I'm looking at getting a set of wheels and tires strictly for drag racing. I'm looking at the Bart IMCA Comp Wheels from Summit. They come in a 15X8 with backspacing from 2"-5". What size backspacing will I need for an FD? Looking at slapping on some Nitto Drags 275/50/15. Is there any other tires I should be looking at? Thanks ahead for any info.

 

yeah and what about backspacing for FC guys tooo


how do you convert off set to back spacing?

 

ok for FD this is what I think...

stock wheel is 16 8 +50
to convert +50 offset to backspacing

(8 / 2) + ( 50 / 25.4) = 5.9" of backspacing
looks like your going to need a spacer to run these wheel on FD

I dont know how much extra room FD have so maybe someone can shed some light on it.



for FC

16 x 7 +40 ( 5" backspacing ) (7/2)+(40/25.4)=5

to run 16X8 on FC and keep 5 inch back spacing
(.5*25.4) 12.7 40-12.7= +27.3 offset

but becuase there is room in the rear of FC
you can cut that in half so 40-6.23 = +33 offset
so +33 - +35 offset should fit in the rear with no problem

 

By your calculations an 8" wheel with 5" of backspacing will only yield 1" of offset or 25.4mm
offset=5-(8/2)

Lots of 10" wheels with 50mm offsets work fine on the FD
Backspacing=1.97"+(10/2)=6.97"

I'm assuming that FD's will be more than fine with a wheels with these specs. The math seems to work. Let me know if I'm on the right track.

Got most of my info here:

http://www.scuderiaciriani.com/rx7/wheels.html#OFF

 

a 10" wheel with +50 offset would be
(10/2) + (50/ 25.4) is 6.9 inches of back spacing

its the same forumal I used to calc stock FD wheels
and come out with 5.9 back spacing.

 

So wouldn't 5" of backspacing be even further away from rubbing than 5.9"? I would think that the limiting factor that I should be concerned with is the front spacing. The 5" backspacing will leave me with about 3" of front spacing. Since the 10" wheels with the 6.97" of backspacing also have about 3" of front spacing, I should be golden. What do you think? Is my reasoning valid?