Wheel rear spacing questions

[TR Custom Parts]

Bear with me on this one guys. I am running Hoosier Q/T Pros which measure 27x10.50x15 on my GN. I put them on Weld Draglite wheels that are 15x7 with 3.5" rear spacing. I think the wheels suck in the bead too much and it looks like the tire contact patch is not correct. Center of the tire is wearing more then the outer edges. If I go to a 15x8 Weld Draglite with the same rear spacing I should get a better contact patch but how will this affect fit in the wheelwell? In other words will the "tread" area still be in about the same position since I am using the same rear spacing? I would think by having a wheel 1 inch wider with the same rear spacing would just move the bead area out but not the tread? Anyone following me?

 

[John Larkin]

Well, if you use an equivalent backspace, then the inside bead of the rim will stay in the same place in reference to the chassis. The outer bead will move out as rim width increases. Wh will this do to tire patch? It will straighten out the sidewall somewhat so tire patch should effectively increase because it will flatten the "hump" across the tire face now that the beads aren't quite so sucked in.

 

[Red Regal T]

I THINK THERE IS NO PROBLEM WITH GOING TO 15 X 8s WITH THE SAME BACKSPACE AS JOHN SAID. WE'RE TALKING SLICKS, RIGHT? CONTACT PATCH AT WHAT TIRE PSI? GET DOWN TO 12#s WHERE THEY WILL REALLY GRAB, YOU SHOULD GET A GOOD CONTACT PATCH WITHOUT CHANGING RIMS.

 

[TR Custom Parts]

These are Q/T Pros which are essentially slicks with 2 grooves cut in them to make them "street legal". (Haven't tested that on a cop though!) I run them on the street on occasion and have them at around 18lbs. Obviously when racing I drop them down about 5lbs. I was just concerned about the tire being pushed out too much and hitting the quarter panel lip. (my car sits pretty low)