Reply to "narrow body wheels"

modok,

Why don't you use your current wheels to help you determine the backspacing you want? If you know your wheels stick out say a 1/2" too much, add that into your backspacing to move them in 1/2".

Conversely, if your wheels in the back are in 1" too far, subtract that from your wheels backspacing to move the wheel out 1".

You start to measure backspacing by placing the wheel face down. Then you run a straight edge on the outermost part of the rim at the beadseat spanning the center of the back of the wheel. You then take a tapemeasure and measure the distance from the back face/pad where the wheel mounts to the car (where the lug nuts go through) to the bottom of the straight edge. On my wheels (for a 5-S, 13" wide at the rear), this distance is 5".

Backspacing and offset are not the same thing. Offset is how far the mounting face/pad is from the center of the wheel and can be positive or negative. For instance, my same rear 13" wheel with a backspacing of 5" has a negative offset of roughly an 1 1/2" (-38.1mm) because that's how far the mounting face/pad is in from the center of the wheel. So if the mounting face/pad is further under the car than the center of the wheel, you have a negative offset. If it's closer to the outside of the car than the center, you have a positive offset. If the mounting face/pad is directly in line with the center of the wheel, you have a zero offset.

Whenever I order wheels I order them by backspacing and let them figure out what the offset is. You don't need both to order wheels, just one or the other.

If you're not sure how much farther you want to move a wheel out, make some spacers with wood in 1/2" and/or 1" increments. They don't have to be round as long as they clear the caliper, and none of the holes have to be precision. Take the wheel off, start with the spacer amount you think you want, and take it from there. You can even turn the front wheel back and forth to check clearances. I did this just by using blocks of wood that I placed between the wheel and the rotor and tightening the wheel down. It will give you the 'visual' of what the wheel will look like on the car. Just remember to subtract that amount from your current backspacing, and that's what you would order. DO NOT DRIVE THE CAR WITH WOODEN SPACERS! That could be disasterous!

If I were to move a wheel in, I'd probably want it to be flush with the wheel opening. I'd take a straight edge, put it across the wheel while on the car, and measure from the inside of the straight edge into the body along the wheel opening where I would want it to sit flush. Once you get that measurement, you can then add any amount you want to if you wanted to move the wheel further under the fender. You would then add this amount to your current backspacing to get the desired wheel placement.

All this can be easliy done with just a bit of effort on your part.

Michael