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Old 06-12-2008, 09:31 AM   #1
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Question Boxster Brake Rotors Mileage Life???

Has anybody had experience with Brake rotors such as OEM or Aftermarket replacements, turning rotors, or life expectancy?

My rotors (1998 w/60Kmiles) have a dime thick outer edge developing on the outer portion of the disc where the pad doesn't make contact. The surface is generally smooth.

How long have you had your rotors? Mileage, etc.??
Mileage on your rotor life please.

I'll start: 1998 w/60K Miles.

Thanks.

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Old 06-12-2008, 09:55 AM   #2
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How long your rotors last will depend on a few things; how often and hard are you on the brakes (an expressway only car will go a lot more miles than an urban stop & go car will), what type pads are you using?, etc.

To check, you need a micrometer. Rotor Wear Limit is 22.6mm (Fr) and 18.6mm (Rr). The Rotor Machining Limit is 22.0mm (Fr) and 18mm (Rr).

If you have a ridge built-up on the rotor, this can be machined off and the pad roughed up (smooth isn't better) - usually about $15/rotor

You should also check for rotor lateral runout (warpage). This spec is 0.03mm. There is also a Peak-to-Valley surface roughness spec after machining of 0.006mm.
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Old 06-12-2008, 03:00 PM   #3
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I have a 1997 with 67,000 miles and my front rotors are the originals and still within specs. I am on my second set of front pads - the first set being when the car was new.

Still have the original rear rotors and pads.

Measure them and see what you got. Depends on how you drive.

Last edited by Tool Pants; 06-12-2008 at 04:03 PM.
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Old 06-12-2008, 05:27 PM   #4
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Rule of thumb with the Boxster is that you get 2 sets of pads to a rotor. So, if you're going to your 3rd set of pads, you probably need rotors too.
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Old 06-13-2008, 05:04 PM   #5
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Thank you very much guys.....UPDATE

I appreciate your help.

I decided to go with new OEM rotors although originals had 60k miles.

Maybe I can recuperate some money by selling these.

Thanks,

Junior
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Old 06-13-2008, 05:27 PM   #6
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If I were going to the trouble of installing brake discs or paying to have them installed, I'd be replacing my worn ones with brand new. I don't think worn Porsche rotors that have been turned have much resale value. A scrap yard will pay you for the raw steel value.
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Old 06-13-2008, 10:01 PM   #7
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have a 2001 boxster S, has about 65,000 miles on it. got it used at about 48,000 miles. previous owner didn't take good care of the brake pads, so it started to wear on the rotors too. so had to change all the brake pads and rotors at 60,000 miles or so.

I definitelty will keep a closer eye on the brake pads. OEM rotors for the "S" ain't cheap
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Old 06-14-2008, 07:00 PM   #8
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I changed my fronts @ 79k. I have had car for 14 months so I don't know the history. Rears are due also. Probably in a week or 2.
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Old 06-15-2008, 04:35 AM   #9
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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?
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Old 06-15-2008, 08:35 AM   #10
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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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Old 06-15-2008, 09:09 AM   #11
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Thank you Lil Bastard, you're right, all I had to do was the math.

I was just missing a piece of information for my equation that you now gave me. That 2mm of metal off the rotor is all you get.

Since I moved back to New York from California (back in 2006) I only put on about 2,000 miles a year. At that rate I won't have to buy new rotors for 6 years! But since my new found interest in DE and AutoX I guess it will be more like 1 year or two summers.

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Last edited by 2000SoCalBoxsterS; 06-15-2008 at 09:15 AM.
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