OK, so I now have about 180 track day miles (2 days) on my Nitto NT-05's and while I love the way they handle they are about 1/2 way gone in the front and maybe have one session left on the rears. I will obviously swap them, but that does not seem like a ton of miles when I see other folks talking about 7 or 8 track days out of tires.

Also, the middle of the tire is wearing faster than the outer part of the tire - I run them at 40 psi hot. Is that too much air pressure? Anybody run these at the track and have found a better solution? BTW, the car is a 1991 Z07 with 275's all the way around.

How far can I run these down safely in the dry? Forget about the wet - I don't care.

--Calvin

 

What was cold pressure ?
What track did you run ? Putnam tears them up pretty fast .
180 miles is pretty quick

 

They were about 32 psi cold, 40 hot. The track is High Plains Raceway outside of Denver - 2.5 miles with about 70 feet of elevation changes and grades as steep as 10% in some places.

 

Wow, that one is out in the middle of bum **** nowhere!

Looks like a BLAST though.

The pressure sounds about right to me. You could deflate them a little bit and try to get that hot pressure down to about 35-38. But you would have to be careful until they got nice and hot. You don't want to blow a bead on that back straight. Noone will know your there!

Seriously though, when I get back to San Diego, I might just have to road trip the Vette up to MN and hit up that track on my way.

 

Anytime, I would be happy to meet up with you out there. It is only 65 miles from my home in suburban Denver. It is a really fun track - I have posted some videos on YouTube if you want to follow from the driver's seat. It is such an awesome deal! I could have gotten 4 hours of on track time for $90 yesterday if I didn't have to go back to get gas (17 miles away unless you want to pay for racing gas). As it was, even with taking breaks I got about 2 hours of seat time.

YouTube Link:
http://www.youtube.com/watch?v=kctd8...eature=related

On further inspection of the tires they are at 3/32's depth on the back and 5/32's on the front. The middles of the back are about 0.5 to 1/32 more worn than the sides - which doesn't sound too out of family. I think I can run these guys down until I get a good bit into the wear bars, since I don't care about dry traction. I am guessing I will get about 260-280 miles out of them before I have to toss them. Not horrible, but not great either. What do you run on the track for tires?

 

If the tires are worn in the middle, they are over-inflated. Pressure is only part of the equation however. Wear patterns and tread temperatures are the other elements you have to consider.

The treadwear is 200 on the NT05, so it is a high performance street tire vs an R-compound tire like the NT01. Even the NT01 is not extreme with its 100 tread wear rating. The NT05 It should last way more than 180 track miles. That tells me your alignment likely needs adjusting in addition to your tire pressures.

FWIW, I am nearing 800 VERY hard miles on a set of NT01s. I should be able to get another couple hundred miles out of them.

 

Wow, 800 miles! That's all on track? My alignment specs are straight up on toe and 1 deg negative on camber with a caster in the 5.4 deg range. Any suggestions?

 

A good friend/customer of mine has the same NT05 tires on his 91 (383 Super Ram with a 6spd) and didn't get more than 6K miles out of the rears - just regular street driving before they were down to the wear bar in the center.... I had the car for a week or so to fix some ignition problems after we built the engine and the NT05 had decent grip but nothing like a real track tire IMO. His car has the VB&P recomended Auto-X alginment.

In your case 180 miles even track day use does seem a little extreme - but from my first hand eyes on these tires they don't last on a high HP car.

Heck I run MT Drag radials on my 92 6spd and have over 7K miles on them (street) and over 40 passes at the track..... they were still fine to drive the car all the way to Carlisle PA (400 miles round trip all hwy)and back in a hurricane...... I'm still gonna be able to run them until the end of the racing season up here.
Will

 

Nearly all track miles...I live 8 miles from Pacific Raceways which is where my track days and HPDEs are. That's pretty much the only time I drive the car.

You need more camber. Up front, you want as much as you can get. My car is slightly lowered and I machined the spacers that go between the upper a-arms and the frame. By doing that, I'm at -2.2*. I run 0 toe and as much caster as I can get....6* comes to mind (I'm out of town and don't have access to my alignment notes). In the rear, I run -1.9* camber and 1/8" toe in on each side. Being a GS coupe, my tires sizes are 275s up front and 315s in the rear.

I have a 30mm front sway bar and 26mm rear sway bar. Shocks are Koni adjustables.

The car still pushes a little on corner entry, but not too bad.

I would start around 30 cold in the front and 28 cold in the rear.

If the track has a lot of turns to one direction...ie more rights than lefts or vice versa....you can experiment with staggered set-ups, both in terms of alignment and pressures.

Chalk or shoe polish the tire sidewalls and part of the contact patch. Look for sidewall roll-over after a run.

While not ideal, you can buy an IR temp gun for less than $100 so that you can check tread temps after a run session. You should be looking for even temps across the tire. A temp probe is really the correct tool, but the IR gun will suffice and you can use it to check brake rotor temps, caliper temps, etc

Keep in mind that most advice you'll read on the internet is geared towards an R-compound tire. What works with those tires (ie hot pressures around 40psi) may not be ideal for a street tire.

 

Thanks for the info! It's funny, that track is close to where I bought the car - flew up to Seattle to purchase it and drove it home. I know I kind of compromised on the camber since I am still driving it a bit on the street. Since my car is the Z07 I am running the same size sways you mention. Your mention of toe in on the rear made me re-look at my sheet and the alignment shop screwed up. I told them 1/8" toe in, and they set it at 1/8" toe out! However, I don't think that would cause excessive tire wear, just maybe a little bit of rear end "looseness."

 

eekkkkkkk!! I keep my hoho's rotated and pressure down and they last a season.

Reminds me I need to find $1400 soon so I have tires for the end of my season.

 

wait-wait-wait you pressure is way to high thats why ure thin in the middle.. you should only be at 30-35 hot if wear is different on inside or outside of tire its a camber issue you tires should wear all the way (and its ok if it goes a little over) your little indecator arrows on the side wall..

 

30-35 hot??? Wow, that means I would be starting out at 27 psi??? That seems a bit low for non-r comp tires. I think I will try going down a bit next time, maybe somewhere around 37-38 hot. After further examination the wear on the middle is only about 10-20% more than the edges. The shoulders look awesome. Even on both sides and not chewed up/rolled over at all.

 

agreed a bit low but still ok get a pyrometer make notes of your tire temps outer inner and center..u are using these as r comp tires.. ill start my r comps as low as 22....they get hot fast and pressure rises quickly... a little roll over is ok ....like i said to and a little over the wear arows...

 

a pic of the tread wear could help

 

"If the track has a lot of turns to one direction...ie more rights than lefts or vice versa....you can experiment with staggered set-ups, both in terms of alignment and pressures."

If you come back to the same spot, you know you have more turns one way than the other unless the track goes over the top of itself.

 

.

A track with chicanes and can balance out the number of official "turns" even if the chicanes are not officially numbered as turns. None the less they can cause a track to have an equal number of left and right steering wheel inputs/weight transfers. Haven't been to many different road courses have you.