20x12 rear setups need backspacing

[Chappo]

As title says I am trying to find out what backspacing would be required on a 20x12 wheel setup in the rear for a SWB, I am running porterbuilt rear trailing arm airbags, and running 17x9 with a 275/50/17 at the moment but wanna fill in wheel well.

Wheels are going to be American Racing VN470 Salt Flats.

please post pics if possible, main thing is that I want to maintain bed.

[jaime]

I got some raceline wheels I did a 22 24 set up I havent got tires yet  so I dont have pics butmine r 22x 8.5 bs 5.25 and 24x10 bs 5.5 and the 24 tuck in nice

[jaime]

Heres a pic of back wheel with out tire hope this helps

[Chappo]

what width do you plan on going with I was going to run a 315/35/20, which I know will work with the a wheel like streeters which are 20x10, and have about a 1/4 inch of gap from fender on the rear.

[jaime]

255 30 22     295 30 24

[Captkaos]

In reality with the right backspacing you can fit a 14" wide will in there. I would measure but I think it has to be 6" of backspacing with a 12" wide rim.

[jaime]

Can u fit a 12 inch wide wheel with out cutting  or shorting the dif

[Captkaos]

Yes it should fit with the right backspacing.

[78 Chevyrado]

its kind of a measure as you go thing...  please note...  the width of the tire, say 285mm  is NOT the width of the tread, but the width at the fattest part of the sidewall. 

When I fitted mine, I used a stock tire and wheel, found out the specs of the stock setup, then calculated what would fit in the same space (truck on ground with full weight on it)  Once you get those numbers, with no particular wheel or tire in mind, then you can go shopping. 

If need be though, you can always bend the 1" wide part of the wheel well up to gain more clearance... 

I picked out the wheels I wanted and bought them...  then went to discount tire, and they let me TRIAL FIT a tire on there to see how it would work.  Tried three different tires before I found the one I want.  What you need here is a good tire shop that will help you out...  they save me lots of time and money.