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Had a slight pulsing of the brake lever for a while, which gradually got more pronounced; cleaned & spun the bobbins - some improvement. Had a closer look - one piston appeared to be sticking - quick clean, & much better.

Generally I ride fairly gently, mainly relying on gears & engine braking. However, on Sunday's pootle, the wide open spaces of the A5 had their usual effect on me. I found myself needing to brake quite hard approaching roundabouts etc. from 90-ish. Each time, there was substantial juddering of the front end; easing off, & re-applying pressure steadily, resulted in less judder, but it was still more than noticeable. Was somewhat disturbed by this.

Pads seem ok. Discs don't look obviously warped.

Thoughts, please?

it's hard to tell if the disk's are warped by eye,if you've cleaned the bobbins and sure there ok i would say your disk or disk's are warped, you could try getting the wheel off the floor and spinning the wheel and just touching the lever with one brake line clamped at a time you'll know which side is giving you the problem. if they are warped theres a guy local to me that repairs warped disk's and fits new bobbins.
hope that helps.

Pad material build-up on the discs could be a cause. Have you changed pads recently? I bead blasted my discs not so long back and the shuddering dissapeared completley but it came back within a 100miles. This all happened after i changed the pads. I wish i new which pads they were so i don't buy shit again (i thinkl they were EBC). Next time i am going for a decent set of pads.

I get a little juddering from time to time. Usually giving the brakes a bit of a work out clears it for a while.

Were the pads bedded in correctly? ..... this is a fairly lengthy read but it is well worth reading ..... http://www.stoptech.com/tech_info/wp_wa ... disk.shtml

MartDude wrote:
Thoughts, please?

Sounds like warped / sticking discs, but might also be worth checking head bearings / wheel bearings just in case

I second that.... get the front end off the ground and check for slack in the bearings.

Sorted! I think . . .

Got the discs off, and went through the bobbin tab washer bending routine, as per this (follow the links ) http://www.apriliaforum.com/forums/show ... rotor+tabs , and using lots of brake cleaner & spinning the bobbins.

On the short ride home from the workshop - no pulsing lever, & no juddering braking from 45 mph.

Will give them a more thorough test tomorrow

Thanks for your input, peeps.

Yup, it seems to have worked.

No juddering braking hard from 90-ish

Excellent stuff; always a good feeling when a Plan works out...