Front Brake Discs

When braking I get a slight judder on the front brakes when at high speed,
and as the speed decreases the judder gets more pronounced.

Is there a simple way of checking my front discs to make sure they are not
warped? I've looked at them and can't notice anything obvious.

Thanks in advance.

 

Sounds very much like a warped disc or two to me.

Visually, there's not much difference between a warped disc and a flat
disc. Quick and dirty check: get the front wheel off the deck and
hold something like a steel ruler against the brake caliper and /just/
touching the disc, then rotate the wheel. Warpedness should become
obvious if it exists.

Otherwise, remove disc(s) from wheel and lay on a known flat surface -
a piece of glass is good, a surface table better. Assess warpage by
slipping a thin (or thicker ;-)) feeler blade between disc and glass.

A cruder method would be to lay the wheel down flat (having removed it
from your bike), ensuring that the disc beneath is protected from
damage and hold a steel ruler across the upper disc. Try to slide a
feller blade between ruler and disc, moving the ruler around the disc
surface to check it all round.

If your discs prove to be flat, I'd suggest checking pad condition and
security, tightness of caliper bolts and freedom of movement of brake
pistons. Failing all that, you can get into head bearings etc etc ...