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Shimano BR-M445 rubbing

sk4tecsk4tec Posts: 11
edited August 2012 in MTB workshop & tech
Hi guys,

I've just bought a Voodoo Bantu. Its a great bike and I really enjoy riding it. I problem since new is that the front brakes always seem to rub. The brakes appear to work strongly. But when not using them over bumps I'll hear a "plink" as monumentality the disc will hit the pad.

The guy at Halfords had a few goes at sorting it out. I've done a bit of Googling (I'm not brave enough to try what's listed in the manual ... 696758.pdf - for aligning the caliper incase I make it even worse).

It was acceptable rubbing only over bumps making a "plink" noise now and again. But then I fell off the bike (slippery wooden bridge and not being used to disc brakes). It was slightly worse. Damage to the bike was a hard knock scratched pedal and bar end. So I thought taking out the rim and re-seating it might make it better - nope. Made it a lot worse. The tech document states:

• The SM-RT53L/M 203/180 mm rotors has a larger diameter and greater

curvature than the 160 mm cross-country rotors. As a result, it may touch the brake pads

The Bantu has 160 at the back which don't touch and 180 at the front which do touch. How can larger discs mean more chance of the pad touching it? From this I can take the that best I can hope for is some hitting on the front wheel.

Anyhow, I guess I need to take it to Halfords for a 3rd time and see what they can do. If again he tries to align it and it works, then it will be (almost) fine till I need to take the wheel off and put it back.

Anyone got any tips\advice?


  • nicklousenicklouse Posts: 50,675 Lives Here
    so have used it yet? have you bedded in the pads?

    and some rubbing is normal.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • sk4tecsk4tec Posts: 11
    I haven't done any specific bedding in process. I've done about 1.5 hours of casual riding. The brakes certainly work sharper than they did when I got it (last Sunday). So I would guess that they are just bedded in.

    Having a look at both the front and rear pads, seems that on both front and rear brakes that one pad pushes more than its opposite pad. I presume that this is 'cos like most car brakes my brakes are single sided piston?

    Is it normal to having to reset the caliper alignment every time you remove the wheel?
  • supersonicsupersonic Posts: 82,708 Lives Here
    Larger radius means that any aberration closer in is multiplied further out. You don't have to reset the pistons every time you remove the wheel, and there are two pistons.

    it is important that the wheel is replaces the same, with he same QR tension. I'd realign the caliper, ride, bed in.
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