Vlocity

I have a wheel problem and need to know the correct Offset and back spacing for a 9.5 inch wheel.

I take from searching several posts that the backspacing should be 8 inches.
What should the offset be for that width wheel.

Thanks,

Ken

Cosmo Kramer

How wide of a tire are you going to run?

IcemanG17

Ken
9.5 wide with 8" back should work fine.....my fronts are 10" with 9" backspacing....with minimal fender rolling I run 295/30-18 front tires and I can even do U turns no problem...but I do have double steering rack stops

Vlocity

Hey guys,

I'm running a 275 on the front 9.5. The problem is that I had a new set of wheels made and when I went to fit them they stick out about an inch. Luckily I didn't provide any of the specs.

I just want to make sure that on the redo, they get it right.

So for a 9.5 inch wheel with an 8 inch back space, what would be the offset.

Ken

JWise

FWIW, the factory Cup Racer wheel (basically a wider Cup 1) is 9.5x17 ET68.

hacker-pschorr

The higher the better, you can always space them out

Wouldn't it be nice if every Porsche wheel was produced with an et70 offset? Just use the necessary spacer, every wheel would fit every 5-lug Porsche (well, almost).

Rick Carter

If you had long enough bolts when you add spacers, or use bolt on spacers with their own lugs.

DR

What JWise said ^^^^

Anything higher and you can get into physical interferance on the back side with various "stuff" without adding additional steering rack stops.

IcemanG17

http://www.autolounge.net/calculators/tirespacing.html

Ken
An 9.5" rim with 8" backspacing has an offset of 69.8mm vs my 10" rims with 9" back have an offset of 88.9mm

Another calculator I like to use to determine rim position vs stock is this

http://www.1010tires.com/WheelOffsetCalculator.asp

Using a stock 7" rim with 65mm offset then entering my 10" rim with 88.9mm offset you end up with an inner position 61mm LESS than stock (closer to inside) and only 15mm MORE towards the outside (towards fender)...just as a comparison my Carrera III's are much better on the inside with only 5mm closer BUT the outside is further out at +21mm...... The CIII's with 235/40 tires do not rub at all....not even close with a totally stock setup and about 155mm ride height

On the widow with 295/30 fronts and double rack spacers at about 110mm ride height it only rubs a tiny bit at lock over U turns...& even that isn't bad & the turning circle seems about the same as sharky?

Ispeed

My fronts are 9.5x18 et 68 with a 265/35/18 tire on a stock S4 with no rolled fenders. I talked to Kim Crumb before having them made, and no rubbing at all.