3rd gen with a 4th gen rear end, 15x8 wheel...what backspacing would I need to allow a 10.5 tire to not come in contact with the quarter.
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Also what backspacing with a 10 inch rim?

 

Anyone have any idea?

 

A 15 x 10'' rim normally needs 5.75 or 6'' backspacing so with a 4th gen rear you will need 7.75" backspacing

Here's a good link to read:https://www.thirdgen.org/forums/susp...t=10+inch+rims

 

I'm thinking 8" rim with 5.5 bs....hopefully.

 

A fourth gen rear has an extra 2 inches sticking out!
If you put a 10 inch rim with 5.5" backspacing it will stick outside your fender by 2 inches!
If you have a 3rd gen rear you could run the 5.5bs but it could still hit the fender. I think 5.5bs on the stock rear lines up flush with the outside edge of the fender

 

I said im thinking 8in rim 5.5 bs, not 10in.

 

The 4th gen rear is almost 2" wider, but not a full 2". - I'm running an 8" bs with a 11" wide wheel on my 4th gen rear.

 

Well looks like my car is going to be a mul let mobile with wheels sticking out.

 

I run a 15x8 wheel with 5.5 backspacing with a 275/50/15 tire. Plenty of room to the outer lip, its actually tight on the inside with barely a finger width of clearance. I don'y know if this helps since you have the 4th gen rear, but it might give you somewhat of an idea.... thats my .02. Good Luck.

 

I am running a fourthgen 9" and am running 15x8 with 5.5 b.s. and it its perfectly flush with the quarter panels. I am running some pretty big 28x11.50's also. The only two options with the fourthgen rear is 15x8 with 5.5 b.s. or 15x10 with 7.5 b.s. both of these combos would product the exact same look from the exterior as the extra 2 inches would just go into the wheel well. I will try to get some pics of the new setup.