78-80 Gbody with 18's

[eversmann79]

only places online that let you return tires if they dont fit?

 

[jrm81bu]

I'd be more concerned with the backspacing than the overall width first. Regardless of the width if the backspacing is wrong then it isn't gonna work. Too much backspacing can be fixed with spacers or adapters, but not enough backspace cannot be helped.
And usually once you mount a tire, it's yours.

 

[eversmann79]

whats the least amount of backspacing alotted? 3.75 and up on an 18.5 inch wheel?

 

[jrm81bu]

I've got 4.5 on a 8 inch wide rim. I'm sure I could go 4, but i'm not sure how much more you could go. With a rim width of 8.5 4 inch backspace might be the minimum. The more the better, but the limit will prolly be real close to the 4.5 backspace. You're gonna want to tuck as much as possible.

 

[eversmann79]

so if they are 4" or more bs buy them?
the only thing i could find on the is they have a +18mm off set

 

[jrm81bu]

I think if it is 8.5 wide, that will put the backspace around 4.5. Should be ok.

 

[eversmann79]

ok anything less than 4.5 is a no go then?

 

[jrm81bu]

ok anything less than 4.5 is a no go then?

You will have to decide that. 4 might work but it will be close to hitting, depending on tire size, when turning.