I bought replacement pads for my Deore A-M615 brakes. They installed just fine. But after cleaning the old pads, I saw that they are G01S, while the new ones are B01S.

G01S, the original: G01S

B01S, which I bought by mistake: B01S

The "incorrect" B01S have just fitted fine, and seem to do their work equally good. Should I now:

  • ride as usual?
  • buy the correct pads, ride carefully before that?
  • buy the correct pads, not ride with the wrong ones even to the LBS?
  • 4
    It's no problem at all. These seem to both be resin, it would be fine even if you were switching to/from sintered pads
    – BSO rider
    Nov 5, 2015 at 0:33
  • Commenting on my own question: the "wrong" B01S pads have worked in various conditions just fine. I do not see a reason to replace them. Nov 13, 2015 at 11:21

3 Answers 3


The G01S pads are slightly wider, and slightly shorter, than the B01S which you replaced them with. If you compare backing plates carefully you will see the difference. I know this because I thought they were all the same but a genuine Shimano bleed block wouldn't fit in a BR-M395 caliper that has B01S as the specified pad. You may need a digital caliper to measure the difference.

Thus you can stick the smaller B01S into a G01S hole, but not the other way around... A G01S will not fit in an Acera BR-M395 caliper (or a BR-M315, BR-M355, BR-M396, or Alivio BR-M445, or others that have th B01S as OE). I wouldn't use the B01S pad in your application because it'll be wiggly in your M615 brakes - The loads from braking are transferred to the beefy sides of your caliper, the through the caliper to the frame. Wiggly pads will "wear out" your alloy caliper, making the hole bigger, and applying a torque to the split-pin that holds the pads into the caliper.

It probably isn't dangerous our anything, at least not over the life of one set of pads, but it will chew up your calipers some, which is more expensive than buying the right pads.

  • Welcome to Bicycles @Steve. You've made a good start! Even so, it will be worthwhile to take the tour to make best use of the site. Good to see you here. Looking forward to more from you
    – andy256
    Nov 16, 2016 at 11:45

If they work, use them. When I've been unable to find the right pads while touring I managed to find some that would go into the calipers and initially I planned to just ride to the next bike shop. But they worked as well as the originals so I kept them until they wore out.

The key factors:

  1. material compatible with your brakes (resin/sintered)
  2. they fit properly (no extra wiggling, test by pulling the brake lever on then trying to roll the bike forward and backward. If there's slop in the brakes you may well have problems.
  3. they lock in place using the proper fasteners. I've heard of people using cable ties to hold "wrong" pads in place. That kinda works in an emergency. Be very careful.

But since your "wrong" pads seem to fit properly, I think you'll be fine.


Seems that the answers are all yes, no and maybe at the same time


Summarises to "they're close but not the same, theres a different profile on the two models of pad."

You're unlikely to get a refund, so if they work for you then all good. Do remember to get the right ones next time. Given they're only 6 euros you could just buy them.... pads are cheaper than rotors.

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