Help! looking at some wheels on ebay, for my 1995 Formula.
17x9 with +35mm offset, the listing on ebay says they will work.
+35mm offset seems wrong??
How do I convert offset to backspacing?
I would like to run 275/40/17 tires.

 

A 35mm offset on a 9.5" wide wheel is going to be pushing it quite a bit toward the outside edge of the fender. I posted links to pictures of a 17x9.5" wheel with 49mm offset in this thread. There is also a link to a pic of a car with 45mm offset. For the 35's, you will move the wheels/tires about 1/2" further out than the ones on my green Formula, and about 0.40" further than the ones on the front of the black TA.

http://web.camaross.com/forums/showthread.php?t=390856

Whether you like the wheels out that far is up to you. Its an agressive look, but not everyone likes it.

I think the green Formula in the background behind my car in this picture has some wheels with the 35mm or 38mm offset.

http://cjcfo.fbody.com/members/injun...osD/SLP27a.jpg

 

Forgot to add the info on how to calculate backspace from offset.

Back space = (width of wheel/2) + (offset/25.4) + thickness of the flange that holds the tire on the rim.

For your 9.5" wide wheels, with a 38mm offset:

BS = (9.5/2) + (38/25.4) + 0.48 = 4.75 + 1.50 + 0.48 = 6.73"

The last term above (0.48) is a rough approximation of the typical bead retention flange. That dimension is going to vary from wheel to wheel. Sometimes it just easier to plug in 1/2" (0.50), but some wheels may have a slightly narrower flange.

 

Thank you Fred for the reply!
I checked out your website what an awesome car you have!

From what I gathered from your post you thought these wheels I want to buy are 9.5" inches wide, but they are only 9.0" inches wide.
You said that these wheels would stick out 1/2" wider than on your Formula, maybe since the wheels are only 9.0" wide instead of 9.5" wide they may work???

Doing the math I came up with 6.3779 inches of backspace. Hopefully enough??