Wheels/Tires for autocross, 1988 Mazda RX-7 Turbo II.

So, as my elder son gets closer to getting his license, the topic of autocrossing the RX-7 comes up with some frequency.  While it currently  has a little extra boost, modified turbo, Haltech ECU, upgraded fuel pump and secondary injectors, water/methanol injection, and freed-up intake and exhaust, it's still running a bone-stock suspension and has some antique Yokohamas on the front and Hoosier drag radials on the back.

New tires will need to be "streetable," but to me that basically means better on the street than the drag radials on it now.

Budget is as close to zero as possible, but I'm hoping we can get it done for about a grand.  Likely source is Tire Rack.

So, what's the best way to go here?  TIA!

For his first AutoX efforts I'd argue you need any old "tires." I'd be tempted to target Craigslist first in roughly OEM size. In his second year target hitting tire rack for something with some grip.

Federal 595 super steels. Should be able to get a set stock size for under four hundred bucks and will do just fine for a first couple of years on the cross

Hot tip - SN95/New Edge Mustang wheels are the perfect offset for FC RX-7's. Get some take-offs from a 94-04 and hit the course.

I like Javelin's idea. Back in the day I had a set of 16" Mustang wheels on my TII. Lighter, wider, sat out a little more, looked better and most importantly the price was right.

Hmmm.  Mustang wheels.  I am liking that idea.  For a car that used a fair bit of aluminum, especially for back in the day, to save weight, the TII wheels are improbably, shockingly heavy.  I think I weighed one wheel and tire and it came it at 46 pounds.

I get the "any old tires" thing, but I don't want to do this again in a year.  This kid will be a prodigy.  He's been driving go-karts at G-Force since he was 8 years old.  Since he's moved up to the adult karts, he can beat me about as often as I beat him.

These come with some Eagle F1's.  I'm guessing the Cobra wheels are too wide, though?

https://fredericksburg.craigslist.org/pts/d/fredericksburg-mustang-cobra-wheels/6893321412.html

That one picture looks pretty broken also.

Cobra wheels are 17x9, those will fit fine in the rear, will likely fit the front with a bit of clearance adjustments depending on how low you are. I'd lowball him to $200, get rid of the tires, and slap some Bridgestone RE71R's on there and let the kid rip.

I just remembered something from 16 years ago: The OEM Mustang tires are a bit taller than stock and cut into the front fenders at the track with OEM suspension. The FC has a lot of body roll. Sounds like he knows what he's doing, but the car is not going to be classed competitively, perhaps you should put the wheel savings into a set of sway bars?

+1 on the Bridgestone Re71s. If you are hell bent on the price and want a little less grip, then the Firestone Indy 500 made be the best option. I got some for a crown vic after hearing only good things about the tires.

There are a bunch of wheels from other cars that fit the FC. If you want cheap 15s the Jeep Cherokee's should fit and early 2000s Maxima wheels will fit, I think they were 16s but my be 15. There is a website I found that you could search by bolt pattern and they listed offsets and center bores also. Try roadkillcustoms.com they might be able to give more choices of other vehicles that use the same size wheel. My 15" BBS wheels only weigh 14 pounds if you can find a set of them. 

In reply to Javelin :

17x9 would be an awfully tight squeeze on the front. I'm running 17x8 et35 wheels wrapped in 225 Falkens with a 6mm spacer on mine and I really wouldn't be comfortable running much less clearance to either the strut/spring or the fender.

imgon said:

There are a bunch of wheels from other cars that fit the FC. If you want cheap 15s the Jeep Cherokee's should fit and early 2000s Maxima wheels will fit, I think they were 16s but my be 15. There is a website I found that you could search by bolt pattern and they listed offsets and center bores also. Try roadkillcustoms.com they might be able to give more choices of other vehicles that use the same size wheel. My 15" BBS wheels only weigh 14 pounds if you can find a set of them. 

When we first started running at the strip, I got a pair of Maxima wheels from the pick and pull and put some BFG drag radials on them.  They were the 9-spoke 15's, and skinny, maybe 6"?  As the car got faster, we started exceeding redline in 4th at the big end, so I put the Hoosiers on the 16" stock rims to get a bigger O.D.

I'm kinda thinking 17 x 8, but I'm pretty flexible. 

Jeep wheels are fairly light, wide, and offer a pretty good tire selection.

I recommend 225 45 15 hankook rs4 on jeep lace wheels.

The rs4 are super grippy and wear like iron.

1988RedT2 said:

imgon said:

There are a bunch of wheels from other cars that fit the FC. If you want cheap 15s the Jeep Cherokee's should fit and early 2000s Maxima wheels will fit, I think they were 16s but my be 15. There is a website I found that you could search by bolt pattern and they listed offsets and center bores also. Try roadkillcustoms.com they might be able to give more choices of other vehicles that use the same size wheel. My 15" BBS wheels only weigh 14 pounds if you can find a set of them. 

When we first started running at the strip, I got a pair of Maxima wheels from the pick and pull and put some BFG drag radials on them.  They were the 9-spoke 15's, and skinny, maybe 6"?  As the car got faster, we started exceeding redline in 4th at the big end, so I put the Hoosiers on the 16" stock rims to get a bigger O.D.

I'm kinda thinking 17 x 8, but I'm pretty flexible. 

17 x8 will raise the car an inch.  We have experimented with both 15s and 17s on rx7s.  15s are always faster (unless a particular track favors a lack of shifting as you found out at the strip).

wvumtnbkr said:

 

17 x8 will raise the car an inch.  We have experimented with both 15s and 17s on rx7s.  15s are always faster (unless a particular track favors a lack of shifting as you found out at the strip).

Good point, but I remember the Maxima wheels looked pretty small on the car.  Let's not forget that a 16-year old will be very concerned with how the car looks. 

Maybe I can find a 16 x 7 that's lighter than the OEM's?

I think that 16" wheels are the oddball, can't find good tires at a good price size.

Three options: Find a set a set of convertible 15" BBS wheels and the widest tires you can fit on them.

Get the 17x8 Mustang wheels and run lower profile tire on them to keep the ride height about stock.

Or other 17" wheels. I think the 17x7 Miata wheels would fit on there, too. This set is $300 with tires in Raleigh.

Despite his experience in karts, learning how the clutch LSD in that car is going to operate might be a good idea.  I know the first time I wound up pointing the way I was coming from surprised me. Maybe use the tires on there now and let him do some turns in a parking lot to understand how it will corner under load.



 

In reply to Brett_Murphy :

NC MIata wheels are waaaay too high offset to work.

Maybe a 10mm difference, which is a small wheel spacer.

In fact, I think some of the NC and FC wheels share a 48mm offset, but the NC wheels are 7.5" width instead of 7".

 

I still say go with rs4 tires.  

For my old FC I had 17x8 Mustang wheels with 225/45/17 tires, which BTW are within a few % of stock OD and fit without any rubbing. For the track I used some custom 15x9's with 225/45/15's. Now that there's some selection in 245/40/15's, I'd be looking into those more seriously. The smaller diameter gives you free lowering and a shorter final drive.

I ran BFG Sport Comp 2s (UHM summer, 340 treadwear) on the street and autocross, and while not as grippy as the Rival S, they did pretty darn well.  I bought them because they were available at a great price from Costco, Tire Rack has yours for $106. 

I currently run Hankook Ventus V12 evo2 XL,(max summer, 320 treadwear) again because of the great price from Tire Rack, $90 each in your OEM size. I have yet to get them to squeal on the street, and I think they could handle an occasional autocross well. 

No experience with the Firehawks, but they are  $11 more than the Hankooks and a 340 treadwear. 

If you go for a dedicated autocross tire, I have run the Rival S and the RE71 and so far, I like the Bridgestones better.  

Brett_Murphy said:

I think that 16" wheels are the oddball, can't find good tires at a good price size.

Yeah don't get 16s, tire selection in that diameter is garbage. Go for 15s or 17s.

RE71Rs would be the best tires, but since he's just started driving, that's not necessary and maybe not helpful. You could save money with Indy 500s or Westlake RSes, or RS4s if you want to pay more for longevity.

I thought 16" tires were being phased out as well, but but tire rack lists seven 200tw tires in 205/55/16, including RE-71, RS-4, ZIII. In 225/50/16 there are eleven options. There are two options in 215/45/16.

Anybody know what size these are?

https://richmond.craigslist.org/wto/d/richmond-mustang-wheels/6882373782.html