How can you tell if they really need replacing? I need new pads all the way around, and one mechanics says the rotors are at the end of their life, and another who says that they are fine. There is no pulsating when braking, and no cracks anywhere on them either. The outside edge has a little "lip" on it maybe 1/16". Thanks.

 

Factory specs call for no more than a 7mm crack between vent holes. If they are 7 or better or if they cascade over the edge of the rotor then they need replacing. Its not recommended that you "turn" them, although a very light pass that doesn't take off anything but the tallest high spots wouldn't be bad. Just don't have them ground down like a normal "turning"

 

+1 very light turn, check spec for thickness before and after turning. I had mine done last year and they are working great. No track use however.

 

The rotors also have a minimum thickness. It is typically marked on the rotor hat somewhere. You should measure the rotor and compare that with the minimum. You can use a micrometer to measure it.

If you have 1/16" lip you do have some wear...

 

No cracks and a 1/16"--unless you feel something wrong when braking, you're absolutely fine. Check 'em when you next change the pads or bleed the brakes.

Turning not recommended, and at the price that you can buy new ones from Sunset, why bother anyway.

 

If you decide to ditch the front ones, let me know.

 

I just went through this. I was told that if there is a discernable lip around the edge, they are ready to be replaced. Mine did, plus when I took it in the shop told me they discs were not OEM. So I had all 4 replaced, with new OEM pads at the same time. Much better!

 

I just did too -- measured my fronts for thickness, and they're right at 30mm, the wear limit. So if anyone has a pair of front rotors for sale that are new/barely used, let me know. Otherwise I'll have to commit the sin of paying retail...

 

Thanks for comments. I appreciate them. Gonna pull the wheel and take some precise measurements!!!!