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How can I tell when my hydraulic disc pads need to be changed?

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How can I tell when my hydraulic disc pads need to be changed?

Old 08-09-22, 01:10 PM
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Route 66
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How can I tell when my hydraulic disc pads need to be changed?

My Spot ACME bike has Sram Level hydraulic brakes on it and I'm wondering how I will know when it's time to swap out the disc pads for new ones. I do have a set of calipers and a micrometer and can measure both the mounting plate's thickness and the pad material's thickness if that happens to be the first step.

Any input will be helpful.
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Old 08-09-22, 01:21 PM
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I don't have the same brakes, but ...

I asked the same question a cpl years ago but never really got a definitive answer, other than don't wait to hear scraping metal sounds

I've changed mine twice since then. neither time did they look excessively worn

for me, I'll do it if the brake is making noise or there's a noticeable loss of performance, like from some kind of contamination - even after checking wheel alignment & cleaning the rotor

it was interesting to see that the inner & outer pads wear differently

old vs new

honestly don't remember what exactly these pics are that I took



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Old 08-09-22, 01:39 PM
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Originally Posted by Route 66 View Post
My Spot ACME bike has Sram Level hydraulic brakes on it and I'm wondering how I will know when it's time to swap out the disc pads for new ones. I do have a set of calipers and a micrometer and can measure both the mounting plate's thickness and the pad material's thickness if that happens to be the first step.
Yep -- pull the pads out and measure them with calipers. The Level manual says "When the thickness of the backing plate and pad material is 3 mm or less, they are worn and need to be replaced with new disc brake pads."

https://www.sram.com/globalassets/do...d-shifters.pdf
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Old 08-09-22, 02:53 PM
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I use 1mm pad thickness a a replacement point on bikes and a trike, I inspect often.
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Old 08-09-22, 05:09 PM
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Thanks for all the helpful answers guys.

I have a follow up question too: what's the best way to clean the rotors before I install the new pads?
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Old 08-10-22, 08:27 AM
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I use isopropyl alcohol because I am retired and so have the time to do it often before they get bad and it does not leave anything on the surfaces. I also don't get anywhere near my rotors with a spray of any kind. A tiny bit of mist of a chain lube or general lube of any kind can give you a mess very quickly.
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Old 08-10-22, 08:56 AM
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Originally Posted by easyupbug View Post
I use isopropyl alcohol because I am retired and so have the time to do it often before they get bad and it does not leave anything on the surfaces. I also don't get anywhere near my rotors with a spray of any kind. A tiny bit of mist of a chain lube or general lube of any kind can give you a mess very quickly.
Thanks for the reply. Are you able to clean them with the alcohol while they're still on the bike, or do the rotors have to be removed from the wheels first?
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Old 08-10-22, 09:00 AM
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Originally Posted by Rolla View Post
Yep -- pull the pads out and measure them with calipers. The Level manual says "When the thickness of the backing plate and pad material is 3 mm or less, they are worn and need to be replaced with new disc brake pads."
ha! that must be why I also have these 2 pics of old pads prior to replacement




wish I could find that thread of mine from a cpl years ago ... found it!

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Old 08-10-22, 09:02 AM
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We use steel wool first and follow up with alcohol leaving the rotors on the hub for easier holding of them and less time (but we do check the mounting hardware just in case) Andy
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