Okay dumb ??? of today

On my racer I run 18x10x65mm wheels. In the rear I have a 1" (25.4mm) hubcentric spacer....SO does that mean I am effectively running an 18x10x39.6mm rim?

I am trying to find out what offset 11" wide rims I need....my car came with 11" wide 17" Forgelines, but I don't know the exact offset on those either...only that they are the "Devek" wheels with 10" fronts....those forgelines fit the car with 315/35-17 Hoosiers just fine with no spacer....

 

Yes...

So with no spacer you would be looking for an ET somewhere around 50-55 with an 11 inch rim, presuming that you have the wheel arches rolled and have some mm's to play with there...?

 

The fenders are heavily rolled.....whats funny is the 17x11x50.8mm (8 " backspacing) wheels with 315/35-17 fit with minimal rolling?? VERY tight on the inside, so much so that at full droop the tires rubbed on the inside of the lower suspension arm....but the 18x10x65mm with 275/645-18 tires would not fit at all, rubbed big time on the inside, hence the spacer to make it work, but that required quite a bit of rolling on the outside

I agree that the ideal 11" rim will be right about 50mm....anything more probably will rub on the inside....