will 235.35 work better on nf or df springs with a 40 offset?

 

Probably with NF's. I've seen 19x8.5 38 offset with 225/35's on DF's and it looks really really close. I think you'd be tucking the 20's on DF's with some serious potential to rub.

 

It also really depends on the width of the rim.

 

im on NFs and could not get the 235 35's in. the front would rub on a 40 offset which I have also. The rear will be no problem but I had to go with 225 20's... You would be rubbing pretty bad on DF's i think

 

What is the Wheels width?

 

8.5

 

You really want a higher offset if you can find one.

I show you will want a 235.30.20 on a 20x8.5 with a 45-47mm offset would be idea for a stock suspension set up. If you drop down from there and you want to avoid rubbing you are going to want to keep it tight to tuck and narrow the tire to prevent rubbing. (unless you don't mind rolling or moding)

225.35.20 is only a little taller than the 235.30.20 and it will fit between your fenders a little better. (the 225.30.20 will be stretched on an 8.5' wheel)