What is the total tire diameter

[rchappelear 28]

I came across American Racing BLVD rims that i really like. I have been leaning toward a wide rear tire like a 18x10 or 18x9.5. The problem with the rims i like, they do not come with enough backspacing to fit (aprox 5.25 backspacing). I have seen alot of guys in here talk about a back spacing of around 6-6.25 in the rear for the wide tires.

So i was looking at their 20x10 with 6.1 backspacing (+15mm) and the 20x8.5 with 5 backspacing (+5mm) for the fronts. The new problem would be the tire diameter and fitting into our wheel wells with out major mods. I have seen post about a 26-27"dia tire is about max, but really hate the idea of a low side wall tire.

Do any of you have suggestions?

 

Sorry guys who hate 20" rims on the mustangs :)

Edited April 15, 2013 by rchappelear

[SELLERSRODSHOP 13]

i'm running 20x10 on the rear with 295/35 tires. no problems at all. they are 6.8" b.s. with 1/2" spacers to get them to 6.3" b.s.

 

 

 

Edited April 15, 2013 by SELLERSRODSHOP

[rchappelear 28]

Good fit! I take it those are the Boss 338 rims?

What is the room you have before you hit the fender lip and what is the room you have before you hit you leaf springs?

[rchappelear 28]

What I really want to do is this set up, but do not think i will have enough backspacing on the rear

18x8.5 5" backspacing (5mm offset) with 235/45/18

18xx9.5 5.3" backspacing (0mm offset) with 265/40/18 (honestly wish they were 18x10's)

 

Is 5.3" of backspacing going to be enough???

[Max Power 74]

i'm running 20x10 on the rear with 295/35 tires. no problems at all. they are 6.8" b.s. with 1/2" spacers to get them to 6.3" b.s.

 

 

 

 

That's a really great fit.

 

To the OP, if you hate the idea of short sidewall tires, why are you shopping for 20's?

[latoracing 256]

To figure out the tire dia. from the side wall spec, you have to do a little math, and it will get close to the actual tire dia. The easiest way is to have the tire there and measure the runout by wrapping a tape measure around the center of the tire. Then take your measurement and divide it by 3.1416.

The other way I do the math is, for instance, a 295-35-20. 295mm / 25.4 = 11.6142" (tread width) Aspect ratio 35 is the % of the tred width for the side wall height. 11.6142" x .35 = 4.065" Take that number, multiply by 2 (4.065 x 2 = 8.13") and add it to the wheel dia 20" + 8.13" = 28.13" in dia.

4" is a fairly good side wall, still is low compared to a 15" wheel, with a 28" tall tire. Hope this helps.

[rchappelear 28]

That's a really great fit.

 

To the OP, if you hate the idea of short sidewall tires, why are you shopping for 20's?

 

The 18's i like seem to lacking enough backspacing to work compared to the 20" rims backspacing. I am not apposed to short sidewalls, just timid on Really Short sidewalls.

[miketyler 15]

That wheel size makes that rear disc brake rotor seem tiny.

[Max Power 74]

To figure out the tire dia. from the side wall spec, you have to do a little math, and it will get close to the actual tire dia. The easiest way is to have the tire there and measure the runout by wrapping a tape measure around the center of the tire. Then take your measurement and divide it by 3.1416.

The other way I do the math is, for instance, a 295-35-20. 295mm / 25.4 = 11.6142" (tread width) Aspect ratio 35 is the % of the tred width for the side wall height. 11.6142" x .35 = 4.065" Take that number, multiply by 2 (4.065 x 2 = 8.13") and add it to the wheel dia 20" + 8.13" = 28.13" in dia.

4" is a fairly good side wall, still is low compared to a 15" wheel, with a 28" tall tire. Hope this helps.

 

Or just go to Tire Rack and look it up.....LOL!

 

The 18's i like seem to lacking enough backspacing to work compared to the 20" rims backspacing. I am not apposed to short sidewalls, just timid on Really Short sidewalls.

 

Fair enough....

[rchappelear 28]

So i wonder if i just purchase the 18x9.5 with 0mm offset and send them to a machine shop to remove material off the hub face to increase the offset. Do you think that is possible or would undermine the integrity of the rim

[SELLERSRODSHOP 13]

So i wonder if i just purchase the 18x9.5 with 0mm offset and send them to a machine shop to remove material off the hub face to increase the offset. Do you think that is possible or would undermine the integrity of the rim

 

 

to get the proper backspace from the specs you listed for the wheel above (5.3") you would need to get one full inch of material removed. I haven't seen many wheels with that much extra to spare.

 

try this first: do some research on those wheels. when I was in the market, I first found ridler, but the b.s. wouldn't work. I then ran across the boss 338's which were the exact same wheel & the b.s. worked on those. a couple weeks later, my dad purchased a set of foose wheels & they ended up being the exact same wheel too, again with different offsets available. 3 different brands, all the same wheel but b.s. available was different on all three. from what I hear, American racing gets many of their wheels made overseas. may end up finding the same wheel under a different name.