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Old 06-15-2008, 08:35 AM   #10
Lil bastard
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Quote:
Originally Posted by 2000SoCalBoxsterS
I have 39,759 miles on my Boxster and my pads look less than half way worn. I measured my left front rotor and got 26.49mm and decided to post to find out what this means for me.

For the Boxster S new rotor thickness is 28mm Front and 24mm Rear. The wear limit is 26mm Front and 22mm Rear. So you've got 2mm from new to wear limit?

Then there is a machining limit which is about 0.6mm thinner than the wear limit for the Non-S Boxster. Does anyone know what it is for the S rotor?

What exactly is the "wear limit" ? It's not the point at which you need your rotor's cut is it? Can't be after only 2mm ?

Is the "machining limit" the point where you have to buy new rotors?

My Bentley's shows the machining limit for the Non-S Boxster rotors at 22mm Front and 18mm Rear. They don't provide this data for the S model.

Am I only 0.49mm from having to turn my rotors? How long will that 0.49 last me?

Boxster 'S' data is 28mm (Fr), 24mm (Rr) w/ minimum thickness (wear Limit) of 26mm and 24mm respectively. Yes, you have 2mm new-to-wear limit. 2mm of 'gray' iron takes quite a while to wear away, and don't forget, the pads are wearing away at a rate of 3:1.

The wear limit is the point where your rotors should be replaced. This keeps the brakes operating at maximum and properly. Wear too thin and not only do you risk having a rotor fail, but you over-extend the caliper pistons, allowing them to corrode and tear the seals.

The machining limit is the absolute limit in terms of maintaining the rotor's integrity - you do not ever want to use this limit - replace at the wear limit. The Machining limit is provided to guide the operator in turning the rotor for lateral runout.

How long will .49mm last? Depends on your driving habits and type of brake pads used. But, do the math... you started at 28mm and 40k mi. later, you're down to 26.49mm. That works out to 0.0000377mm/mi. and given that, about 13k mi. from now you'll have worn away the remaining .49mm.
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