Your cna get new textar (on of the major OEM suppliers) for $75-100/pair

My rotors on my MY00 Boxster S are a bit "ripply" which I understand is normal. The thickness measures at .985 inches. That's 25.01 mm. I can't find the spec. Can I keep them, safely, or is it time to replace them? thx

Measure the lip at the edge of the rotor. If it is 1mm or more, it needs replacement.

So the front rotors are worn out at 26mm while the rears are worn out at 24mm.

If that 25.01mm dimension is for the front rotors the rotors are worn past their limit and should be replaced. If that 25.01mm dimension is for the rear rotors you do not have to replace the rotors. New pads can be fitted if they are worn out but it is possible the rotors will wear undersized before the pads wear out.

I have a 2000 Boxster S. Those numbers you state are correct for the front. But for the rear, the minimum thickness given by ATE and by Pelican Parts is 22mm, not 24. Perhaps rotor specs changed after MY2000, but I'm finding that 22mm spec in a number of places. Any further light appreciated. Thanks.

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kentv1
I have a 2000 Boxster S. Those numbers you state are correct for the front. But for the rear, the minimum thickness given by ATE and by Pelican Parts is 22mm, not 24. Perhaps rotor specs changed after MY2000, but I'm finding that 22mm spec in a number of places. Any further light appreciated. Thanks.

Yes, sorry, I goofed in typing in the rear new thickness. It is *24mm*. The 26mm is wrong. Thus with a wear limit of 2mm the rear rotors are worn out at 22mm.

Early on I'd whip out a micrometer and measure the rotor thickness then I got lazy (and I don't remember where I put the micrometer) and for a long time I did what Anker offered. Check the lip around the rotor. If it is 1mm the rotors are worn out. This "works" because regardless of the initial thickness the wear limit is 2mm. (I "use" this technique still when looking at a used car either in person or via pics to judge the condition of the brakes.)

If one is driving the car it is even simpler. Nowadays when the brake wear warning light comes on I just replace both pads and rotors. Then I have 50K or more miles (120K miles from the Turbo's front brakes) of worry free driving, at least worry free from the brakes area.

OK great. Thanks--another question: Which is the left or right on that front rotor? Which way do the slotted swirls go? I'm not seeing any "markings" clarifying that issue.

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kentv1
OK great. Thanks--another question: Which is the left or right on that front rotor? Which way do the slotted swirls go? I'm not seeing any "markings" clarifying that issue.

I don't know. I think I recall (or I imagined it) the rotors were marked/stamped with 'R' or 'L' but I'm not sure about that. Even if I'm right the letter may not be visible when the rotor is installed.

Are you using OE (original equipment) rotors are OEM?

A picture of both the right and left front brake rotors at Pelican Parts shows the slots pointing in different directions.

Here the links to the pics:

Right front:

[www.pelicanparts.com]

Left front:

[www.pelicanparts.com]

Under 99.9% of conditions I doubt it matters

Grant

gee-lenahan-at-gee-mail-dot-com

away from the direction of rotation to aid in expelling any gas that builds up/forms between the brake pad and rotor. The rotation of the rotor combined with the curve of the groove work to move the gas from the inner edge of the pad outward.

I think it makes a difference otherwise why not just machine the grooves straight?

For rotors that have internal vents the venting works by centrigual force. Air coming into the wheel well and encountering the wheel and the brake rotor is encouraged to flow from the wheel hub out through the inside of the brake rotor helping to keep the rotor cooler.

By installing the rotor on the wrong side this air flow is compromised maybe to the point there is no air flow through the internal rotor vents. For street use the less effiicient cooling probably won't impact braking effectiveness to any noticeable degree. It might result in higher peak temperatures of the rotor and this could lead to shorter brake rotor/pad life. And in those situations when the car is brought to a stop with hot brakes subject the rest of the immediate brake hardware -- mainly I'm speaking of the caliper and its internals including fluid -- to more heat which has to have some effect on the life of these components. So in this case like the grooves I'd install the brake rotor for the side it is marked.

Even for strictly street use I see no reason to tempt fate, experiment, with installing the brake rotors the wrong way. For a tracked car any owner who installs the brakes marked 'R' and 'L' on the wrong side should not be allowed on the track.

I just think it makes a very small difference for most applications.

Grant

gee-lenahan-at-gee-mail-dot-com

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grant
I just think it makes a very small difference for most applications.

Matters enough that the rotor makers mark the rotors R or L.

Here's one"
[www.autohausaz.com]

Sebro has a good reputation as does Zimmerman. I wish I could replace a front rotor on ours for $100.

Are you on the original brake pads, i.e. new when the rotors were new?
If so I think you can wait for the brake wear light to come on before replacing both.

i use them all the time. Why not?

[www.pelicanparts.com]

I also find good deals on Amazon (yep). brembo, meyle, zimmerman also good.

The wear spec (bentley) is 22.6mm front, 18.6. for some reason, they do not differentiate between base and S.

Are the rotors the same thickness? i Don't think so... concerns me.

As i recall it was basically a 2mm wear limit, best measured relative to the lip.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Just fyi, my rotors were badly worn and my warning light came on. I used the cheaper ATE rotors and they seem great. I installed the fronts correctly, using the directional recommendation. I had 86,000 miles. I used a Stanley sliding vice clamp with the plastic covers to compress the pistons. That worked great. Porsche must deliberately have designed the brakes so folks like me could do this. It was like putting a little Lego model together, but possibly not as hard.