10" wide wheel on a Box?

anyone running 15x10's? currently running GM Sport truck wheels that were on the car when i bought it. They look decent, but not my style. thinking of putting some 15x10's on the car, keeping my current 275/60-15 tires so save a bit on cash since this spring it is getting a ton put into the undercarriage (suspension, Trans rebuild, Sway bars, etc...).

so, if you have 15x10's, or any 10" wide wheel. specs on BS/offset to know what should clear.

Pic of Car as it sits currently for reference.

The easiest way to get correct backspacing is to measure your current wheels, and get something with the same backspace. That should keep them from rubbing the frame

Fred Kiehl wrote:

The easiest way to get correct backspacing is to measure your current wheels, and get something with the same backspace. That should keep them from rubbing the frame

Not quite how it works. That will certainly ensure it will not rub on the frame, but that puts all the extra width of the wheel towards the outside of the car and could cause issues with my bodywork.

In theory, the same offset wheel will keep my tires centered where they are now, just eliminate the sidewall bulge caused by having a wider tire on a 7" wheel vs the more square profile i will get with a 10" wheel but not actually move my tire placement any so not causing any rubbing anywhere.

Was hoping to see someone with first hand experience running 10" wide wheels to verify more or less.

Current wheels are 4.5" BS, but on a 10" wheel i am looking at 5.5" BS. though more Backspacing, offset is different and will actually move the tire closer to the outside of the car. by about 1" as my current wheels would be a +13 offset, and the wheels i am looking at are a -13 offset. I get the theory and the math. I just like to see it before i pull the trigger.

It does work that way. The issue is that the width rim you are using are extremely wide, and may cause you issues on the inside. Actually the 10 inch rims will fit under the car, but when you start putting wide tires on them, the tires interfere on both the inside, and with the body on the outside. Sometimes you can not have your cake and eat it. Wider wheels make the sidewall bulge more, and that is what usually hits the surrounding parts. On the front you must make room for the tires to turn, so pushing them out until they do not touch is the only option.

backspacing will change with wheel width,  offset however does not.  


keeping the same offset at my current wheels, but a wider will will not change tire placement.  keeping the same BS will however change tire placement.  a wider wheel, but the same offset even though more backspacing will not actually put my tires any closer to the frame than they are now but square up the profile.  


Check out this diagram.  it compares my current wheel to a 10" wheel, keeping the same offset.  the tire does not move,  but the wheel certainly does.  Offset stays the same,  BS does not.   hence,  if i kept the same backspacing i would have more room at the frame side, but much less on the fender.  I am going somewhere in between i think.  a bit more offset to push the wheels out some,  but definitely not keeping the same backspacing as i know that has no chance of working.

You may do whatever you want to, and if it does not work you will have to deal with it. You want something the car may not be able to accommodate. You do not allow for sidewall bulge. It boils down to a trial by error situation. You must also make sure the body is centered on the frame, or one side may be different from the other. Remember to calculate the compliance of the differential housing bushings in your final fit, or you will be rubbing in a turn.

These cars rub the frame in the front when steering with 225s on them, so they will surely rub with anything wider.

as mentioned, i am already running that tire size. No rubbing with my current setup. rear is no issue, people are running 305's on the rear without issue, despite some lateral movement in the rear axle from bushing flex and the limitations of the short arm 4 link system. a 5th link or watts link would eliminate any possible movement should it be an issue, but it has been proven to not cause anything problems.

as for the sidewall bulge, you are correct, but it will be less bulge than i have now. Never seen these cars rub with a 225, considering my 2" wider 275's, i find that hard to believe unless it is a very high aspect ratio.


it is trial an error, which is the primary reason behind asking for experience of those who have done it already. I can postulate all day on what might and should work, but real world experience is king in these cases. I know a x10 will fit, but exact offsest will be key. If no one else has the info i need, then i will happily do the estimation an buy what i think is best and make it work. have plasma cutter and a welder....anything is possible.

If you are getting a wider rim, the sidewall bulge will be larger (wider) on the rim with the same tire.

I disagree, as it will more inline with the profile of the tire itself.

Put them on the wheel and measure it.

If I go this route, I will do a comparison of the current vs new as I change them out.

I used a 15x10 on the rear. Fit was very good. I had rolled the fender lip from a previous set up. I think it would have worked with the revised back spacing.

According to the specs for the 275-60-15, the measured rim width is 8" with and allowable of 7.5-9.5.

Measured rim width is where the tire will be at the stated spec dimensions and other widths will distort it.

The "bulge" you talk about is all about definition. If it means how much it sticks out compared to the rim and tread it is one thing. If it means the amount of actual crossection at the widest point of the sidewall it is totally different.

IMO, a 10" rim is just as far out of spec as a 7" is and will cause the tire to be pushed down on the outside edges and overflex the sidewall out. Actual sidewall crossection will likely increase some amount. You will also have to run odd tire pressures, probably pretty high, to push down the center of the tread if you want good even road contact.

I would put them on and 8 or 8.5 wide rim of the same offset as long as you have similar amounts of clearance on the inside and outside.