Backwards brake noise

[Motormike]

I park my Kat front-forward in my garage, which is slightly uphill from the driveway. When I back it out, I have to roll it down the hill a bit (maybe 20') until it's flat again and then I can start it and let it warm up.

As I'm backing up, I use a little front brake to keep it from rolling too fast, and I can hear a little metal-on-metal grinding noise. Is this normal? Am I doing any damage? The brake pads are all fine, and there's no noise during forward motion, just backward.

Thanks!
MM

[The CyberPoet]

Metal-on-metal noise isn't uncommon when you first start moving a bike (there are metal flakes in the pad materials), and as long as you are sure there isn't any sand or clay-dust trapped between the pads and the rotors, that's fine.

BUT it could also be sand trapped in there; cleaning your rotors and pads with spray brake cleaner every month (or far more often if you live in a particularly dusty place, such as on a dirt road) is wise.

KNOW THIS:
In a perfect environment, the rotors would never wear, because the pads place a light layer on them and then friction against that layer. All grooving and wear on the rotors comes from other hard stuff getting stuck between the pads & rotor and gouging it out.

Cheers,
=-= The CyberPoet

[Motormike]

I notice the noise only when rolling backwards, not forwards, so it doesn't sound like sand in the brake pads. Could it be that the pads get some kind of directional "feathering" or "cupping" that would make noise when the normal direction is reversed? Or could there be something on the Kat that's not built for having brakes applied while moving backwards and is causing the brake components to shift and contact differently?

That said, I'll have to take a good look at the pads and rotors and see if anything looks like it's wearing oddly.

Thanks,
MM

[GregS]

Several bikes I've owned did this and it usually turned out to be dust or road dirt building up on the leading edge of the pads. I just use the garden hose on the brake caliper, preferably while rotating the wheel backwards, to clean out the brake. After any cleaning of brakes please note you may have reduced braking ability for the first couple applications.

[The CyberPoet]

Low-pitched squeal is usually the pad edge at the rotor; high-pitched is often the pad vibrating on the carrier pins. Since it's only happening in reverse, I wouldn't sweat it at all, but if you want to, you can bevel the trailing edge with a rasp or file.

Cheers,
=-= The CyberPoet