After much hard track use and a good amount of street driving, I am thinking that it would be a good idea to replace my front brake rotors. Just looking for a second opinion once you take a look at the pics.




thanks in advance

 

How think are they? I have 35k miles, one track day and have lost count of how many autox laps on my OE set.

 

Yep, until you mic them, no way of knowing...

How much are RX8 rotors, anyhow? OEM quality replacements for the Z06 were $22/ea...no shnizzit...

 

mine have 33k miles, and prob about 10-15 track days on Road America and another local track

 

That is a lot of laps on a fast track. Buy a new set.

 

They were made of the same stuff as your fake gold chain, crushed Buicks.

 

Why? If they are not too thin or showing any signs of spiral cracks, just run 'em...

crushed Buicks?

C'mon, you know all my bling is the shnizzit, no fake gold for me

Besides, you think oem RX8 rotors are "better" than NAPA replacements?

 

na---you dont know til you spec them. Heck i had 46K (not a lot of city driving) and at least 20 days on the track on my front ones. then i had them turned and they are just fine. The rotors are one thing mazda got right.
But who the hell needs brakes anyway!!!!!!!!
olddragger

 

I wouldn't replace them, they'll just slow you down ...

 

if you were in FL I'd sell you mine. Got OEMs in boxes in my garage

 

Me too! Me Too! but I'm in Florida as well!

 

are those cracks really not that big of a deal? I thought as soon as you saw cracking you should ditch them and get a new set

 

I could not tell you what is a good RX-8 rotor, still on my first set. I will buy OE ones from Mazda Motorsports when I need a set.

On the C4 I had a great hook up, I paid less than $50.00 for all four rotors. Schotz is doing the same thing on his T2 fbody. Why pay good money for rotors you are going to burn up in one weekend.

 

I just looked at the first picture again and can now see the cracks...first pass, I didn't notice any and I can't make out any in the second and third pics. I can't tell, with the resolution, whether its just short heat checking type stuff or not? If the cracks extend all the way to the outside of the rotor or if they are wide/deep enough that you can really feel them with your finger, replace 'em, for sure

For track use, I would NOT spend up for any slotting or drilling. Slotting may make some sense, but is of minimal value with most current track specific pads. Drilling has no upside, besides bling factor, and much downside. As a matter of fact, plain iron rotors, all other variables being equal, will be more functional and will save $$$ for pads and tires

 

I am the shiznit.

 

hope your autoxing is better than your jokes .....

 

Don't be a *****.

have them turned and see if it is any deeper than surface. then decide.

 

This should be good...


anyone up for brake tech 101?

OK, I'll stop trying to be a smartaxx. With modern rotors, there just isn't enough meat to turn them and retain sufficient thickness. Even old school rotors were marginal at best for track use after being turned, due to the loss of thermal capacity, as you brought them close to minimum thickness. So, as long as the rotor has enough left to be in spec for thickness, the only "resurfacing" it will need can be accomplished through bedding in a new set of pads...unless you have a situation where the new pads are not capable of scraping off the transfer from the prior pads, then you'll get uneven pad transfer, with squealing, chattering and all the good stuff. If that's the case, you can scuff up the rotors with a Scotchbrite pad on a drill or one of the tools now made for that job...but, you aren't taking any metal off, just brake pad transfer.

That's if the cracks shown in the first picture are just heat checking, which is normal in high heat use. If the cracks go all the way out to the edge of the rotor, or are longer than it looks in the picture, or can be felt by running your finger across them, then the rotor is no longer safe for track use...at least that's the rule of thumb I've been taught.

disclaimer: I'm no engineer and I didn't stay at a Holiday Inn Express last night.

 

that ain't no joke ....

http://www.lvrscca.org/race-results/...ound07_pax.htm



and don't let Woody fool ya', it was really a Motel6


.

 

blue
there is a dye you can use to check for cracks. If the rotor is truely cracked you are correct in the fact --DO NOT USE.
I havent seen a cracked rotor on a oem front rx8.--they are pretty good.
True whenever you "turn " a rotor you do lose some material and the heat sink factor does decrease---but as long as it is still within factory specs it will still work for autocrossing and track days---maybe not a full race prepared car in competition but hell they need ducting anyway. It is a matter of degree.
We just need reverse thrusters.
OD

 

thanks OD. So am I correct in just looking for cracks that run the radius of the rotor?

 

well, it feels like i have some buildup on the rotors too, I will spec them and see if they are still usable after some light machining, otherwise i have a set of slotted OEM's that could be pressed into service

is there a concrete answer to if you can machine slotted rotors or no?

 

Blue,

When I had the same surface cracking on my OE rotors after several DE weekends, I decided it was time to replace them rather than risking cracking one and being stuck wasting a DE weekend.

I went to www.rx7store.net and got a set of the Brembo rotors that were then slotted (can't get just the blanks from them) (http://www.rx7store.net/category_s/269.htm). I didn't want slots and WOULD NOT GET DRILLED ROTORS FOR THE TRACK, but the slotted ones were cheaper than OE rotors so I got them. They worked great. Maybe better than stock, but I can't honestly make that determination. They weren't any worse, so that was all that mattered. The pads were the only thing that made a difference, so the rotors don't really matter for performance. I was running Hawk HP+.

I still have these rotors, as well as some other parts, but my RX-8 lease has been turned in (hell yes... I leased it and tracked the hell out of it!). Someone already PMed me about them, but I was thinking $200 + shipping. They look almost new and there's no warpage. The RX7Store was great to work with, btw!!

 

I was hoping to not have to spend almost $400 on rotors, I just keep having brake pad buildup on the rotor, causing shaking in the steering wheel when I brake from a high rate of speed. The only was I know to remove that buildup is to get them turned

 

It doesn't sand off?