In either a 15x3.5 or a 15x4 inch wheel, what backspacing did you end up using? I would like to *assume* that the 3.5 rim only comes with a 1.75 BS as this would seem logical to me but I have been wrong before(and will be wrong again before I die!) What BS did you use for the 15x4? Any info would be great. Thanks!

 

You are correct on the 15x3.5, I don't think I've ever seen any options for their backspace. - Sorry, I never run a 15x4 so I cant give you anything exact there, but logic woud say that something of an even bs would keep it fiarly cleanly centered in the wheel well.

 

Ideally, you'd hold the offset constant (and close to whatever the OE offset was).

Assuming that your 3.5" wheel is an alloy wheel, 1.75" b/s translates to about -1/2" (or -13 mm) offset.

-1/2" offset in a 4" wide alloy wheel would be 2" b/s.

If the 4" wheel comes with 1.75" b/s, I wouldn't sweat the quarter inch change in offset or the half inch wider front track that would result.


Norm