Juddering discs... cause? .. fix?

mysterious_rider · World Chat Champion Joined: 11 Sep 2010 Karma :

Well my front brakes judder. I checked them out and on the outer edge is a slight lip. If I removed this lip with a grinder would this stop the judder do you think?

Utter bodge I know. But the discs themselves are still quite thick. Just seems a shame to have to fork out £200 for a new set.

andym · World Chat Champion Joined: 16 Nov 2010 Karma :

spin the wheel and make sure they aren't warped, the outer lip shouldn't really affect the brakes tbh (unless you've fitted new pads)

Nick_Giles · Could Be A Chat Bot Joined: 01 Jan 2012 Karma :

Slightly off topic I know. But while we are on the subject of disks with 'lips' on them does this affect an MOT test.?

Nick.
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Pete. · Super Spammer Joined: 22 Aug 2006 Karma :

Only if the disc is below minimum thickness, which is usually stamped on it.

The lip is unlikely to be the cause of juddering. A warped disc or carrier is more likely or oil contamination especially if the fork seals have been leaking. I wouldn't recommend grinding on the disc, you could actually induce warp with local heating.
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bodger · Nova Slayer Joined: 18 Apr 2012 Karma :

Forget the lip on disc if its only slight.The suggestion about oil contamination seems more likely.
Maybe from the brake caliper or as suggested, running down the fork leg onto disc.
Also check headstock bearings for looseness this could make a slight shake feel worse.

MarJay · But it's British! Joined: 15 Sep 2003 Karma :

Robby had a bike which had 'warped' discs, and it turned out that it was corrosion behind the mounting points. He removed the discs, cleaned the mating surface of the wheel, and refitted them and they were fine.

I've also seen it where the brake pads have rusted to the disc leaving a little deposit on the surface of the disc which gives the same symptoms as a warped disc. Sadly the only way to sort this is to have it skimmed, but at least you won't need to take too much off. if the disc is below the minimum thickness it will need replacing anyway.
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mysterious_rider · World Chat Champion Joined: 11 Sep 2010 Karma :

P.addy · Red Rocket Joined: 14 Feb 2008 Karma :