froggy47

Ordering custom Forgestar rims. I have talked to several sellers and each suggests different offsets, not much different but still.

Forgestar themselves suggest 34mm f, 52mm rear.

Vendor a) 36mm f/56mm rear

Vendor b) 35mm front 52mm rear

Vendor c) 38mm front 53mm rear

So I know it depends on ride hgt, camber, tire size etc etc yada yada

I can add small spacers IF NEED BE for small increase corrections for camber/tire choice. But can't go the other way.

What should I order? What have you got on your 18's? Do ALL of these work? I don't want to over think this, but these are NOT returnable if they don't fit my car. I know 1 mm is not much. I will measure my ccw that I use with spacer (included) and post later. That should help. Got to go out now.

clubracer23

l98tpi

18 x 11 Deep Concave 40mm offset

18 x 12 Super Deep Concave 45mm offset


Still shot to see fitment

action shot to see how fit under fenders during chassis roll

froggy47

Thank you guys

froggy47

So I looked at the stock rims (offset printed on rim) and calc'd the ccw's I have (diff width than what I am ordering).
Stock 18x9.5x40mm front
19x12x59mm rear
Let me ask a dumb question (maybe not so dumb). If the oem offsets are calc'd to clear everything, and if the new rims were to add whatever more width to both sides EQUALLY, sure everything gets closer tolerance wise, but, why would you not just use the stock offsets?
Please discuss.

PS If I measured correctly, the ccw's I have (with the spacers I have to use to clear caliper & LCA included in the measurement):

18x10.0x44mm front
18x12.0x67mm rear
It's possible I mucked up the measure as tires are mounted, so I had to work around that to the rim measures.

Those fit good with the spacers.
Would ccw require different offsets than forgestrs because of spoke design. Is that why these that I use with spacers are quite different from the forgestar suggestions, especially rear? Forgestar is f14 (that and cf5 are the only ones that work).

My ccw are c14, I know I mucked up because when I measured the overall width (to ground) and measued hub to ground that included some tire bulge. 3-4 mm rear and probably 6-8 mm front. So disregard those offsets and just discuss why not use the oem offsets. Sorry.

froggy47

Your fronts are the same offset as my 18x9.5 stock, but the rears are 14mm different, that seems funny? Never mind, sorry, I did not realize there are 3 f14 styles, things just got even more complicated, grrrr.

clubracer23

Offsets change dramatically based on width.
https://www.autoanything.com/wheels-...el-backspacing
Where are you located? Maybe you can borrow my wheels or someone else's to try on for size.

froggy47

Thanks, I think maybe the different spoke shape/attachment may make comparisons re: ccw and forgestar difficult or not conclusive.

I don't want to screw up an almost 2k expense. Why I'm beating this to death.

froggy47

So called Forgestar again & settled the difference in the 3 f14 styles reg/deep/super deep. Neg on reg and he said super deep is mostly for wide body add ons to the c6z body. Or for the look. Not sure why that info was not important on my first call and/or why none of the vendors went over this? Grrr.

He explained the actual spec on the build is +/- 1 mm or 2. So ok.

So for 18x11 and 18x13 (deep) he suggested 37/51 which is in line with most of the vendors now that I got the +/- info.

I will run more than stock neg. camber so does that mean higher or lower offset numbers? Say -2.5/-1.5 neg give/take a touch.

Looking at l98tpi I feel 38/39/40 all are ok. Rear he has super deep so I can't use that.

froggy47

As usual to answer my own ques. bigger number moves rim in, smaller moves rim out.

Looking like 36mm f, 56mm rear.



Ordered some in silver. 8-10 wks