333pg333

http://www.worldtimeattack.com/

I am gearing up to run in an event that is starting to build some decent momentum and following down here. It's the largest Time Attack in the world apparently and has cars coming from the US, Japan, and NZ, as well as some local content. I know this isn't quite the style that is so popular in this forum however I'd like some opinions as to an issue I'm faced with.

Firstly we are required to run R spec rubber from a restricted list. Many of these tyres are not available in the US as you guys tend to run Hoosiers R6s or full slicks. (While the R6s and similar tyres are DOT compliant, they're seldom allowed in our events down here.)

While I can't ask many of you your opinions on the actual tyres in the list below, I wanted to gauge opinions on what I should do with the issue I'm faced with.

Namely, I want to run the Nitto NT01 on my car and that I want to run the 315x18" on 11.5" rears but I'm also going to try and run them on my 10.5" fronts. Stay with me, our front engined cars work well with a square setup but obviously it's not ideal to have a 315 on a 10.5" rim. They are in fact the wheel and tyre in my avatar. I've had one of them mounted and it looks to have a little bit of sidewall bulge which might cause them to overheat excessively and roll around too much on the wheel. Not massive, but visible. To add to this we mightn't be able to fit it under the wider fender that is going on. So that part of the issue may be taken out of the equation anyway. Unfortunately in what I suspect is due to a deal they've done or an instruction they've received from Toyo, the next size down in their lineup is a 275x18" which is too much of a stagger So, I am contemplating using a different brand of tyre up front in a 295 or 305 size. There is a Toyo RA1 in a 305x18"...but with a 35 profile it's 1" taller than the Nitto and I don't think this is a great idea? It's a shame as I believe the compound of the RA1 and the NT01 is meant to be similar or even the same.

Also, these are are Sprint events, not endurance, so perhaps I could run the 315s up front (provided they fit)? There's actually not many brands that carry a 315 in R spec. Of the brands listed that I know you US guys will be familiar with, there is a Kuhmo Ecsta V700 in a 305/30x18 which would give a similar OD to the Nitto, but I don't believe these enjoy a great reputation around here?
There are also the MPSCs but I need these tyres to get to heat pretty fast and my car will weigh in the 2550-2650lb region and I believe that these tyres suit heavier cars. Then there's also the option of running a different brand, say the Dunlop DZ03s, at 295s all round to maintain a square setup. On top of all of this will be the fact that I won't have a lot of time before the event to shake the car down and there will be a LOT of new components on the car to deal with.

So all in all, what should I do?

Manufacturer Tyre
Yokohama/Advan A048R, AO50R
Bridgestone RE540S, RE55, RE-11S
Dunlop Formula R (D83J, D93J, D01J, DZ02G, DZ03G)
Federal 595RSR, FZ201
Kumho Ecsta V700, V70A
Michelin Pilot Sport Cup, TB15
Pirelli P Zero C, P Zero Corsa
Silverstone FTZ Sport Tyre RR, S575, S585
Toyo Proxes RA-1, Proxes R888, Trampio R881
Hankook Ventus Z221
Nitto NT01

J richard

I love the nittos. I don't understand why you would be thinking you have an issue with a loading on the tire. I've run 275-295s on the back of a 964, which has more static weight on it than the front of a 951 and it's doing ALL the work on a rear engined/rear drive car. And they worked flawlessly. If you go 315s I wouldn't hesitate. We run 225 RA1 on the 944 spec cars at similar weights 2650+ and they are plenty of tire for the chassis, so with the added envelope of a TA car a ra1 would work fine as well. I have been told by a toyo rep that the NT01 uses the compound of the RA1 with the carcass design of the r888, so it is the better tire. Can you run Hoosier A6?

333pg333

No, I have no fear of running the 315/30s on the rears, it's just that I want to run them on the fronts as well, but on only a 10.5" wheel. Therefore we're getting a little bit of visible sidewall bulge not even on the car yet. So my concern was having too large a tyre for the wheel and it being overloaded in terms of heat build-up.

Another concern was running the 305/35 RA1 on the fronts but them being a 26.3" tyre vs the Nitto that is a 25.3" tyre.

Yet another thing that I forgot to mention is even if we can fit the 315 up front it may mean that I have to run less caster due to running out of physical space the further forward the tyre is moved.

No, as you can see in that list. No Hoosiers. There would be a huge market for them worldwide if they made an actual road legal R spec tyre to compete against others out there. For the rest of the world we generally are not allowed to run Hoosier R6s (or similar '2 liners') in events unless you wish to sub them instead of a full slick. Many forms of motorsport don't allow full slicks.

Anyone have an opinion of the Kuhmos V700s in comparison to say the RA1s? Also bear in mind that often we are only out for ~10 laps in events like these. They're not dissimilar to F1 qualifying in essence.


Perhaps I should make it a poll...but I'm thinking my choices here are as follows:

1) Providing they fit inside the widened fender, run the Nitto 315s all round at the risk of overheating the tyre and losing some caster.

2) Run a 275 Nitto on the front at the risk of too much understeer (likely to be exacerbated by incoming twin element wing).

3) Run a 305 RA1 on the front that is likely same compound as Nitto...but it's 1" taller tyre. Although I assume that this would really only be 1/2" taller in real terms as it's divided by the axis, yes?

4) Run a different brand on the front either a 305 Kumho V700 or a 295 Dunlop, Bridgestone R spec and hope to make it balanced.

5) Run a different brand all round that is matched front to rear but smaller overall footprint. Car should be approx 2600lbs with ~500hp and a decent amount of downforce.

Eric_k

I've seen the 315 NT01 used on a 10 inch rim. 10.5 is within spec for the 315 according to Nitto.
http://www.nittotire.com/functions/t....asp?tire=nt01

It should be fine if you can get it to fit the car.

d15b7

hi.

definitely the Nitto NT-01. i drive several cars for clients here in the US at the bigger T/A events. in the class we run, the requirements are for treadwear greater than 50; we have run various tires, and the NT-01 is the superior tire (pretty much all of the top teams agree; the NT-01 is what we see as the most common tire amongst the winning teams).

I primarily drive prepped Mitsu EVOs, on which we run a 275 width tire all the way around on a 17" or sometimes 18" rim, so i don't have a lot of input concerning your question about width vs tire size. but as for the tire, i'd try and go for the Nitto. good luck!

Todd
ReidSpeed

PS i will be doing several of the Time Attacks here; the new Global T/A, plus Realtime T/A.

rlm328

NT01

J richard

Gotcha, didn't think that was the "official" list, the A/R6 is the preferred Dot R.


While not ideal the 10.5 rim is in the approved widths, so unless you are going to be generating some huge downforce it should be fine. I think id take some potential sidewall roll over mixing brand/type. You could but without testing you dont know how they will go off differently over time, HC out or even how they behave with temp/pressures.

Of the others on the list I've heard good things of the hankooks but no direct experience, ive run the Khumos the tire to have is the 710 the victoracers are not in the same league. I'd do the nittos and live with the bulge or go down to the 275 and adjust for the stagger.

333pg333

Thanks for the input guys. This was my preferred route if we could get them to fit. I am still concerned a little over possibly losing some caster but we can modify the bodywork as much as possible and perhaps play with the camber plates in terms of repositioning the slot rather than side to side.