Shimanxo SLX m7120 brakes not working on new bike.. advice please


Winford

Member
Oct 29, 2024
92
113
auburn ca
Thanks for everyone's help.
depending on how much you ride and what kind of elevation your dropping, I go through pads every 2 months tops. I was using shimano NO3s and just switched to bucklos ceramic. So far they are awesome and thicker pads means they last longer. If your bike is set up right, you know when the pads are low, because you will get drag on the tire. When the caliper pistons are out to far, they do not retract back in correctly causing drag. So it snot often I ever get pads down to metal. As far as ROTORS. You can use the 220 on rear, just save your magnets from the 203s and drill mounting holes in the 220. Works great and looks legit like a factory install. Now the cats meow is what im doing and using Sram 220 h2 rotors because they are 2m wide and last longer then the shimano 1.8m rotors. Them combines with bucklos thicker pads, im getting the best stopping power and bang for your buck money wise. I ride almost 30 miles a day of single track and drop 4000' almost every day. Last year I dropped 345,000' in elevation. So getting pretty good at brakes on a shimano set up. Your original pads were crap, they looked like oil soaked and or glazed.
 

Winford

Member
Oct 29, 2024
92
113
auburn ca
Correct me if I'm wrong, but the ability to dissipate heat is by contrast non-linear.
So you think a 160 brake and 220 offer the same performance? or do you recognize there is a difference, and f so how much. Well it is common knowledge 203 to 220 is a 10% difference
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
3,074
7,474
UK
I am curious how air in the system causes uneven pad wear. Air bubbles behind 2 of the pistons perhaps?
That would be a good guess. Shimano brakes IME come with more free stroke than SRAM, there's ways to reduce it but if you're switching from one to the other, it's very noticeable. They also tend to have a more on/off feel than other brands too. Air trapped in the calipers, misalignment, dirt causing pistons to stick are all things that can compromise brakes, you have to work through the issue but that guy's pads were clearly only partly contcting the disc.

As it goes, I've just had the same thing with my car. New pads & discs on the back & didn't feel like they'd bedded in very well, so another look & spotted that the clips on the rear of the inner pad which are designed to secure onto a lip on the piston had become dislodged & only about 20% of the pad was working. Different wheels, same principles.

IMG-20250222-WA0003.jpg
IMG-20250222-WA0004.jpg
 

irie

E*POWAH Elite World Champion
Subscriber
May 2, 2022
3,248
3,385
Chichester, W.Sussex, UK
So you think a 160 brake and 220 offer the same performance? or do you recognize there is a difference, and f so how much. Well it is common knowledge 203 to 220 is a 10% difference
I neither said nor implied that "a 160 brake and 220 offer the same performance". :rolleyes:

What I said was:

irie said:
Correct me if I'm wrong, but the ability to dissipate heat is by contrast non-linear.

As you can see, I specifically referenced heat dissipation.

hth
 
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