I'm rigging up a bastard big brake upgrade using various different components.
Everything is looking ok except that the pad area is slightly larger than the friction area of the disc im using. This means that a lip will form on
the pad as it wears.
How bad is that? Because to me it doesn't sound good!
One couldn't trim brake pads could one??
dunno but mr whippy will know - but how is that different in having a slightly smaller pad so the lip develops on the disc?
I cannot see how the lip on the pad would ever affect braking - let's say the disc got really hot and expanded to a bigger diameter - this would
rub agains the lip so it will wear it enough so that you'll never get a problem with the pads not pressing against the disc.
anyway let's see what the collective brain that is lcb have to say.
oh, re trimmingthe pads - dunno about that but if there was an accident and the pads were examined, it would not do you any favours to have
lateredthem from the manufacturers design.
[Edited on 8/4/09 by 02GF74]
I agree that trimming pads is dodgy to say the least, but as devils advocate is it not the same as using manufacturers parts in non intended
applications like locosts
quote:
Originally posted by 02GF74
oh, re trimmingthe pads - dunno about that but if there was an accident and the pads were examined, it would not do you any favours to have lateredthem from the manufacturers design.
[Edited on 8/4/09 by 02GF74]
I'd just go at the lip with a file occasionally, bring the pads back to flat.
Worth mentioning I used to do this (and other sins) fairly regularly on mountain bike disc brakes, never had pads fall apart on me.
[Edited on 8/4/09 by Staple balls]
As with 02GF74 I'm a little wary about the idea of trimming the pads. As long as the lip formed doesn't foul anything I'd leave it on.
The classic problem would be that if worn the lip on the pad would stop the worn part contacting with the brake disc
I would say, and in fact I do say, that having the pads outside the swept area of the disc would not be a problem at all. Providing that it's only a little bit and not 50% of the pad was hanging off!!
without measuring i would say it about 2% max
I'd say not a problem at all - I tried to fit some Hi-spec callipers on to 285mm disc's , and the piston's were off the edge of the
disc by about 30% - and they couldnt see the problem 
Neddless to say they went back for a refund......
I've run into pad wear like this on customer cars before. Usually it's a bent pin, or the wrong pads installed.
You will not notice any braking issues from this while driving.
I do wonder though if the pads I see hanging over a lot started out as just a little, then as the pads wore a tapered edge they slowly pushed
further and further out bending the caliper pins.
I would just chamfer the edges on the grinder so they don't hang over. There is no harm in this, and it ends any concerns.
Cheers.
Can't you find any pads that are a little smaller or discs a little bigger?
I'm guessing it's a no but should be worth looking so as not to have any problems. I'd see it being an mot fail if they find the pad
hanging over the disc