205 on 7.5" is going to be tight, but it should work.


Yeah, too tight for my tastes, but I spit out my recommendations for "safe" fitments. :) I cannot compensate for all combinations of wheels and tires out there - some will work and some will not.



-Ted

ReTed, how about a 215/50/16 on a 16x7.5 +40? Or are you saying that the tire needs to be narrower, like a 195/55 or 195/50?

That I would question if it'll fit.

Yeah, you get the picture.  The Turbo II uses a 205 wide tire stock, so try to keep with at least that size minimum.



-Ted

A 17 x 8 +40 isn't a problem...its the 225 tire thats the issue :) I wouldn't recommend that tire with that offset up front...a bit tight...

Okay, here's what I went with on my 16x7.5+40mm. I got Goodyear Eagle LS S1's ( please don't flame me, I'm not a race car driver ) 205/55/16's and I just took them out for a 100-mile stroll and everything seems fine. The tire guys said they'd work fine, too. I'll keep an eye on them, though. They look 10 times better than my 14's. Thanks everyone for your help.

Sorry, I had to up the brightness quite a bit. It's very cloudy out here today.

They're American Racing Vortecs.

https://www.rx7club.com/forum/attach...postid=2703285

https://www.rx7club.com/forum/attach...postid=2703306

Autopilot: they look nice and you'll have no problems with those sizes you went with....

England huh? cool!!!

Uh, NEW England, as in the eastern part of the USA.

ohhhh jeeez! sorry..

Great thread! I want to confirm what I believe will fit on my 87' Turbo FC. It has Tokico adjustables with Ground Control adjustable collars on it and camber caster plates. If a small range of offsets can be recommended, I can increase my choices for wheels. I want to run 235/40/17's all the way around on 8" wheels. Tires will initially be an old set of Yokohama A520's. When they wear out, I will probably go to Toyo Proxis Max Perf. tires. It sounds like up front I should be around 30mm to 35mm and at the rear, 25mm to 35mm. It sounds like the front will be the bigger issue so if their is a single offset I should stay with, please say so. I would like to offset to be the same front and rear so I can rotate if possible. I appreciate any and all recommendations. Thanks!

Shoot for +25 to +30.



-Ted

Many thanks Ted.

here some sites to save your souls:

offset calc:
http://toy4two.home.mindspring.com/offset.html

tire size calc:
http://www.miata.net/garage/tirecalc.html

My tires page...
http://fc3spro.com/TECH/MODS/RT/tires.htm
I have a comparison of tire sizes versus stock.

My rims page...
http://fc3spro.com/TECH/MODS/RT/rims.htm
I do have some info about rim recommended sizes and offsets.
Wheel spacer info on this page too.



-Ted

Would these fit on an fc? The front wheels are 18x9 with a 5.95" backspace (+24mm offset) and the rears are 18x10 with a 6.35" backspace (+22mm offset). If so, what tire would you recommend? If the rears are too big I could also get 18x9 there.

I doubt it.


-Ted

with the Corksport widebody fenders in front "they add 30mm width of clearance to the wheel well. "

What is the widest rim/tire I could run in front? I'd be using stock rear fenders, I'd like to get 255's in front and 275's out back...

I'd like to run 17's

I think your sizes are spot on...255's up front are whats on the RE-A white car

17" x 9" with a 255/40/17 will fit up front.
Offset?
+15 :)


-Ted

offset.......hmmm ya +30 - +20 sounds right to me... I think that white RE-A car has +35 or +32 on the RPF1 wheels... front. He might run spacers and or with longer studs...hard to tell.. which with a 5mm spacer would put you into the +30 - +25 ish area....

okay so after reading 6 pages-

88' - TII
Konis/GC

i want front 16 x 8 +25 with a 225/50
Rear 16 x 9 +32 with a 255/50 (unsure if offset is right)

This would clear a 1" drop right? This is what i had in mind?

I would personally go with 30 to low 30 offset...

That should work.
This is an excellent page for offset references...
http://toy4two.home.mindspring.com/offset.html



-Ted

Daaaamn...... for some reason i still need wheel&tire basics for dummies.....

i have (f) 17x7.5' w/ +40 offset 215/40 and
17x8.5 w/ +40 offset 235/40

My Question is can i go to a 225/45 (f) and 245/40 (r) ?
will i need spacers?

And seriously... if anyone knows of any site where this stuff is illustrated, let me know..... im feeling stupid

It's going to be too tight up front and back - wheels too far in.


-Ted

Okay, let me go into a small primer for this...

The stock FC3S turbo rims are 16" x 7" with a +40mm offset.
We can ignore the 16" wheel diameter for now.
What we concentrate on is the 7" width and +40mm offset.

Offset is how much difference from dead center.
So a 7" with 0 offset is a wheel that mounts in the center of the wheel.
We'll introduce the term "backspacing" - this is the amount of space from the back of the rim to the hub face.  With a 7" wide rim with 0 offset, the backspace is 3.5" - it's just 7" divided by 2 which is dead center.

To calculate backspace on stock rims, it's 7" divide by 2 and then ADD +40mm offset.  40mm is about 1.5".  3.5" + 1.5" = about 5" of backspacing.  As long as you keep all your aftermarket wheels with 5" of backspacing, it should clear the insides of the wheel well on your FC (up front).

http://toy4two.home.mindspring.com/offset.html
This site gives you a good idea on the relation between two different wheel dimensions.  Keep the original wheels specs as 7" and +40 for the stock FC turbo wheels.

Now, I realize this is a very general description of what's going on, and there are "fudge factors" involved.  The stock wheels can go in a tiny bit (like 5mm) before they get dangerously close to the inner suspension.  This and wheel nominal widths are all different, and this makes it not an exact science; keep in mind that the tires will usually hit before the wheel lip does.

The fronts are very tight with the stock size wheels and tires, so most of the above applies to the fronts only.


-Ted