Track Tires

[NJS]

Hoosier recently released new 20" tire sizes, that might just fit the NFGT:

Front: 265/30ZR20 compared to 245/35R20 OE
Rear: 335/25ZR20 compared to 325/30R20 OE

Thoughts?

Worried that the additional width (especially up front) may cause fender rub in Track mode, even with the shorter sidewall....

 

[Jason Watt]

Interesting...
Are those slickk tires?

 

[stuntman]

Hoosiers run WIIIIIIDE. So I wouldn't bet on it. What's wrong with the Cup 2s?

 

[ChipBeck]

Hoosier recently released new 20" tire sizes, that might just fit the NFGT:

Front: 265/30ZR20 compared to 245/35R20 OE
Rear: 335/25ZR20 compared to 325/30R20 OE

Thoughts?......

Only one way to find out. Size is so close I bet they’ll be fine. Therefore I’m officially tasking you the assignment of buying and mounting a set. Use them agressively on the track and report back here. You might give Hoosier a call and see if they have already tried them on a GT.

Chip

 

[STORMCAT]

Hoosier recently released new 20" tire sizes, that might just fit the NFGT:

Front: 265/30ZR20 compared to 245/35R20 OE
Rear: 335/25ZR20 compared to 325/30R20 OE

Thoughts?

Worried that the additional width (especially up front) may cause fender rub in Track mode, even with the shorter sidewall....

Interesting , will need to look at all of the specs , cross sectional width etc. OD is critical so not to mess with ABS algorithms etc..

I can say this. when I worked with the ADV-1 wheel guys foe SEMA they wanted to go wider . They took lazer scans and I did it old school way. Adding 5mm to the each side of the rear tires shouldn't be a problem if the OD is the same. there was 3/8" clearance on the front side and a little more on the back side . Adding 10 mm to each side of the front tires would really need a closer look at the OD and cross sectional width.

I dropped my can in Vamax mode and made clay impressions of the gaps.. .. :biggrin

 

[STORMCAT]

Hoosiers run WIIIIIIDE. So I wouldn't bet on it. What's wrong with the Cup 2s?

The cup 2's are realy good.. Hoosiers would probably be stickier when hot.. If the Hoosiers are lighter that would also add to their appeal..

 

[Ed Sims]

Interesting...Are those slickk tires?

If they are the Hoosier A7 then they are DOT approved road race tires. There is no tread, only some grooves to measure wear. Some of us have run the A7s on our '05-06 cars for the road & track. They probably are less expensive than the OEM Cup 2 tires but comparable, or better, in performance on the track.

Ed

 

[STORMCAT]

If they are the Hoosier A7 then they are DOT approved road race tires. There is no tread, only some grooves to measure wear. Some of us have run the A7s on our '05-06 cars for the road & track. They probably are less expensive than the OEM Cup 2 tires but comparable, or better, in performance on the track.

Ed

I think he wants to say R7's :biggrin

 

[stuntman]

The cup 2's are realy good.. Hoosiers would probably be stickier when hot.. If the Hoosiers are lighter that would also add to their appeal..

I doubt they are lighter than the Cup 2's. Michelin makes very light tires.

 

[ChipBeck]

I doubt they are lighter than the Cup 2's. Michelin makes very light tires.

This seems to be the case. A Bridgestone rear tire for the ‘06 GT weighs 35 lbs while a Hoosier rear tire weighs 31 lbs. A Dunlap rear tire for the new GT weighs 37 lbs and the Michelin rear only weighs 31 lbs. A 20” Hoosier R7 rear can’t weigh much less than 31 lbs.

Chip

 

[stuntman]

B-stones are usually heavy. Not good for rotational inertia, gyroscopic effect, unsprung weight, etc... Tire weight matters.

 

[Ed Sims]

I think he wants to say R7's :biggrin

I should have said A7 or R7. Technically the A7 is stickier for Autocross while the R is for Road Race but I have run the A7s on my GT.

Ed

 

[GTED]

Ed, you put A on the GT? I put R on my GT. Wouldn't A heats up too early and could get overheated on track for a 3500lb car? I put A on my Ariel Atom for track because the car is too light and I have hard time getting the tires up to temp, especially the fronts.

Ed

I should have said A7 or R7. Technically the A7 is stickier for Autocross while the R is for Road Race but I have run the A7s on my GT.

Ed

 

[stuntman]

Ed, you put A on the GT? I put R on my GT. Wouldn't A heats up too early and could get overheated on track for a 3500lb car? I put A on my Ariel Atom for track because the car is too light and I have hard time getting the tires up to temp, especially the fronts.

Ed

Measure the temps. If they're not getting outside their temp window, then As will be faster than Rs.

 

[NJS]

+1 The A's are faster than the R's even on the heavier Mustang. They just don't last as long :facepalm:

 

[Ed Sims]

My A7s worked fine on the road track. No heating issues. Great tires!

Ed

 

[BtwoG]

Back when I was racing my Mustang a 315/35/17 Hoosier was about 4 pounds lighter than the same size Kumho. I was shocked there was that much of a difference. I could have believed a pound, but 4 pounds is alot.

When the majority of time trial racers switched to A6s, NASA shortened the sessions from 20 minutes to 15 minutes because they would lose grip after about 10 minutes.

 

[DJC]

If the tire size holds true. The calculations show the fronts are 0.78" wider, but 0.5" less in height. Rears are only 0.39" wider but 1.08" less in height so they my not be an issue.

I've been trying to find an alternative for track use so if anyone tries this please keep us informed.

 

[DJC]

Just got off the phone with Hoosier. They are planning on a few more sizes. One matches the OE front tire. This may help. Nothing an exact match for the rears.