BicuspiD

I have ordered my wheels, 18x8, +40 Front and 18X9 +38 Rear. It'll take 3 weeks to get them. The general consensus from the wheel and tire dealers and manufacturers I have talked to, for the "proper" tire size, is 235/40 in front and a 265/35 for the rears. By using this size tire, my overall diameters will be +.54" in front and +.44" in the rear (i.e.Taller) as well as 3.14" (Hmm pi....yummy) more contact patch on the rears and nearly an inch (.8) more in front OVER STOCK. With my Racing Beat springs and the proper offsets, I don't forsee the fitment being a problem, height or widthwise (Please let me know if I missed anything in my calcs).. Seems ideal for a street car with 18's IMHO BUT....

Currently on the stock rim I have 245/45-16 X4 . It seems by switching, I will have more contact patch in the rear (+.79 inches) , and a greatly increased sidewall stiffness, but is it worth the trade off of 40mm (-.78 inches) of front tread? It may be neccesary to not rub, but performance wise I can't figure out if its worth the trade... not to mention there is not an 'R' compound tire I can find in a 235/40-18 (Kumho Ecsta's are there for the rears, which will suffice, but I wanted Victoracers, not available in 18's..)

SOOOOOOO..

Is there a larger tire I can fit on an 18x8 +40 that won't rub, with my current springs (RB) and no rolling/cutting?
245/35-18 ?

Is there a "staggered" setup, 17's on front that works well? maybe a 225/45-17?

On the fronts, rather than run a 235/40 S03 or something, wouldn't a 225/40 'R' Compound tire be much more responsive?




The car is mainly autocross and street driven, and will be assuming racetrack duty soon as well. I plan on getting some Fikses for when I graduate to track duty.

Thanks in advance for any insight you can give me. heh last RX-7 I put tires on was my 82 (205/60-13 baby)




Richard
93 MBM Touring

PS Anyone that was interested in the Gram Light Pro wheels from Rays go ahead and PM me. I am getting together a container order.

SleepR1

I would put 225/40-18s on the 8 x 18 fronts and 255/35-18s on the 9 x 18 rears. The overall diamters are 25 inches fr/rr, same as stock 225/50-16 tires. Tire widths will fit nicely on your rims. Rim coverage will be 90% of the tire section width which generally is the best for performance driving, road or track.

I wouldn't mess with an extra set of wheels from Fikse just yet. Get out on the track with your road setup, and see what that's like. Once you begin overdriving your road tires and brake pads...THEN begin thinking about a separate setup...