How can I tell whenn the brake...
 

discs need changing on the front?

Is there an easy way of telling?

Thanks

just look at the thickness of the pad and compare it too the back or wait till you here metel grind metel:nono:

He asked about disc's not pads.

The only way of telling when the disc's need changing is to measure the thickness of the disc's. Using a micrometer, I will have a look now as I have seen a thread to a service guide on here somewhere. If I find it I will post another reply. Steve

Sub recommend changing at 22mm, they start off with 24mm, so 1mm wear a side, not much that..

There are the figures

I changed mine not so long ago.
If you cant measure them, just have a visual check and feel the depth of the rim on the outside. If its noticible and the pads dont drop out, i'd chnger them. Mine got so bad without noticing that when i chnged them, i had to pull the whole caliper off...

Generally you can see a lip on the edge of the disc surface, this give a rough indication of wear.

BUT bearing mind, the lip wears down too. So the only way is to get a pair of clipers and meaure the thickness.

MAX amount of wear is 2mm, Original disc thickness is stamped on the inner side of the disc (can't remember thickness of various models offhand - seeing no specific model is stated :nono: ).

YOU MUST check the surface - regardless of wear for other faults like hairline cracking. Such as this: http://www.nataz.pwp.blueyonder.co.uk/archie/brake4.jpg

Also look at the overall surface of the disc as some pads can break up and leave areas of disc unused and corroded, or heavily ridged. If considered excessive grinding/replacement is the only cure.

Thanks for the help.

I took the wheel off today and had a look. I can't seem to find the disc-size though.

There is a small lip on either side of the disc, about 1/2 the thickness of a 1p piece. Is this any use to knowing if they need changing???

Cheers-jim

Sound OK yet to me!

As already posted, disc thickness should be 24mm, 22mm is the min. If the ridge.lip you can see looks about 1mm on each side of the disc, time for some new ones..