tire size??

[69fstback 10]

What is the biggest size i can run out back with a 15X8 with 4.5 backspacing? I was thinking a 255/60/15 may be a good choice or a 275/60/15. Looking for the right stance just a tad higher in the back opinons also. Thanks

[Burn 14]

I've been wondering the same and I think 295/50/15 is the widest on a 15x8 w/4.5 BS. See the Blue Mach 1 below. I think they look good, but a little too big for my taste.

 

I've decided to go 275/50/15's Rear and 235/60/15 on the front. I might change the fronts to 225/60's because I want a slight rake with the rear a little taller. I'm also going with 1" drop front coil springs up front and grab-a-track 4.5 leaf, mid eye (1" lower) on the rear. Hopefully it will look okay. I’ll be running Wheel Vintiques 54 Series Magnum 500’s 15x7 w/4.25 BS and 15x8 w/4.5 BS.

 

I haven't found anyone running my combo. Bnickle used to run these tires, but not on a fastback and not a 1" drop, so his look and clearance would be a little different.

 

 

The pix's below were cars on ebay. I contacted the seller to see what size wheel/tire combo they were running.

 

Boss 302 has 15x8's 255/60/15 (rear) and 15x7 245/60/15 (fronts) Car looks lowered 1 to 2.5 inches.

 

The Gold Mach1 has 255/60/15 rears and 235/60/15 fronts. No motor in the car, so it sits high. Should be a 428ci.

 

The Blue Mach 1 has 295/50/15 rear (that’s right 50's) and 235/60/15's front. Looks like stock suspension w/351w.

 

Coz is running 275/60/15's 15x8 and 225/70/15's 15x7s. I think he's running air shocks on the rear, so I don’t know if they are needed or not for clearance.

 

Let us know what you decide.

 

Here is a cool tire size chart I found for the Old School BFGoodrich Radial T/A’s.

http://www.buicks.net/shop/reference/tires.html

[69fstback 10]

The 295's look kinda cool I think i may go with a 275/60/15 That looks to be abotu right for a nice size tire and a 351W. I may go with a smaller tire in front also i have the 1 inch drop already done when i got the car 5 years ago. I like the back alittle bit higher also

[cphsonic 11]

Kinda wondering about the 4,5" BS on an 8" rim with 295? I run 18x10 with 6.4" BS with 295/35/18 and that's absolutely perfect, barely (not) touching the fender or frame/inner fender. Your setup will rub the fender lip, rolled or not... :blink:

[70vert 17]

I would second that. On my 17x9, 5.5bs wheels they seem just about perfectly centered, maaaybe could go in .5" on each side, and a 275/40/17 fits fine. 9" rim, 5.5bs = 8" rim, 5"bs. A 4.5 would be out farther.

 

You could always get a custom shortened crate rear from Currie! :whistling::biggrin:

 

Kinda wondering about the 4,5" BS on an 8" rim with 295? I run 18x10 with 6.4" BS with 295/35/18 and that's absolutely perfect, barely (not) touching the fender or frame/inner fender. Your setup will rub the fender lip, rolled or not... :blink:

[Burn 14]

Kinda wondering about the 4,5" BS on an 8" rim with 295? I run 18x10 with 6.4" BS with 295/35/18 and that's absolutely perfect, barely (not) touching the fender or frame/inner fender. Your setup will rub the fender lip, rolled or not... :blink:

What setup will rub?

[jgstang 21]

on my 69 vert i'm going with 17X9 5.95 bs 275 or 285 40's rear but the front i'm not sure now because the rim guy can only get me 17X8 5.70 bs ? i wanted to run 245-40 on the front but will this b-spacing screw me up on the front now? this car is lowered 2" this rim/tire business is driveing me nuts trying to get it just perfect! Jim

[69fstback 10]

you guys think a 275/60/15 will rub on a 15x8 with 4.5 backspacing? Should i go with a 5.5 backspacing?

[cphsonic 11]

It would rub or come very close I think. 5" BS would be perfect for an 8". Normal BS for a 9" is 5,5".

[69fstback 10]

OK so i would need a 15x8 with 5 inch backspacing to get a 275/60/15 under the car and look good? Thanks guys

[coz 108]

you guys think a 275/60/15 will rub on a 15x8 with 4.5 backspacing? Should i go with a 5.5 backspacing?

 

This has been kicked around in several different threads over the past couple of months.... 275/60/15 on a 15x8 rim with 4.5bs fits perfect. I have that exact setup and once I ditched the crappy air shocks I had no problems. Never had a rubbing issue inside or outside but with the air shocks the rear would bottom out and the un-rolled fender well would catch the sidewall. I went to 4.5 leafs and KYBs and have not had any problems.

 

One inch "clearance" inside and outside...

 

http://www.1969stang.com/gallery/COZ-69Mach1/114_1412?full=1

[Boogerschnot 12]

What about on a coupe.. Im going to run 225 60 15's on front with 4.25 b/s and 255 60 15's on rear with an 8 inch rim and 4.5 b/s See any problems? Could I get that 275 under the rear?

 

My rear is dropped an inch with 4.5 leafs and KYB'S

[coz 108]

What about on a coupe.. Im going to run 225 60 15's on front with 4.25 b/s and 255 60 15's on rear with an 8 inch rim and 4.5 b/s See any problems? Could I get that 275 under the rear?

 

My rear is dropped an inch with 4.5 leafs and KYB'S

 

That's a good question... I should state mine is a Mach (duh - in sig). I would assume the same but assuming will get you.....

 

As to the 225/60 ~ 255/60 combo check tire height front to back. You don't want the front tires taller than the back. I like a neutral stance - some like the door stop / jacked up look. In my sig it's 225/70/15 in front and 275/60/15 in the rear. The back tires are .6" taller or .3" from the centerline.

 

So you have 4.5 mid eye springs? Mine are standard eyes so I have close to a standard ride height.

 

You know - when I was shopping rear tires I asked the dealer to mount 255/60/15's and I drove around for 10 miles. Didn't like the rake so I had him swap them for 275/60/15. Get a good tire dealer and have him order both sets. You might have to pay for mounting twice but that's a small price to pay. I've heard alot of car builders bitch that the two toughest things to please the customer are tire size and paint color. We are visual animals....

[Boogerschnot 12]

Thats what Im afraid of.. That the 8 inch wheel will bring the 255 tire height down too much and the rear will be shorter... But If that seems to be the problem I could just keep with the 7 inch wheel all around.. I dont think It will matter that much.. I just think its the fact of having an 8 inch wheel in the back that would make me happy inside..

[Mace 10]

Hey Coz,

 

I was going through your photo album. You have a very nice looking wife, and some beautiful daughters!

 

 

Hehehe

[coz 108]

I have some more pics when they started taking off the clothes. It was an interesting day to say the least. At one point there were 3 girls dancing naked on a lift. The rod shop that sponsored the show knew how to bring the guys in.

[coz 108]

Thats what Im afraid of.. That the 8 inch wheel will bring the 255 tire height down too much and the rear will be shorter... But If that seems to be the problem I could just keep with the 7 inch wheel all around.. I dont think It will matter that much.. I just think its the fact of having an 8 inch wheel in the back that would make me happy inside..

 

The 8" wheel opens up a lot of options for racing and such. Most sportsman series racers use the 28" tire like mine. The 255 certainly made mine look like I had a saggy ass (known as Pak ass). Did not like it at all..... Also, the 255 was actually $17 per tire MORE than the 275. Just another reason if you need one.....

[Grabber70Mach 107]

I have some more pics when they started taking off the clothes. It was an interesting day to say the least. At one point there were 3 girls dancing naked on a lift. The rod shop that sponsored the show knew how to bring the guys in.

 

 

Do you need my E-mail? :shifty::biggrin:

[Boogerschnot 12]

I would go 275, I just want to make sure it fits under a coupe rear end.. It looks as though the sports roof is a little wider.. Is your front end on a 4.25 b/s? I will probably just go with the 255 on a 7 inch wheel.. I will test fit my front driver side wheel to the rear passenger side and see how it looks with 225s on front and back and then probably be able to decide on what to do after that..

 

Test fit the 225, measure the difference and clearances and take some pics.. Then I should be good to find the right size tire..

 

Ive never known a shop to mount a tire and then dismount it because I didnt like the stance.. I think I will ask my guys if they would do that for me if need be..

[coz 108]

Do you need my E-mail? :shifty::biggrin:

 

It's a yearly event in Millersville/Severna Park area. I think it's mid June. I'll post the date in the Events area. Besides the ladies, they have a dyno machine, give aways, grab bags, food and music. Plus it's a full service performance shop.

[Pakrat 1,043]

The 8" wheel opens up a lot of options for racing and such. Most sportsman series racers use the 28" tire like mine. The 255 certainly made mine look like I had a saggy ass (known as Pak ass). Did not like it at all..... Also, the 255 was actually $17 per tire MORE than the 275. Just another reason if you need one.....

 

[SELLERSRODSHOP 13]

grab bags??? let me guess, the one's too ugly to take off their clothes!!!:scared:

[MDinDestin 14]

What about on a coupe.. Im going to run 225 60 15's on front with 4.25 b/s and 255 60 15's on rear with an 8 inch rim and 4.5 b/s See any problems? Could I get that 275 under the rear?

 

My rear is dropped an inch with 4.5 leafs and KYB'S

 

The coupe, convertible, and fastback all have the same size wheelwells.

 

The 255s will not rub when using 4.5 inch backspacing on an 8. You have Coz's actual experience above to guide you on the 275 issue.

 

Since you're buying new, how do you feel about plus sizing up to a 17" or larger?

[MDinDestin 14]

Kinda wondering about the 4,5" BS on an 8" rim with 295? I run 18x10 with 6.4" BS with 295/35/18 and that's absolutely perfect, barely (not) touching the fender or frame/inner fender. Your setup will rub the fender lip, rolled or not... :blink:

 

There are two sides to a wheel to contend with; backspacing and what I call outboard or front spacing.

 

If cphsonic is running 6.4 BS on a 10, the other side of his wheel (the outboard size) is 3.6". So, he's running 3.6" of front spacing with a 295.

 

The OP is talking about running 3.5 outboard with a 295 so his car should be less likely to rub than cphsonic's. However, when taking into account the larger sidewall bulge of a 50 series tire, there may well be a problem.

 

IMO, for 15 x 8s, the 275 is a better choice here. A 295 may fit an 8" wheel, but it's not the optimal size and may rub and limit lowering options.

[MDinDestin 14]

I would second that. On my 17x9, 5.5bs wheels they seem just about perfectly centered, maaaybe could go in .5" on each side, and a 275/40/17 fits fine. 9" rim, 5.5bs = 8" rim, 5"bs. A 4.5 would be out farther...

 

As far as the wheel itself, the outboard portion of his rim is the same as 70 Verts. Both have 3.5" of front spacing.

 

Again, the OP will have the increased bulge of the 50 series tire to contend with. It is a factor and it is one of the reasons why plus sizing works. The shorter the profile or aspect ratio, the wider you can go.