68 Camaro backspacing
 

On a 68 Camaro that is minnitubbed what's the widest wheel I can run and what backspacing do I need?

I have the Same car with DSE tubs 54.75" axle width and 18x12's fit with 5.5 back space

Safe is 11 inches and stated by DSE

You can do 12 but this requires you to be exact with fitment.

things to take into account:

Axle size
Wheel size - actual vs stated
Tire size and overhang - each tire shoulder is different
Actual mini tub clearance
The articulation of the tire during range of motion - Are you tracking this beast and doing heavy cornering?

68 mini tub
 

I have a 68 with 11" rims and 315s. Buy the rims FIRST then measure for the rearend. I do have enough room for 12" rim with 335s. I cut the frame rails a little more and stretched the tubs. I dropped plumb bobs at the inside of the center of the wheel opening with uncut lips and my car measured 69 1/2" ID quarter to quarter. If you look at the picture below you can see the strings hanging. Rearend is narrowed 56" OD rotor hat to rotor hat. Wheels are 18x11x5.5 BS. I could have the rearend at 57" and this would have made room for the 12" rims. If you have any questions let me know. REMEMBER every car is different so you have to measure YOUR CAR.

Guy

A few ideas
 

My 67 is still under construction but uses the following.

Owner narrowed axle 55 inches flange-to-flange
19x12 wheels with 6 -inch backspace.
Tires are Pilot Super Sport 325/30ZR19

Some things to think about

- If you can mock-up actual wheels and tires it is helpful but not mandatory. It just takes a little more planning without a mock-up.
- Don't forget the thickness of your brake hat/drum when planning. Mine are Baer around .3 inches thick and others vary.
- If you cut a little deep to make more room don't forget that as you push the tub in deeper (make it wider) it will pull the ends inward a little so plan to cut carefully to avoid a gap at the rear (don't ask me how I know this!)
- Fit changes depending whether the wheel lips are rolled or not
- Different tires have slightly wider/narrow profiles
- Don't get paralyzed by all the decisions and overthink it too much.
- If you are a risk taker go wide and plan that you may have to roll the openings and delete the chrome strips, and/or use wheel spacers to optimize clearance.
- It is easier to add a thin spacer than re-narrow the rear end housing !
- If you are conservative trust DSE guidance as mentioned and things will work just fine without much hoopla !
- Consider how long your build will take. If you buy fresh tires and wheels for your mock-up it is a big expense and they may be sitting in storage for a while !

Yes, a 12" wide wheel is possible on a 67' and 68'. Backspacing will depend on you axle length. Stielow's Mayhem had 12.0X19 (325/30-19) and also 12.5X18 (335/30-18), but he pulled, stretched and rolled the rear fenders.

Good Luck!

I have 315/35-17's on my 67 and haven't rolled the fenders. Even still I could easily go wider. Don't know the backspace as i ordered the rear (56") to set the wheels where I wanted them

thanks for all the help guys I really appreciate it!!!!