Hoosier A7 tire size on flared car Options

[PlaysWithCars]

I've been running 225/45R15 on 7" and 8" wheels and they worked fine. But now that I need new tires I'm going to 8s all the way around and debating about stepping up to 245/40R15. Anyone have experience with 245 on 8" wheel? It's within spec from Hoosier for that tire and through email correspondence with Hoosier they said it would work fine. I also asked them about building heat in the tire since I struggle with that on the 225s already. They said that yeah I would build less heat but the cooler 245s would generate more grip than slightly warmer 225s.

[Charles Freeborn]

My car had 245's on 7" wheels on the rear when I bought. it. They barely fit inside of rivet on glass box flares. They required some goofy shimming with spacers, including an additional 6 or 8 mm on one side only, and there were still rub marks. Since going to 225's on all 4, on the 7's all's well.

[GregAmy]

Depends on the car, flares, and wheel offset.

I run 245/40-17 on 8" wheels up front and 225/45-17 on 7" wheels in back -- but this is on a 2500# Honda Civic Si Super Touring car.

What were the temps with your 225? How well did they fit your car?

From the info you've given us, then I can assure you that 245s will fit on an 8" wheel just fine. But will it work on your wheels on, your car, in your application, at your tracks? Testing, tuning, and tire temps is your friend.

First step: have the tire busters at the track save a 245 pull-off for you, have them mount it, then you check the fit on your car. Go from there.

BTW, I run 205 Nittos on 15x7 Panasports on my 914 historics car. Barely fit inside a "massaged" narrow-body car. 205/50-15 Hoosiers rub, 'causes there's a distinct difference between "205 millimeters" and "205 Hoosiers".

[PlaysWithCars]

The car is flared and by all measurements the 245s should fit. I've had 245s on 16s on the back of the car before and they fit fine. The bigger question is about 245s on 8" wheels and if ther are compromises to sidewall stiffness to consider. On my previous narrow body car I had 205 series Victoracers mounted on 5.5" wheels and they worked fine, but when I moved to 6" wheels and put the same tires on them they performed a lot better.

I reached out to Hoosier and to our local private tire mounter that installs tires for the local racing crowd. Both said that 245s on the 8" wheel will be fine because Hoosier has a stiff sidewall construction on the A7s; different that what I experienced with the Victoracers. They also said that I would benefit more from the additional rubber than I would loose from generating less heat in them.

Pulled the trigger and ordered 245s this morning. Will be confirming fitment in a couple of weeks and performance when it dries out here in the Pacific Northwest in August. (IMG:style_emoticons/default/dry.gif)

[Charles Freeborn]

Let me know if you make it to Portland.
I might get my 914 up toThe Ridge or possibly Pacific to run with SOVREN.

[PlaysWithCars]

Thanks for the input guys. I'll let you know how they fit soon.

Charles - why 7" wheels and not 8s? Are you class limited? Sorry, probably won't see you at Portland. I purposefully stay away from the track and focus on autocrossing for now. I know how much I would love the track but don't want to commit that much time or money right now. So, instead of dabbling and being dissatisfied that I'm not fully committed, I just stay away entirely. Drop me a note though if you make it up this way for a SOVERN event. I'd love to stop by, say "hi" and check out your car.

[Charles Freeborn]

7's are what I've got, and yes, 8's would draw too much attention in small bore vintage classes. Even the 7's are frowned upon. The Toyo RR's I have on those wheels seem to fit well and are fine for my purposes.
I've got a set of 6 / 7 Fuchs that have the additional inch inboard. I had a pair widened to the inside so I don't have to flare the rear fenders on my '74 911.
I also have stock 6 x 15 Fuchs that I can run if the scruiteneers really get fussy.
I've done some AX and it was fun, but bang for the buck there's more seat time at a DE. Plus the 911 is better suited for running flat out on a road course IMO.
Haven't tried the 914 at AX. That could be fun, but it's a bit of a process to get it warmed and ready (multiple coolers, lines, etc) so going through all of that for a 30 second run doesn't make a lot of sense to me.

[PlaysWithCars]

The 245s mounted up fine on the 8" wheels and don't appear to be "pinched" at all. The distance across the beads of the tires before they were mounted was right at 9" so I'm sure they would be happier with a wider wheel, but they seem fine on the 8s. Mounted on the car the sidewalls are very stable when you shake the car side to side. I think 8s will work.

On the car the rear is a tight fit with only about 1/4" clearance to the inner fender wall. the first autocross is tomorrow so we'll see if there are any rubbing witness marks after suspension articulation and sidewall flex at the event. I may need to add a small shim but there isn't a lot of room to outer fender lip, so if I have to shim, I'll have to get them 'just right'. On the front the extra 1" of wheel width is all to the outboard side and allowed the tire to fill out the fender nicely. Looks like I'll have plenty of clearance up front. But again, will be doing an inspection after the event to look for rub marks.

[PlaysWithCars]

[GregAmy]

We need some "like" and "heart" icons in this forum...

[ChrisFoley]

Watch out that the front tires don't hit the front corners of the fender as you turn the steering wheel. Sometimes the flares are finished and the airdam is attached in a way that leaves too much metal for a big tire to clear.

[PlaysWithCars]

Thanks for the heads up Chris. I noticed they were going to be tight in that area so I was able to do a slight trim and rounding of the corner to get good clearance.

Everything worked well and to my surprise, no rubs on the front and only a slight rub on the back between the tire and the inner fender well. I've added a 4mm spacer to the back and think that will be just about perfect. Except, now I need to put longer studs in the rear hubs as its not even flush with the top of the lug nut. (IMG:style_emoticons/default/headbang.gif)

[ClayPerrine]

Guys...

Thanks for the info on this. I am looking at getting some Hoosiers for the 4.0L car for using in AX. I have 16x8 design 90 rims to run them on, but I am concerned about them hitting in the front. I can adjust them with the spacers required to put the design 90 wheels on, so hopefully 245x45-16 A7s will fit.

Thanks

Clay

[914andy]

I would like to know if the 245 16's fit on the front on any width rim. I have not been able to do it with my GT clone

Andy

[PlaysWithCars]

Guys...

Thanks for the info on this. I am looking at getting some Hoosiers for the 4.0L car for using in AX. I have 16x8 design 90 rims to run them on, but I am concerned about them hitting in the front. I can adjust them with the spacers required to put the design 90 wheels on, so hopefully 245x45-16 A7s will fit.

Thanks

Clay

Unfortunately I would take my experience as directional only since I have fiberglass flares on the car and steel ones on the shelf still (IMG:style_emoticons/default/dry.gif)

To gain confidence that I could fit the 245R15 A7, I cut a disk the diameter of the tire out of a sheet of 3/4" plywood, drilled the bolt pattern in the center and bolted it to the spindle. Made it pretty easy to take measurements to all of the pertinent points with the weight of the car on the suspension. By measuring to the back side, the face of the plywood that was against the spindle, I was able to calculate where the tire edges would using wheel backspace and tire width.