Bill Verburg

ET = backspace - .5*overall width

BillJ

Well it turns out I am not going to use these solely based on not buying the car I thought I was and picked up something totally different. Need to cover my time and expense on these so $1100 plus shipping

guardsredcab

Did you ever figure out the offsets?

BillJ

No. Cleaned them up a little and put them on the tire rack in the garage. Newborn taking all my time right now

BillJ

Ok so overall width on small rim is 9". Backspace measurement is 7 1/8". This equals an 84 ET? Wide rim is 11" and a 7.75 backspace so ET of 72?

Bill Verburg

Ok now we are getting somewhere

Once again the original sellers lack of understanding about wheels has led to misrepresentations

for Fikse wheels if the overall width is 9" the bead width is 8", overall width of 11" is a bead width of 10"

using the #'s provided
fronts are 8 ET66.7
rears are 10 ET57.2

I suspect something in the measurements is off as fronts for a 993 should be ~8ET52+/- and rears should be ~10ET 65+/-

BillJ

The calculations you provided said to use overall width not bead width. Can you clarify?

Bill Verburg

ET = backspace - overallwidth/2

in your case and converting everything to mm
ET = 7.125 - 9/2 = 180.975 - 228.6/2 = 66.675
and

ET = 7.75 - 11/2 = 196.85 - 279.4/2 = 57.15

just for comparison oem Speedline 8 & 10

ET = 166.3 - 228.6/2 = 52

and

ET = 204.7 - 279.4/2 = 65

guardsredcab

Bill, Sending PM

BillJ

Ok

guardsredcab

sorry, i meant Bill Verburg. now i'm sending one to you.

BillJ

Took detailed measurements and here are the numbers.

17x9 - overall width 315mm. Backspace is 232mm. I calculate that as a 74.5 offset

17x11 -overall width 346mm. Backspace is 247mm. I calculate that as 74.

Bill Verburg

I'm not picking on you or anything just trying to get things straight

overall widths of 315mm and 346mm are just not credible

BillJ

That is fine Bill. I understand your intent so ignore your tone.

Now that I know how to convert inches to mm here is what i found:

17x9 - overall width 248mm Backspace is 184mm I calculate that as a 60 offset

17x11 -overall width 274.6mm Backspace is 196mm I calculate that as 59 offset

Bill Verburg

Given the fact that Fikse have .5" flanges it appears that the fronts are 9" ET60, and that is in the ballpark for what it needs to be to fit the front of a n/b 993, the backs appear to be 10 ET59 which is also about right if a bit on the aggressive side.
assuming all the provided #s are correct the 9" fronts sit 4.7mm closer to the lip and 20.7mm closer to the suspension than 8 ET52 oems, the 10" rears sit 6mm closer the lip and 6mm further from the inner wheel well wall trhan oen 10 ET65