back space on 15x12s..

[lowriden58]

hey guys, i tried to search and couldnt find much on this. im wanting to run 15x12s in the rear of my 71 but not sure on the bs? anyone know what i should run? i was thinkin 5.5 but i did run across 1 thread and the guy said he was running 7.5" . i just need some confirmation i guess

[gringoloco]

5.5 works for 10s, so 7.5 sounds right. You will have to mini-tub...

[special-K]

With 12s I`d think you`d need to worry about offset as well as back space.Are you trying to fit these on a no-cut frame/standard width axle?I ran 12s on a pro-street truck that was back 1/2ed and tubbed.I wanted that and ran the biggest tire I could.I`ve never looked at 12s fitting on a stock body/frame.My guess is they won`t fit.Maybe guys are doing it.We`ll see what answers you get.Just telling what I know.I like deep dish.

[70c10]

Originally Posted by special-K

With 12s I`d think you`d need to worry about offset as well as back space.Are you trying to fit these on a no-cut frame/standard width axle?I ran 12s on a pro-street truck that was back 1/2ed and tubbed.I wanted that and ran the biggest tire I could.I`ve never looked at 12s fitting on a stock body/frame.My guess is they won`t fit.Maybe guys are doing it.We`ll see what answers you get.Just telling what I know.I like deep dish.

I agree. If you don't wan't to mod, I believe we only have about 14" max from frame to edge of wheel opening. If you run a 12" rim that leaves only 1" of rubber on either side of rim to stay tucked and that's rubbing the frame. If you go with a 10" rim you have 4" to play with as far as backspace and offset.

[lowriden58]

yeah this is on a stock frame and axle. of course it will be mini tubbed just trying to get the largest tire/wheel combo in there so i can get some traction. ive see pics of guys running 12" wheels before matter fact someone posted a evilbay auction yesterday on here with a "riced" out chevy.

[PA-IndianRider]

There is another thread on this forum that is discussing wheel/tire with I think you would like to read:
http://67-72chevytrucks.com/vboard/s...d.php?t=288044

Hope this helps... as you can see for reading this info and the info found here there is a lot "different" views on what works and what doesn't.

So the more info we get the better.... thanks

[lowriden58]

Originally Posted by PA-IndianRider

There is another thread on this forum that is discussing wheel/tire with I think you would like to read:
http://67-72chevytrucks.com/vboard/s...d.php?t=288044

Hope this helps... as you can see for reading this info and the info found here there is a lot "different" views on what works and what doesn't.

So the more info we get the better.... thanks

thanks, BTW weld makes 15x12's and 15x14's for our bolt pattern.. i believe the largest BS they offer is 7.5

[PA-IndianRider]

Originally Posted by lowriden58

thanks, BTW weld makes 15x12's and 15x14's for our bolt pattern.. i believe the largest BS they offer is 7.5

With GM rally wheels (8") & 9" wide Mickey Thompson 60 series tires there is still 5" of clearance between the back side of rally wheel & the back corner of the trailing arm (which could be trimmed for more clearance).

This setup has the tire just past the fender (wheel well) by less than an inch. So unless you don't mind the tire sticking out of the wheel well the "front spacing" needs to stay the same as this rally wheel.

The "front spacing" & "back spacing" on the 8" GM rally wheel I have is almost "equal" (4 " each) so when comparing wheel/tire combos "do the math".... for in most cases once you "mount them they are YOURS" !!!!!