zhenyang huang

Hi guys,

My rotor life might last less than 2 track days, especially the front rotors.
I did 1 track day on oem pads and 2 track days on re10 pads.
Just curious about your guys' rotors' life and any suggestion for the upgrade?
And also where I can get cheaper oem rotors?

Thanks.

jphughan

AP Racing 2-piece rotors seem to be the overwhelming favorite in the GT3/GT4 segment. I've got a pair of fronts I'll be installing whenever I need to replace my pads. But 2 track days is absurdly fast for front rotors. OEMs on the GT3 side seem to last at least 8-10 days before cracking due to their drilled design becomes an issue, and the slotted AP rotors have been lasting more than double that, so the same hardware on the GT4 should be lasting even longer. Or do you mean they might be lasting less than 2 more track days on top of the 6 you've already done? That would still be a bit fast from what I've read but at least not completely ridiculous.

If you want to stick to OEM and get best pricing, Suncoast is usually your best bet, but the AP rotors allow you to replace just the friction ring separate from the hat, so you would be ahead cost-wise the first time you do that even if they didn't last longer than OEM, which they do. 2 sets of OEM front rotors from Suncoast will cost you $2800; a set of AP rotors plus a replacement set of friction rings will cost you $2600, not considering the Rennlist discount offered by some vendors.

PM Clark-ApexPerformance if you want to go with the AP option. He's taken care of several members here, myself included.

ShakeNBake

Can you send pics?

That seems totally out of the ordinary. Front OEM iron rotors last 10+ days with a strong driver on race pads.

zhenyang huang

ShakeNBake

Those look fine. What is the measured thickness relative to the stamped min thickness?

zhenyang huang

I mean 2 more left. Total gonna be 8-10.
Thanks for your suggestion.

zhenyang huang

quiet confused about what you said sir.

needmoregarage

I see only a few cracks. None of the cracks span between (connect) two holes. None of the cracks are at the edge. None seem excessively large but it's hard to know measurement just by eyeballing a photo. Look maybe 5 mm? is my guess.

Isn't the guideline to replace rotors with 10 mm cracks, or if a crack connects two holes, or if the edge has cracks, or if thickness is depleted which can be diagnosed by how much of a ridge forms around the edge or by measuring the thickness of the rotor and comparing current measurement to when they were new (how thick were they brand new)?

Looks like the beginning of normal wear. They look like there is still plenty of remaining life. Interested to hear what others say.

jphughan

Steel rotors have a minimum thickness stamped into them. One way rotors can reach the end of their useful life is if they're worn down to that thickness as measured with a micrometer; less precise tools won't be very useful since the difference between new and minimum thickness might only be 2mm. But if you're not near that number and don't have any serious cracks in the rotor (those linking drill holes and/or extending all the way to the outside edge of the rotor), then you're fine.

So maybe the better question is: Why do you think you only have 2 more days on those rotors?

zhenyang huang

Thanks a lot.
Cause one of my friend told me I might need to replace them after he saw the picture.
He is not an expert so I just post a thread asking for help.

ipse dixit

I think you need to find new friends.

mooty

keep driving u are at 50%
don't worry