Are Nitto NT555 tires good for HPDE?

[Chill out]

Anybody have experience running Nitto NT555 tires or NT05 tires for HPDE?

Any tire suggestions for HPDE on a S197.

Do 18x10 wheels fit the front with a 275/40x18 tire?

[Trevor57]

The best tires for hpde are cheap or free. Grip level doesn't really matter, so tire life is the priority. I always loved the ra1 since they seemed to last forever.

[D Algozine]

Anybody have experience running Nitto NT555 tires or NT05 tires for HPDE?

Any tire suggestions for HPDE on a S197.

Do 18x10 wheels fit the front with a 275/40x18 tire?

 

As Trevor stated, cheap and long lasting, which typically means Toyo RA1's. Especially since you should be able to buy used race tires from AI guys. You should be able to buy used RA1s with good tread left for very cheap. Ask around in your region. In addition to AI you can check with STR and SU guys also. They may have other brands, but costs should be very little compared to new.

[Chill out]

What are STR and SU?

 

Are Nitto tires worth considering?

[D Algozine]

What are STR and SU?

 

Are Nitto tires worth considering?

 

STR and SU - Upper series of racing class, includes mainly Corvettes, Vipers, or other highly modified cars. Some may have the tire size you're looking for.

 

Nitto's are as good as any. I used them early in my HPDE driving several years ago. As I recall, they didn't last very long, but that was a while ago. My memory may be off, and/or they may have changed over the years.

[Houstonnw]

How many HPDEs have you done and why are you considering r-compound tires?

 

I did over 10 track days on the Pirelli PZero Nero all-seasons on my '07 Mustang GT. I only moved up to summer tires when I was put into a faster group and was simply in the way (not NASA).

 

The Kuhmo ECSTA SPT tires were fine for another year and a half until I started doing Time Trials and needed the extra grip of the NT555s. From my experience (or lack thereof), they seemed to lose a lot of grip after the first few temperature cycles. Toyo RA1s can be run down to the cords it seems. I also chose the Nittos to drive back and forth to the track. I found out the first time driving home in the rain that a tire trailer was a good idea.

 

But it really comes back to why you want them. Sure, the r-comps will make the car faster, but you won't be.

[Chill out]

The NT555 I'm looking at is not a R compound. I want a tire that will hold up to a 30 minute session (if I drive right). I'm looking for longevity over grip. Yes, I have overdriven my Prielli's. I need a lower aspect 18-inch wheel/tire, and there are too many choices.

Any help is greatly appreciated.

[bluefirepony]

You should be fine with the NT555s. The NT05's treadware rating indicates it probably won't last as long as the NT555...never driven the NT05 though.

From personal experience, the NT555, Khumo ECSTA and BFG KDW's seemed to be roughly the same on a stock S197. The Khumo's took longer to come to temp but once there ran very consistent and lasted a heck of a long time as did the BFGs - I think I still have a set of each from several years ago - in fact my son ran DEs in our race car on an old set of Khumos. When I was running DEs I drove to and from and ran my sessions through multiple weekends on the BFGs and the Khumos.

Never ran the NT555s for a heck of a long time though so don't really have any evidence on how they would last but the few times I ran them they did fine. So as was already said, just get the cheapest.

 

As for the 18x10s with a 275x40...that's probably a size too big for the front by way of interference and inducing more push on a stock front end. I run 18x9.5s with 275x35s R-comps and generally went with 265x35s and 265/40s on the street tires above.

[QUASAR]

I can't speak for their street stuff but I have had success with the R compound nittos. Both 555R-II and NT-01. And they last forever. My 60+ heat cycle nittos have been faster than new 888's or RA1's. The best tires for HPDE are cheap or free scrubs. Unless you want to be HPDE champion, that will take a new set of A6's.

[robbodleimages]

nitto is a sister company to toyo. the tires are the same compound with slightly different characteristics. the nitto will do you fine. btw...275/35-18. not 40

[Chill out]

Good info, thanks.

 

I thought a wider front tire 275/40 would REDUCE PUSH? I installed Strano adjustable sway bars and have 1.9 degrees negative camber.

 

Also, running a 275/35 will reduce my tire diameter about 1.5 inches. Any problems there?

 

Any advice on how to treat new tires? Heat cycle?

[robbodleimages]

no problems. the grand am spec size for the mustang 18" wheel is 275/35-18

[bluefirepony]

I thought a wider front tire 275/40 would REDUCE PUSH? I installed Strano adjustable sway bars and have 1.9 degrees negative camber.

An increase in tire/rim size can, taken by itself, suggest an increase in cornering stiffness, but with all the dynamics coming into play, in order to take advantage of that, you need to consider the responsiveness of the tire and also on the big arse beast known as the S197, you need to have a rear end setup that can keep up...the stock S197 rear end is REALLY slow on street tires even with a stiffer rear sway bar until you do more (all or multiple of : chassis stiffening, ride height, responsiveness of rear components, etc.).

Assuming you get addicted like the rest of us, when you dip into other goodies you'll eventually get a rear end that can keep up. My opinion, my experience. Your results may vary.

 

Also, running a 275/35 will reduce my tire diameter about 1.5 inches. Any problems there?

Nope. In fact you can probably run that size w/o having to change the rev miles setting on the spanish oak - though I do and probably best to be safe - I think its like 801 or 810 or something - depending on the tire manufacturer. I had one set of tires that was just outside of the range and caused the car to go into limp mode.

 

Any advice on how to treat new tires? Heat cycle?

Just watch the pressures...assuming you are going with the 300 treadware tires (i.e. not the NT-05) you should expect the tires to take a while to warm up. All three (NT555, Khumo and BFG) seemed to squawk pretty consistently at limit and are pretty forgiving...of course they dont' have nearly the grip of R-comps.

[Chill out]

You got me again, what is spanish oak? how easy is it to reset? (Is this like a snipe hunt? I'll hold the bag, you get the flash light.)

 

I'm trying to reduce the tire rolling over onto its shoulder.

Tire choices are 255/45x18 . . . only 15 mm shorter sidewall than stock 235/55x17 OR . . . 265/40x18, which is 23 mm shorter than stock. I agree 275 is too much on the front.

 

How can I reduce tire roll over?

 

Rear end too slow? Can you explain.

 

 

"Addiction" . . . I turned 60 this year and I Am trying do it all in one summer. I raced motorcycles at VIR when it was asphalt and cornfields.

I hope you guys aren't laughing at me!

Thanks for the replies.

[soundguydave]

You could consider "Spanish Oak" as the operating system that the PCM (Powertrain Control Module) runs, much as Windows, OSx, or Linux is to a laptop. If you're putting an S197 on track, one of the FIRST things you should do is get a proper tune for it... Takes minimal hardware (SCT or Diabolo flash updater) plus a tune, available via email from a variety of different tuners. I use Eric Brooks (brooksspeed.com), and he's excellent. A solid basic tune will get you much crisper throttle response, a handful more power, but most importantly, the ability to start really getting the response of the engine sync'd with your desires and driving style. With Spanish Oak, EVERYTHING is adjustable, even things that traditionally weren't, like how quickly the revs fall on a throttle snap.

 

You're heading in the right direction with the camber, but I would run as much negative as you can get your hands on, particularly with everything else being stock. For the bars, Sam's pieces are killer. Try running the front on full soft (hole furthest away from the front of the car), and then play with the rear bar setting until you get the balance you're looking for. For me, it's in the middle position, but I have a LOT of other stuff done to the car.

 

As for tires, I use Dunlop Direzza Z1 Star Spec in 275/35-18 on all four corners for street rubber and for rain tires, and they're at or near the top of the heap as far as non R-comp tires go. I used to use the NT555, and believe me, the change from 300 treadwear to 180 treadwear is night and day. 275 is NOT too much up front! Whatever size you go with, stay square, with all four corners being the same size. The car is set from the factory to understeer quite a bit, and putting even more meat on the rear will exacerbate the problem.

 

If your main complaint is that the tire is rolling over on the shoulder, then the extra negative camber will help, as will hiking the air pressures up a bit. If you normally run 32psi on the street, start at 35 or 36, and see how that does for you. Buy a tire crayon, and color in the "shoulder" of a tread block on each tire, and adjust tire pressures so that you're not wiping off the crayon. You may need to run staggered pressures, like 36 up front, and 34 in back to get to where you want to be. The pressure variation will also help to tune the behaviour of each end of the car, as well.

 

As for "rear end too slow," I think Bluefire is referring to the inherent understeer designed into the car. He's right, though, until you start making significant changes to the chassis and suspension, the car will tend to push, and pressures and bars will only do so much. Having said that, though, you should run the car stock as long as you could, until you know you're wringing 100% out of it, leaving nothing on the table, and then identify exactly what it is that is holding you back. You may well find that that "something" is the inability of the car to rotate the rear at corner-entry, and then you have a solid target to hit.

[bluefirepony]

I hope you guys aren't laughing at me!

I doubt anyone is laughing..your questions are honest and deserve answers. I think Dave answered your general question about the spanish oak and tire roll pretty thouroughly, but ask if anything is unclear.

Sorry if I was not clear, but 275s are perfect for your car...my only reason for bringing it up the spanish oadk was that you looked like you were headed in the big wheel direction and I just wanted to make sure you knew about the impact of overall revs/mile on the performance of the car.

A couple years ago I happened upon a guy and some folks from a local performance shop who were scratching their heads on why the guy's $45k beauty with brand new supercharger, large arse wheels and a bunch of other bells and whistles kept choking and sputtering.

Basically the tire/rims were x% over the threshold and the computer thought something was awry and put the car in limp mode. I plugged my SCT in to make a quick fix for him but found out that the guy who tuned his car locked the tune ...lesson learned...or so I thought. A few months later I wrapped a set of 18" 5Zigens with some Yokohamas I wanted to test out and forgot to check the diameter. Got the car loaded, unloaded and gridded and hit the first turn when the car went flat....