??????? on backspacing

can i run a 20 by 8.5 with +35 mm of backspacing on a 87 s-10 with 235/35/20 tires???????????????????

i ment 225/35/20 .

I show only up to an 8" on the front with a -6 to a +6 offset to keep from rubbing inside and out. Rear can go up to a 9.5 with a -6 offset our guide can be a little conservative but an 8.5 with a 35 is way beyond what we determine will fit.

225.35.20 is a little narrow for an 8.5 they'd be stretched. 235.35.20 on the right wheels will work on all 4 corners.

I am assuming your truck is 2WD.