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Old 09-11-2014, 10:35 AM   #1
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Rotor wear Boxster S brakes

Here are my rotor thickness measurements:

LF: 1>27.38mm 2>27.35mm 3>27.44mm limit:26mm?

LR: 1>23.63mm 2>23.65mm 3>23.66mm limit:22mm?

RF: 1>27.48mm 2>27.42mm 3>27.25mm limit:26mm?

RR: 1>23.65mm 2>23.56mm 3>23.54mm limit:22mm?

How much longer can I expect these rotors to be within spec.? Are my limits correct? The car is not a dedicated track car; won't be anytime soon; hard braking on street. Generally it looks like I am playing with 1.5mm and that is it! This could only be half life but not sure

I ask as I am all jacked up and wanting to pull the rotors off and clean them up; paint as they are throwing rust every where

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Old 09-11-2014, 12:00 PM   #2
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Boxster S:
front- 28mm new, 26mm limit
rear - 24mm new, 22mm limit

To calculate how much wear you have left;

Step 1. Subtract the existing thickness from the new thickness
Step 2. Divide the number of miles since the rotors were installed by Step 1.
Step 3. Subtract the min thickness from the actual thickness of the rotor.
Step 4. Multiply Step 2 by the remaining thickness of the rotor (until it reaches min thickness).

This will give you an approximation of the number of miles until you reach the min thickness. This assumes that rotor wear is linear and that you continue to drive the same.

Example: LF

The average of the three measurements is 27.39mm
Assume 5,000 miles since rotors were new (USE THE ACTUAL MILES!! This is just my assumption for this example.)

Step 1: 28.00 - 27.39 = 0.61mm rotor wear
Step 2: 5,000 miles/0.61 = 8,197 miles per mm of rotor wear
Step 3: 27.39 - 26.00 = 1.39mm remaining rotor wear
Step 4: 8,197 x 1.39 = 11,394 miles until the rotors reach 26mm min thickness.
1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
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Last edited by thstone; 09-11-2014 at 12:04 PM.
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Old 09-11-2014, 04:12 PM   #3
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Thanks Tom! You did it all for me!! I wasn't sure about my limits so I was guessing. I was missing the new dimension as well

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