I searched and it seems the only problem people are having, it the tire rubbing on the fender. But I have the opposite problem.

I bought some used rims (5zigen Hyper 5zr) to use for autox. Then without thinking, I bought 4 BFG R1 245/45/18 and had them mounted. Then threw them in the trunk/backseat and went to the race.

This is when I realized that the tire was too wide and the rim didnt have enough offset. The tire is hitting the upper control arm (I think thats what it is) So now I need to find what size spacer I need to make these fit. Does anyone have any idea?

 

What is the width and offset of the wheels?

 

I believe they are 9". How do I figure out the offset?

 

Look on the back of the wheel...they might have a sticker or might be stamped with the offset

 

Either this ^ or you can measure the back spacing.
Take a straight edge to the back of the wheel and measure from the mounting pad to the straight edge. If you have an 8" wide wheel and you measure 5" from the straight edge to the mounting surface your offset is 1" (+25mm).

8" divided by 2 = 4". So if you measure 4" from the straight edge you have a -0- offset.
Works the same on any width of wheel. Divide the width in half (10" wide, would be 5.5") and that gives you the center of the wheel. If you measure more than half the width then your wheels have a positive offset, if you measure less than half then you have a negative offset.

Or you can check online to see if the manufacture lists the offsets and widths.

 

I didnt see anything on the back of the wheels and by the time I got ^ this message I was already in for the night. Here are some pictures... Oh and I didnt realize the size was on the back and I guess I measured wrong. They are only 7.5" wide.... How disappointing...

 

After looking online the offsets for the 7.5" 18's came in 35, 43 and 48. Is that what the 43 means?

 

Yep, ET 43 is the offset.

 

You can put a 15-20mm spacer with no problem.

 

I'd go with a 20mm, maybe even a 25mm just depending on how aggressive you want it. It'll look nice with a 25mm though.

 

Awesome. Thanks everyone. Ill post pictures after I get them.