Straightening a brake disc?

[mat777]

I have a front wheel with attached brake disc on ebay at the minute for £12.50. with 12 people watching it so I'm pretty sure I'll get a bid. It is advertised as disc and wheel in perfect condition: running straight and true.

Unfortunately a ham-fisted parent has moved it in the garage from where I put it, and thrown it in the top of a trailer of stuff. As a result, the brake disc now has a bend in it so that about 1/5 of the circumference bows in by 3mm when the wheel is spun.

I have taken the disc off and tried to hammer it straight on a flat surface but it just springs back into its bent shape.

Anyone got any ideas?

Thanks,

Matt

[Rolls]

adjustable spanner - adjust onto the disc, and strighten a bit at a time - in the bike to check its true. job jobbed.

[Watchman]

Not sure I'd be keen to sell it now. Doesn't take much for a brake to be off.

[Rolls]

It'll be fine! :-)
Was having to straighten brakes on my yeti every day in the alps a couple of years back after tting them on stuff...

If you really want, you can buy the park too to straighten it.. but a spanner is cheaper

[mat777]

Thanks for the hints chaps! Myself and a friend stuck it in an upside down bike and fiddled with the caliper to see where it was catching, we've managed to straighten it enough so that it is invisible to the naked eye and just about clears the normal pad gap in a disc caliper. I've edited to the ebay listing as well to say "true when spun in front of eye" so that should cover my back.

[cheeky_chops]

have you tried cycling with it? Mine fell off the roof rack (dont ask ) on the way to cannock - the tethers kept it on but it landed on the front roof bar right on the disc. I just went into the shop and bought another as even though it seemed straight i could feel it "pulsing" and grabbing as i cycled around the carpark