Wondering if anybody else has found it really difficult to get Deore 4 pots bedded in on 180mm rotors. I’m wondering if part of the problem is the bike has been sat too long in the build/delivery process before getting to me.
Ive tried cleaning rotors and starting again. I might try a bleed as they feel spongey but this wouldn’t normally impact the power presumably?
Just wondering if others have found it straightforward or tricky?
I fitted a 4 pot SLX caliper to my bike last year and it fell pretty poor at first, in the bike stand and usual up the drive test ride. I went a longer ride and it bedded in properly and was fine. Great brake now
what makes you think they're not bedded in well? is it a lack of power?
I don't know but I wonder if the pads are resin in the deore brakes?? in my experience they don't feel brilliant.
how have you tried to bed the pads in? there was a YouTube vid of a DH riders mechanic bleeding brakes and bedding in pads. all he did was wet the pads and rub them together, and kept rinsing until the water ran clear from them. I've been doing that since I saw it and it works well for me (well using uberbike race matrix pads)
edit I've got SLX 4 pot with 203,180 and really dont want for extra power!!
Rub some gritty, grindy mud over the discs and then do some hard stops. That’s what I usually do with any brakes.
Get em gritty, get em hot, then wash with water
I tend to lightly sand brand new pads if they have a 'glaze'
Do what Marshy does. It works everytime.
Is this on a brand new bike? Spongy brakes doesn’t sound good. I’d take it back to where you bought it...
You need to ride it and get some heat into them! The resin pads can feel a touch spongy, but will bed in reasonably quickly. If they're fitted with sintered as they were on my new eBike, they can take longer than most brakes to bed in for sure, but a BIG hill and the opportunity to get them up to temperature will help.
I had a set of front and rear Deore 4-pots when they first came out, from Rose bikes. One brake was perfect the other spongy, wouldn't brake properly and honked - all the signs of a leaky calliper. Checked and it was damp with fluid leaking round the seals. Sent it back. Annoyingly they refunded me rather than sending a replacement. But worth checking it's not leaky.
Thanks all - lots of things to play with and try.
The reason it feels odd is I recently fitted some 2 piston XT brakes and they were so no-nonsense that it seems weird these are lacking in bite power despite following a fairly similar bedding in process. I just can’t get them to come to life.
I’m going to give the brakes a bleed, try different pads, clean up the rotors and inspect the calliper.
Out of interest are they resin or metal? My bike has 4 pot Deore and TBH I have no experience of anything else as it's my first bike with discs but I did 20 or so stops from about 10MPH when I first got the bike and have had no problems since. Coincidentally I put a new set of Shimano pads in yesterday (on the same rotors) and they felt perfect from the word go. I did a similar bedding in but it didn't change much. Mine are resin D03S pads.
bedding in is 3 things. conforming the pads to the disc, depositing a thin layer of pad material on the disc, curing the pad with heat and pressure
the way to do it is with multiple hard stops
Some people their riding style means that they do this in normal riding, some folk need to do it deliberately
All the mud gravel and water nonsense is cleaning contaminated or glazed pads. it is not bedding in
It is possible to cold glaze pads from never getting them hot enough - they then need abrasives to break up the glaze
The tiny little screw in the lever could make all the difference. I have new MT420 brakes and the front bedded in fast, but I couldn't seem to get the rear to lockup. The lever felt weird. Thought something had gone wrong. Stuck an allen key in and screwed the bolt in a bit at a time and suddenly all was good.
Ive never used Shimano hydraulics before. Always had Hope and Hayes. This adjustment produced effects that were frankly wierd compared to what I've used before.
A good shout. In case anybody else reads this post in future I:
- sanded the pads
- cleaned the rotors
- adjusted the levers a bit
It took a good 20 or more pulls on a steepish hill and then suddenly the pads began to bed. They squealed like pigs for ages before bedding down. They now seem ok in the car park but yet to ride off-road.
My SLX came with contaminated pads. They felt solid, but with no chemical grip. Had to go with new pads.