Nitto NT05 tire test

[emilio700]

Test conditions:
February 20, 2009
Speedventures
37~70° dry
Streets of Willow CW with blowpass

Vehicle:
2003 S2000
8xOEM 17x8.5" rear wheels
APR GTC200 rear wing
Tein S-Tech springs

255/40/17 Tires:
Nitto NT05 - Sticker tires
7/32 starting tread depth, 6~7/32 ending tread depth
Ending durometer reading at 60°: 74 shore A

Dunlop Z1 Star Spec
Two events on them
8/32 starting tread depth, 6~7 ending tread depth (10/32 when new)
Ending durometer reading at 60°: 74 shore A

I wanted to run the Star Specs down to where they had the same depth as the NT05 before comparing. The caveat is the Star Specs had two events worth of heat cycles in them. They felt just as fast as they did at Buttonwillow last month when they were stickers.

Well I can say that I was honestly surprised at how much like a pure race tire the NT05 felt. Crisper, more linear steering feel than the Star Spec. Where the Star Spec begins increasing slip angle well before maximum grip, the NT05 rolled cleaner and developed max grip at smaller slip angles. This necessitated a more precise driving style but the rewards was being able to consistently get closer to the apexes and track outs. Not to say the Star Spec was sloppy by any means. In fact the Star Spec felt very good but had a tiny bit of "rubberiness" in the steering when developing maximum grip that the NT05 did not have. It could be sidewall but I believe it's more the Star Spec tread design being more street oriented in my opinion.

What I did notice in my notes was that the NT05 did not initially "feel" fast even when it was setting its fastest laps. Being accustomed to the slightly larger steering angles the Star Spec liked, I was feeling the NT05 breakaway and lose grip. In fact, I was turning just as hard but simply steering too much and going past the NT05's optimum steering angle. Overall, I think the closer to optimum the car is set up and better the driver, the more and advantage the NT05 will have. Bad set up and sloppy driving, the Star Spec will probably provide more consistent lap times due to it's more forgiving nature.

The Star Specs seemed to like about 37psi hot, tread temps coming up to the 160° range when ambient temps were close to 70°. The NT05 seemed to work better than the Star Spec in morning when it was colder. As the ambient temps came up, they were closer together. Based on pyrometer readings the NT05 seemed to want a bit more pressure, 39psi.

Wear on the Star Spec's has been very good, considering their prodigious grip. They set the bar rather high so I was concerned that the lower starting tread depth of the NT05 meant they might be softer and faster wearing. This was not the case. Indeed, the inside tires (NT05) still showed 7/32 after having been flogged by three different drivers over 5 sessions. Neither tire showed anything like chunking or tearing. The Star Spec's taller tread showed some slight feathering and tapered wear from the last two events so we flipped them on the rims for this event. The NT05 showed no feathering or tapered wear. I suspect this difference is due to the larger, interlocking shoulder tread blocks on the NT05 compared the smaller blocks on the Star Spec.

The negative G's and slow right handers of SOW CW had my AP1 sucking oil through the breather and smoking. A common issue I had not encountered at previous events so I rigged a plastic oil container and some hose from autozone into a catch can. This and a few other logistical issues caused me to miss two sessions so I never quite got the the NT05 pressures exactly where I wanted them.

Fastest NT05 lap: 1:27.2 in 37~40° ambient
Fastest Star Spec lap:1:27.0 in 70° ambient

Due to the missed sessions, I feel that I never quite drove the optimum lap on the NT05 so these lap times are not definitive. I like the steering feel of the NT05 sufficiently more to switch. I'll be on the NT05's for the next S2K Challenge event.

[momofoolio]

nice report!
thx for sharing emillio!

but how abt the prices?
is star spec cheaper?
and is star spec tread 180 or 200??

[JDMxDB8]

Nice review Emilio. Too bad the NT05 isn't available in 15s...

BTW, props for tracking with S-Techs.

[0.o slow 1.6]

Very nice review.

[.:Made in OC:.]

Originally Posted by JDMxDB8

Nice review Emilio. Too bad the NT05 isn't available in 15s...

BTW, props for tracking with S-Techs.

I agree. Nice review Emilio.

-Charles

[Stuntman]

Originally Posted by emilio700

Fastest NT05 lap: 1:27.2 in 37~40° ambient
Fastest Star Spec lap:1:27.0 in 70° ambient

Due to the missed sessions, I feel that I never quite drove the optimum lap on the NT05 so these lap times are not definitive. I like the steering feel of the NT05 sufficiently more to switch. I'll be on the NT05's for the next S2K Challenge event.

How hot did the NT05's get up to in that cold of weather? 160*F seems on the lower side (Starspec) of a street tire's operating range, no?

[AIREKone]

Nice! I've been waiting for someone to do a test on these tires.

I just ordered myself a set

[emilio700]

Went back to Streets of Willow (CCW blowpass) for the Speedventures S2000 Challenge Time Attack yesterday. Added some camber adjusters to get some much need front camber and maxed out stock rear camber adjusters. We found that the NT05 does need to be heated up to at least 150° to really start working. We also found that, in our environment and test conditions, the tires wanted quite a bit less pressure than the pyrometer would otherwise indicate.

We ended up with 34-36psi hot on the S2000 and managed to reset the street tire lap record at 1:25.754. That may also be the street tire record for all cars.

[Richard EVO]

Nice work, emilio. What do you think of the NT-05 as a street tire? I don't mean a street class tire to run on the track, I mean a tire to run on a daily driver that never sees the track. I have been running full tread RA-1s as my street tire on my daily driver Evo IX MR. They make good street tires and last about 17,000 miles. I need to replace them soon, and have been trying to decide about what to get.

[emilio700]

I've now done some street driving on the NT05's and they are surprisingly benign considering they are basically race tires. Minimal tramlining, very quiet, overall mild NVH and tread slap. I'd keep running them but I want to save them for the S2000 Challenge events since they're so damn fast. The bargain close-out RE01R's I just ordered from Tire rack will be my new street tires until they wear out. The Star Specs will be the track tires for regular track days.

So yeah, very nice if you want a sticky and fun to drive street tire that will last longer than a pure race tire.