txsilverado

Ok, What is the biggest/widest size wheel/tire combo that I can fit on my 72 BB coupe? I don't want to modify the suspension at all. I was hoping to go with the TT D's. The gray, raw cast faced looking American Racing wheels. It is very important that the info I get is correct, as I am most likely going to mail order the wheel/tire combo and don't want to have to return them because of fitment problems.

Thanks a bunch!

txsilverado

Anyone??

GrandSportC3

I'd say about 15 x 8.5 wheels with about 3.5 inch backspacing and 275/60R15 tires in the rear and 255/60R15 in front. The 255's might rub in front with the stock 4 inch backspacing but with about 3.5 - 3.75 inch backspacing they should clear without rubbing. The 275's in rear will rub against the e-brake bracket with 4 inch backspacing but will clear with 3.5 inch backspacing.. Relocating the bracket is easy. If you don't weld yourself, any weld shop should be able to cut off and relocate the bracket for a few bucks..

CCrane65

I'm running 255 x 60 x 15 Firehawk Indy 500s on factory rally wheels and they do rub a bit on tight turns in the front. No issues in the back.

cc

txsilverado

Crud! I was hoping to step up to at least 16's.

GrandSportC3

taller wheels will work. It's only the width that is limited.. There's no limit on wheel height as long as the wheel&tire combo is less than 30 inches tall..

txsilverado

Ok. following your logic, I can go with 16x8.5 wheels with 3.5 inch back spacing. So, what size tire should I run if I want to fill out the wheel wells in width, and keep close to stock height of the wheel/tire combo?

cchristo

Try doing a forum search using terms such as "tire size" "wheel size" "tire combination" "largest tire" and similar terms. You will find hundreds of posts that answer your question.

Make sure you use the quotation marks to do a more accurate search.

FYI, you can run larger than 16".

Scooter_boy

Well I guess all those years in a tire store back when we had to go to class on this stuff may have paid off... so here's lesson # 1

a little math... and some facts about how tires are NOW sized...
the first # ie 225 = width in mm
second # /70 = aspect ratio or % of sidewall height to width
so stock has a 157.5 mm tall sidewall
if we multiply the sidewall height X 2 (since there is a sidewall both below and above the rim in our overall height = 315 and convert it to english X 25.4 = 12.4" + the diameter of our rim 15" we get a 27.4" tall tire.
you can do the same for each tire size.

after all that, I found a site that has it all ... http://www.tirerack.com/tires/tirete...e.jsp?techid=7

all of the tires below should fit ok except the 295/50R16 because of it's width. Most of them will not even make much of a change in your speedometer and most will look like they fill the fender lines much like the stock ones do because they are all about the same diameter.

stock size = 205/75R15 width is 205 mm or 8.2" & dia is 27.1"
plus 0 size = 225/70R15 width is 225 mm or 8.9" & dia is 27.3
plus 0 size = 255/60R15 width is 255 mm or 10" & dia is 27.1" that's what I am running on stock rims all the way arround.
plus 1 size = 275/50R16 width is 275 mm or 10.8" & dia is 26.8"
(I don't know of a 275/50R16 closest is a 295/50R16)
so a size 295/50R16 has width of 295 mm or 11.6" & dia is 27.6"
plus 2 size = 235/55R17 width is 235 mm or 9.25" & dia is 27.2"
plus 3 size = 275/40R18 width is 275 or 10.8" & dia is 26.6"

as you increase the rim size the sidewall decreases in size but the goal is to keep as close to the original overall diameter as you can. When you see one that doesn't, you will usually be able to spot it...

again after the fact, I found this site... http://www.tirerack.com/wheels/resul...&autoYear=1972

my72vette454

This place will figgure out about anything you might want to know about tire sizes, rear end ratios, rpms, mph, ect

http://www.angelfire.com/fl4/pontiacdude428/Hot.html

Kap142

Not the biggest but I run 235/60r15's in a Dunlop Radial Qualfier on my 72 BB. I love the look and they're are huggers.

Ken