Gents,

I have a set of 225/45 NT01s that have worn very evenly running 2.7/2.3 degrees of camber F/R. I just did three days at VIR, and there are no wear holes showing on any tire. How much life is left? I'm heading back to VIR this coming weekend.

Thanks,

 

Tread life depends heavily on the track, the car (aero or not) and on how hard you're driving. I've only run NT01s on my BMW, but if they're worn as much as you say then I would not expect another day out of them.

Also, IME the story about how "NT01s are fastest right before they cord" is a myth. I've seen 1 to 1.5 second lap improvements at Laguna going from a worn set to a brand new one.

--Ian

 

Bring another set with you.

 

I've never worn a set down this far. For the last several years, I've been pulling a Harbor Freight trailer with slicks, and drove on my rain tires. I never wanted to burn up a set of slicks while there was still track time left, so I probably swapped them out too soon. I bought a car trailer early this year. I should have done that a long time ago.

 

I’d suggest the worn set had something else going on then, rather than the tread depth affecting the speed.

I ran NT01s for 4-5 years before moving to A050s, and always found them to be consistent for speed right through their life. On several occasions I set my fastest times just before they corded, but also set some fastest on their second day. Did not show any real degradation in times over their lifetime. Repeatable over 50+ events.
(Usage was track only, not driven to/from events, removed and stored in dark between events. Not sure if this matters)

I did however flat spot two due to a 360, and replaced the two 50c shaped ones with second hand tyres off a mate (which had been stored correctly between events) with slightly more tread than mine and they were atrocious. So iME tread wear is not an indication of lap speed potential, at least for NT01s

 

This experience has been consistent across the last 7 or 8 sets I've used. 3 track days that are pretty consistent, then one when they're sliding all over the place and 1-2 seconds slower. Sometimes cording before the end of that 4th day, sometimes they've got enough left for another half day on them.

This is not a Miata though. 275/35R18s on an E46 M3 with aero. I never ran them on my Miata.

--Ian

 

Do you drive the car to/from events? That's the only difference I can think between my sets and the set I borrowed which should have been the same but def weren't.

Also I wonder if the bigger heavier car makes the difference? Mine were all 205/50/15 on a 2200lb miata.

 

Nope, caged, trailered race car. 2750 pounds without driver.

--Ian

 

They're done.

This video might help. Different brand but the indicators are basically the same

 

Great video!

Thanks much,