How To Measure Brake Disc Wear

james250 · October 3, 2012

Can anyone tell me how I can measure/determine if my brake disc is worn too much and if it needs changing. The pads are all new as it was replaced few months ago but the dealership didnt pick up or comment on the discs. I have already done over 30k miles with my front discs and my brakes have recently started feeling a little weird. So I am wondering if it is time to change the front discs.

If I touch along the surface of the front discs and go to the edge of it, the surface goes in more than the edge, does this indicate that the discs are worn out?

Tango · October 3, 2012

No, but the step does give an indication of how much they have worn down. Lexus no doubt have an advisory figure for minimum disc thickness, but I cannot find it in the Manual.

wendle · October 3, 2012

If you have just had new pads fitted then they will take a while to bed in, they may feel a bit spongy at first, try not to brake hard for the first 500 miles after this time they should be fine.

james250 · October 7, 2012

No, but the step does give an indication of how much they have worn down. Lexus no doubt have an advisory figure for minimum disc thickness, but I cannot find it in the Manual.

I just measured the step from the edge to the disc surface and it is about 2.2mm on one and 2.8mm on the other.