I know all about proper backspacings to avoid rubbing on trucks, but i never have really learned about it on the 4th gen. So i thought i was ask what backspacings are needed on the 4th gen to avoid rubbing. I've been mostly looking at 8.5" wheel widths and not sure what backspacing or 'offset' is needed (mostly since i've been looking at BMW applications of wheels)

Also what are typical tire sizes used for 18" and 19" wheels?

thanks!

steve

 

Backspacing depends to a large extent on the width of the wheel:

Stock 16x8 55mm offset, 6.65" backspace

Stock (WS6/SS) 17x9 55mm offset, 7.15" backspace

Not many people run the 8.5" wheels. A 50mm offset would give you about a 6.75" backspace, and the outside of the wheel would sit about 1/2" further toward the outside.

Typical 9.5" wide wheels:

TT II's 17x9.5 45mm offset, 7.0" backspace
OZ Monte Carlo 17x9.5 49mm offset, 7.2" backspace
ZR1 replica 17x9.5 56mm offset, 7.4" backspace

Typical 11" wide wheels:

ZR1/GS replicas 17x11 50mm offset, 7.93" backspace
TT II's 17x11 45mm offset, 7.75" backspace.

When selecting tires for 18" or 19" wheels, you want to keep the outside diameter of the tire as close to stock (25.65") as possible:

245/40-18 = 25.72"
275/35-18 = 25.58"
285/35-18 = 25.85"

275/30-19 = 25.50"
285/30-19 = 25.73"

 

So Injuneer, a 8" wheel with a 38mm offset would stick out 1.8cm further than an 8" factory wheel right?

Am I understanding this correctly???

 

17mm, or 0.67"