 2011
    Posts
    6,406
    Hint: the thickness of most credit cards is about .77-.78 mm thick.

  7. #7
    RoadBikeReview Member
    Reputation: Srode's Avatar
    Join Date
    Aug 2012
    Posts
    3,745
    A feeler gauge next to the pad will give you a good idea if you don't like eyeballing them, or you could measure the pad and backing then just the backing with a caliper and subtract one from the other. I would just eyeball them like everyone else said though.
    Gravel Rocks

    Trek Domane
    Niner RLT9 (Gravel Bike)
    Niner RLT9 RDO
    BH G7 Disc
    Trek Crockett

    "The Spirit of the Party "serves always to distract the public councils and enfeeble the public administration. It agitates the community with ill-founded jealousies and false alarms, kindles the animosity of one part against another, foments occasionally riot and insurrection

  8. #8
    Cleavage Of The Tetons
    Reputation: rideit's Avatar
    Join Date
    Feb 2005
    Posts
    1,727
    Next new product from KMC...Disc Pad Only Calipers!
    $90 shipped, special deal for you!

  9. #9
    RoadBikeReview Member
    Reputation:
    Join Date
    Nov 2002
    Posts
    919

    How to measure disc brake pad thickness

    How about these pads?

    My last two rides were down Mt Diablo. Never expected these pads to wear out so soon. The front brake started to get overly noisy, which clued me in. Probably belongs in CX's hall of shame.

  10. #10
    'brifter' is f'ing stupid
    Reputation: cxwrench's Avatar
    Join Date
    Nov 2004
    Posts
    14,920
    Nah, those are still good. When you can see through 'em you know they're worn out...

    Attached Images Attached Images
    #promechaniclife

  11. #11
    tlg
    tlg is offline
    RoadBikeReview Member
    Reputation: tlg's Avatar
    Join Date
    May 2011
    Posts
    16,010
    Quote Originally Posted by cxwrench View Post
    Nah, those are still good. When you can see through 'em you know they're worn out...
    Those are the new vented pads
    Custom Di2 & Garmin/GoPro mounts 2013 SuperSix EVO Hi-MOD Team * 2004 Klein Aura V

  12. #12
    Russian Troll Farmer
    Reputation: No Time Toulouse's Avatar
    Join Date
    Sep 2016
    Posts
    2,650
    0.8mm is roughly .030". Take a .030 feeler gauge. Engage caliper. Slide feeler between disc and backing plate. If it goes, it's got more than 0.8mm.
    "L'enfer, c'est les autres"

  13. #13
    Neophyte
    Reputation: jetdog9's Avatar
    Join Date
    Jul 2007
    Posts
    1,945
    That makes sense... hadn't thought about a strategy like that.

  14. #14
    Russian Troll Farmer
    Reputation: No Time Toulouse's Avatar
    Join Date
    Sep 2016
    Posts
    2,650
    Quote Originally Posted by jetdog9 View Post
    That makes sense... hadn't thought about a strategy like that.
    It's what every auto mechanic has done since disc brakes were first invented.
    "L'enfer, c'est les autres"

Similar Threads

  1. Replies: 3
    Last Post: 10-29-2019, 02:45 PM
  2. road disc brake pad and rotor life span?
    By deadleg in forum Components, Wrenching
    Replies: 5
    Last Post: 12-07-2018, 09:06 AM
  3. Replies: 27
    Last Post: 04-23-2017, 04:57 PM
  4. Disc brake pad wear
    By Rogus in forum Components, Wrenching
    Replies: 11
    Last Post: 06-29-2015, 12:14 PM
  5. Are there different thickness brake nuts?
    By DIRT BOY in forum Components, Wrenching
    Replies: 4
    Last Post: 08-30-2008, 07:24 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT ROADBIKEREVIEW

VISIT US AT

© Copyright 2020 VerticalScope Inc. All rights reserved.