Bigger/Wider Bolt on Wheels for rear (no mods or rubbing)?

[1987cp]

its the offset you need to be concerned about, just make sure its very close to stock most likely (+13mm) and you might be able to pull off 255's but it will be close.

13mm offset? Where?

255s, especially out back, will be just fine with the right wheels. I've even installed my Western 15x8.5s with 255/60 tires and ludicrously little backspacing (still haven't got around to measuring it ....), and experienced no rubbing problems.

Come to think of it, Blaze86Vic ran this exact same combination, probably with the same backspace, definitely the same tire size and model, on the rear of his '86 Vic for quite a number of years and was quite happy with it.

[Spaceboy]

I'm probably going to go ahead and order this, so...just want to confirm what ya'll are saying...

Will this wheel:

http://www.summitracing.com/parts/CRR-3975812/

Wheel Width (in) 8.00 in.
Backspacing (in) 4.000 in.
Offset (mm) -13.00mm

And a set of 255/60/15's fit on the BACK?

What I'm planning to do is buy a set of two tires/wheels for the back, and try them on the front before buying another two.

[P72Ford]

That will work.

You can actually go to a 275 60 15, which looks much better in my opinion. But when you load the back seat up, the tires may rub the inner fender lip.

No worries though. I added wagon straight rate springs and F150 shocks, and never had that problem.

My '90 with the 275s on the same dimension wheel:





The 255s look kind of small on there. My brother had them on his car for a while.

Kind of a shitty pic, but 255 60 15s on the rear. The wheels a Chrylser rally wheels, 7" wide.

[King_V]

Yeah, I've run into the same problem with the FAQ - click on the FAQ link - and neither "rims" nor "wheels" returns any matches.

Wait, 98-02? Does that mean 92-97 Panther wheels won't fit a pre-92 Panther correctly?

[82LTDQS]

Anyone running 15X10 inch rims in the rears? With 4 inch back space? Thats what Im planning on getting. I guess if all the above mentioned wheels (15X7 and 15X8) have 4 inch backspace and they work, then 10 inches will be fine. Any advice? I plan on using 295/50/15 tires.

[merc91]

stock +13mm offset being the distance from the center plane of the rim to the mounting face of the rim. -13 would be a difference of -26mm which would put the center of your rim 1" out further, and also the tire's center, which is the main focus. so 26mm plus 20mm (half of the difference in tire width) would equal 1.8" out further of the outside edge of the tire. and 26mm-20mm would put the inside edge of the tire 1/4" out further than now in the end.

i'm guessing with a 255 and -13 offset with stock suspension you might get some rubbing on the inside of the outer fender in the back when you compress the rear suspension. For the front I personally would hang around 225/70/15's with stock stuff.

I love my 275/60/15 BFG's and your gunna like he bigger tires allot... my next set will be a fair bit bigger tho until my wheel wells are full to the nuts, lol.

good luck with er, andy

[1987cp]

Anyone running 15X10 inch rims in the rears? With 4 inch back space? Thats what Im planning on getting. I guess if all the above mentioned wheels (15X7 and 15X8) have 4 inch backspace and they work, then 10 inches will be fine. Any advice? I plan on using 295/50/15 tires.

Not on a sedan, but I can measure the ones I've had on the wagon and tell you for sure how much backspace is too little. I'm guessing that in theory you'll need at least 5" or 5.5" backspace to fit 15x10s in the rear, but that's pure speculation at this point.


Oh, and to the OP: Yes, 255/60/15s fit okay on the front as well as the back, provided you're not shoving them out too far. Which reminds me, I still haven't measured the above-reference wheels, either.


EDIT: all four of my "Western" turbine wheels have 4" backspacing. That's two in 15x8.5 and two in 15x10. The set of four does fit on a wagon with 255/60 and 275/60 tires, but I've experienced wheel-lip rubbing front and rear with that combo. I have run the 8.5" wheels on the rear of my Crown Vic as an experiment, and they fit fine with their 4" BS.

This means that with the 15x8 US Wheel 75 Series with 3.75" backspace I'd had on the wagon previously, those wheels stuck out only a quarter-inch less than the referenced 8.5" turbines. This is interesting, since I don't recall those wheels instigating any rubbing in the front with the same 255/60/15 tire size (albeit Radial T/As instead of Yoko Avid S/Ts).


EDIT #2: Linky to pics of the Colony Park sporting the set of turbines described above:
Front ........ 15x8.5" wheel, 4" backspacing, 255/60/15 tire.
Rear ......... 15x10" wheel, 4" backspacing, 275/60/15 tire.

http://beta.supermotors.net/registry/16474

[1987cp]

stock +13mm offset being the distance from the center plane of the rim to the mounting face of the rim.

Hm. I just made a couple more measurements.

14x6.5" steel wheel from '79 LTD: 4.25" backspace, or about 13mm positive offset.

16x7" (or so I'm told; haven't measured the width personally) steel wheel from '98 Vic: 4.75" backspace, or about 19mm positive offset!

So that means a couple things. One, that you're correct about stock Box wheels having +13mm offset, and two, where in the dickens did I get the misinformation about stock wheels being zero offset?

Also, I'd never bothered to wonder before, but in offset terms, both my 15x8 and 15x8.5 wheels have -19mm offset. So evidently, that much negative offset on an 8" wheel is borderline acceptable and in an 8.5" wheel is too much (at least, for mounting in the front with a 255/60 tire). It would appear that you're definitely correct about -13mm on an 8" wheel (4" BS) being pretty comfortable while looking a lot more aggressive than stock.


Now my curious question is, at what amount of backspace (or positive offset, if you prefer) does a 15x8" wheel with a 255/60 tire begin to rub on the inside?

[Spaceboy]

Your setup looks bitchin' P72Ford -- but I'm not looking to do any upgrades to the suspension (yet) so I'll probably go with the setup mentioned (although some of the later posts confused me a bit, not sure if that means I'm going to have problems or not).

Crager does have some with other backspacing options. If 4 inches is going to put the wheels too far out with this tire, is there a safer choice?

Of course, in my book - wider is better!

[1987cp]

Cragar does have some with other backspacing options. If 4 inches is going to put the wheels too far out with this tire, is there a safer choice?

Maybe you need to look at the posts again.

4" BS was a slight problem with my 15x8.5 wheels on the front of the car with 255/60/15 tires. The same wheels and tires on the rear were not an issue, and if Blaze86Vic's turbine wheels really were identical to the two 8.5" rims I have, these same wheels are not a problem on the front of a car with a 245/60 tire.

I did not experience rubbing with the same size tire on the front with a 15x8 wheel with 3.75" BS, which stick out just a quarter-inch less.

A 15x8 wheel with 4" BS and 255/60 tire should clear just fine on either the front or rear. Look at the dimensions again - backspacing is the distance from the mounting surface to the back of the wheel, so this wheel will tuck in 1/2" farther than a 1/2"-wider wheel with the same BS.