Nobody

Those little hairline cracks in rotors. I found out that they sometimes turn into big cracks recently! Is it a good idea to turn a spiderweb cracked rotor or just leave it alone?

While I'm at it--I've been trying to dial in RA1 tire pressure for awhile.... Everyone seems to recommend running at or near 40 hot, but I seem to get better results in the low 30s hot. Am I crazy?

And now that I'm running the NT01 rears (and love 'em) I'm totally as to what to shoot for.

mikegarrison

I recently took a couple sets of rotors to a machinist with lots of autosports experience. He was willing to turn one of the sets, but he said the heatchecking was too bad on the other one and it wasn't worth machining.

I haven't run the set he turned yet, so no report.

Raymund

[QUOTE=Nobody,Jun 13 2006, 04:35 PM] While I'm at it--I've been trying to dial in RA1 tire pressure for awhile.... Everyone seems to recommend running at or near 40 hot, but I seem to get better results in the low 30s hot.

rlaifatt

Ray, I'd be concerned about turning a used rotor for tracking. If they already show signs of stress like spider crack lines, it seems that removing material will only make them weaker. If the surface is irregular (like wear grooves, deposits etc.), I find that a new set of pads (Hawks anyway) cleans them up, or I simply replace them.

mikegarrison

For $25/per I was willing to try them out. I had them done by a professional machinist, not the 19-yr-old kid at the local tire shop. I don't expect them to be as good as new, but if they are even 1/2 as good as new it was worth the money.

If they fail disasterously and kill me, it wasn't worth the money.

We'll see....

Raymund

fwiw, I've had rotors with decent amount of spider cracks (some 1" in length)turned. They're actually on my car right now with over five track events. I always bring an extra set just in case they go.

Ek9

I use only Brembo blanks these days. I get them from Tire-Rack. Sure I could get cheaper blanks but, in my experience the Brembo's hold up to heat better than other rotors I've used. I've never warped them after many track sessions. I do get some crazing on the surface, small cracks, but, I've never had them grow beyond that.

I always bring spares too.

I don't turn rotors when they go bad (which hasn't happened yet with the Brembo's) I toss them and get new ones. For the price and the usage I put them through. Why risk having a rotor break? You might put your nice S2000 into a wall if they break at the wrong time.

Was at the track not too long ago when an RX-7 split a rotor. He was pretty lucky and nothing bad happened.

Nobody

Thanks for the info. I tend to go through rotors quite frequently and at $160 a piece (Wilwood directional vaned rotors) I don't have the luxury of just tossing 'em. I've never had one crack except at RF where my brake temps were close to 1000 deg and there were long straights for maybe too ample cooling (I think it was the hot/cold/hot/cold that did 'em in).

And thanks for the tire pressure info Raymund.

Raymund

yeah, all that tech stuff makes more sense when you take in consideration that spare tires are inflated to 60psi.

loudes13

ii've terminally cracked 2 rotors already this year. i might try some brembo blanks though. the s2k rotors are kinda expensive.

s2k $60 each
C5 $25 each
miata $60 each
e36 M3 $40 each
crx $18 each

I found that the miata and bmw rotors lasted the longest. Some matter if brand name, some don't.