jleonard71

Well if you just go by wheel size, then the formula is 6.35mm of offset for every 1/2" of wheel width, because for every 1/2" of difference in wheel width it sticks out 1/4" (6.35mm) more or less on each side of the wheel. So going off Ken's numbers it would be:

19x11 +61
19x10.5 54.65
19x10 +48.3
19x9.5 +41.95
19x9 +35.6

But you can't just use wheel width because the wheel isn't what's going to rub, it's the tire. My calculations take into account where the outer edge of the tire will be, given each offset and wheel width, and the numbers I posted will put the outer edge of the tire at the exact same spot as where Ken's are. That is of course if you are lowered like he is, as I mentioned it will be a few mm different if you're at stock height. And the tire sizes listed are the sizes that will make the sidewall of the tire exactly flush/parallel with the face of the wheel, just like Ken's, and not stretched or bulged at all.

Fsport2UR

The problem I see with 'adding' in the tire size to the offset, is all tires aren't the same. As mentioned by Figs, one of the 305 tires they measured was a full inch wider then the others. That difference will drastically impact any offset. I do agree the tire is what hits the fender or suspension so it should be apart of ones decision making. To me first and foremost would be what specific brand and size tire you want to run, and then decide which offset to run. And after all that, the real ****ty part, most wheel companys don't even offer good offsets for the ISF. HAHA

jleonard71

True, but they also said the PSS was the widest out of all the tires they measured, and that's the tire that all of those numbersare based on. So that's why I said that those measurements will guarantee that everything will fit with no modification, and if you use a tire that has a narrower tread than the PSS or aren't lowered you can go with several mm less offset and still be fine.

And a lot of brands these days are offering custom offsets without having to order a completely custom wheel and pay an arm & leg and wait months for delivery, i.e. Avant Garde, Ace, TSW, Niche, and I'm sure many others.

Fsport2UR

IC. But in your original post you never did state you were using PSS tires as a reference since they are the widest...which is why I mentioned it. But considering also, others may want to run a 275 on a 9.5" wheel. Or as you mentioned, some folks are ballzy enough to go 295 on a 9.5" wide wheel. In reality, most people don't know how to do the math.
Either way, I think the absolute measurement one must know is from hub to fender...and/or hub to suspension(backspacing). And then figure out which configuration of offset to tire fits. This is, if one wants to not roll/pull their fenders or adjust their suspension.

ISFpat

iTrader: (10)

getting back to posting pictures.. heres my fitment vs everyone behind me lol

Levin

This is one epic thread.

subiepunk

iTrader: (7)

Can I play?

Meraki Autoworks

iTrader: (8)

^ wtf that was quick! LOL post some more pictures, side, rear, and the fitment!

IsfClyde

jiggahwh0

subiepunk

iTrader: (7)

Need to get more pics, here's one dphoto took from the Westminster meet.

Meraki Autoworks

iTrader: (8)

needs moar low.

JNguyen228

iTrader: (1)

These look small. 19s?

VicTornin

Rotiforms.. 19x10/11

DAng87

iTrader: (1)

this looks great!!! specs please!!