Nitto NT01 tyre/tire query
 

I have just returned from a weekend sprint and have to say I have never felt my car be so unpredictable on the limit before.

I have previously run a range of tyres types including Hoosier R6, Hankook twin grooves, kumho slicks and more recently Yokohama A050's. I have also recently changed the worn front A050 to Nitto NT01. On the front these seemed to work OK, perhaps not quite as grippy as the A050.

I recently changed the rear from A050 to NT01 as well. I had run these at another track and noticed they were not as predictable as the A050 and laps were around a second slower on a 1 minute track.

However, last weekend I drove these on a different track. The track had been resurfaced a few months ago, the surface being very smooth. This is where the 'fun' started. Straight away the car became really nervous on high speed corners and the back would slide out both on and off throttle around the tighter curves. The tyres were also squealing like a pig on the new surface. On several ocassions the car would drift with the rear end out. The car was an absolute pig to drive near the limit. The tyres actually felt better when they were cold and got worse and worse. I tried tyre pressures from 29 to 36 hot and it made bugger all difference. Rear tyre wear was perfectly even, in fact there was hardly any wear.

Interested to hear if anyone else has had this experience on the Nittos, particularly from track to track. Any chance these rears could have been a bad batch?

I just can't believe that the fronts feel ok, but the rears are just horrible. The A050 old rears worn to the limit had better feel and grip than these.

That has not been my experience with them. To me, they feel like a real high end street tire and are very predictable.

Don't know what to suggest except possibly your alignment. Perhaps someone else can offer more insight.

-Mike

What suspension do you have?

I've driven them a LOT on a 996 and a 981 Cayman S. I've only seen what you describe when they are completely cold - first lap on a cold day. Once I get them warm and good pressure, they're really predictable and fast. Could be the new track surface... I had fresh NT-01s once on a newly resurfaced track and had a tough time for a bit. New - they DO take a couple of sessions before they grip really well. Good luck!

Sounds a little odd Eric. I used to like them on my old car. I think we ran them pretty high pressures but it's so long ago...hard to remember. They wouldn't be up to the A050's performance in my opinion but they were the best R spec I had ran up until 2010. Tread squirm? What about the date of production? Some of those numbers on the side can read like obscure codes but if you bought them from some of the known suppliers in Sydney they might be older?

I tried NT01s for the first time this season due to all of the positive feedback I've read. I did not like them at all on my car. I found the front to be undersized relative to the rear for my particular application (inducing copious amounts of understeer). And yet...they squirmed significantly under braking...a confidence destroying issue I've never had with any other tire. However, I found them to very predictable (hot psi 31-33).

In fact...if anyone is interested...I will be shortly listing 2x 245/40/18 and 2x 275/40/18 for cheap. The 245s are in the sweet spot for tread wear and the 275s have visible tread left.

To me this is the big question. I found the NT-01's to be incredibly predictable. On a cayman platform, the big issue I found was that over 30PSI they start to get squirrelly and it would take 3 2-minute laps to get just the right heat in them. If they made them in the right size for my set-up I'd still be on them.

I went through a few sets of NT01s on my E90 M3 and found that the first couple of sessions on a brand new set were terrible. They were squirmy, squirrelly, pretty scary. Thought I made a huge mistake with them. But once the mold release compound was burned off the surface and the tires were scuffed a bit, they were great. Good grip and very, very long life. They're loud, both in steady state due to the tread pattern, and in squeal when loaded in corners, but some people like that degree of communication.

It sounds like you've put a few sessions on these, though, so that initial scrub-in period should be complete. Maybe Nitto has changed the tread compound or composition for the worse recently?

After the NT01s I moved on to the newer Toyo Proxes RR on my M3, and those were fantastic. Significant step up in grip over the NT01s, but more like a Hoosier in not communicating as much near the limit, and wearing out twice as fast as the NT01s.

The tire world may have moved on relative to the NT01, because tires like the Pilot Sport Cup2 and Bridgestone RE71R probably offer more grip on track, and yet are streetable.

Thanks all for your responses. To answer a few questions, the production date is late 2015 so not that old really. Suspension setup is as follows

Porsche 944s2 supercharged

350f springs, Kong sport shocks
225r springs plus t bars, Koni 30 series shocks
30mm front sway, 19mm rear sway on softest setting
3.25 front camber, 2 rear camber
Slight toe in rear, zero toe front

235/40 17 on 8.5" front
255/40 17 on 9" rear
Standard LSD (6 years since rebuild). Yep, time to pull he lsd and check wear.

Tyres had about 30 laps on them before the sprint.

I did notice they didn't get as hot as normal. It was a cool day, and perhaps the cool surface had an impact on performance.

My .02

01 - when new they squirm ALOT. Usually takes 8-10 heat cycles before they really start to get good.

02 - I've never driven any tire (hot street tires included) that required as much slip angle to go fast. Once you realize that the tire isn't really "unpredictable" as much as it just moves to get into it's sweet spot you will get comfortable.

I will agree that tire technology has come along way and street tires such as RE71R as just as quick if not quicker these days compared to the Nitto.

I had similar experience at the Glen after repaving on brand new set. It needed a session to wear in and even then it was a bit lose and squealing. At another event later in the year, it was back to normal like on other tracks. I really like NT01s for my application. Still gives you audible warnings when you are close to limits, progressive and wears really well.

I have a first gen Cayman and I adore the Nittos (245, 275). Very progressive, with tons of grip and I have not had them go squirrelly or give any indication of upredictability.
They do seem to be quite sensitive to pressure as I can feel them lose grip once they are over 34psi.
30-32psi (hot) is the sweet spot on my car.

I went from MPSC to NT01 this year because the Cups were no longer available in my sizes.
Glad to see this discussion because I though it was just me getting use to new tires after 10 years with the Cups, definitely a confidence reducing experience.
After two days I found the NT01 to have a softer shoulder, needing a lot more slip angle and as well quite squirmy. Ended up with pressures at 32/35 on my 993 at WG.
Hopefully like NYC993's experience they will get better after more cycles.

While we're soliciting opinions here - what pressures do you personally prefer/recommend for a 996 (GT3) setup?

I spoke to someone today running 32 all around on his 2004 GT3 - sounded low to me, hence the question.

Cheers

Matt

I ran around 35 all around on my 996.