still need help

[68bird400]

Im Getting Mixed Responses Regarding Maximum Wheel And Tire Size On A 68 Firebird With 2 Inch Drop In The Front 1.5 In Theback. What I Want Is 17x8 In The Front And 18x 9.5 In The Rear, Which I Have Been Told Should Be No Problem. On The Other Hand Im Hearing 17x9.5 Is The Biggest I Can Go Out Back. Id Like To Do Everything Possible Without Mini Tubbing...help?!

[BA.]

I can't imagine why someone would say you cannot do 18x9.5 in the back but you could do 17x9.5 out back. I mean, it's the tire width and height that will be the ultimate factor isn't it? (with the parameters being those two rim sizes, and only for the rear)

[Clsccmro]

Im Getting Mixed Responses Regarding Maximum Wheel And Tire Size On A 68 Firebird With 2 Inch Drop In The Front 1.5 In Theback. What I Want Is 17x8 In The Front And 18x 9.5 In The Rear, Which I Have Been Told Should Be No Problem. On The Other Hand Im Hearing 17x9.5 Is The Biggest I Can Go Out Back. Id Like To Do Everything Possible Without Mini Tubbing...help?!

You can definitely fit an 18x9.5 out back. However, it really depends upon the tire you choose. If you choose too large of a diameter tire for either a 17 or 18 inch wheel, you will definitely have problems. My 69 camaro has 18x10's with 285/30/18 tires, with rolled lips and a little massaging (bfh) of the inner wells. My tires fit just right, but if I would have went with a tire size of 275/40/18 it would have been way too tall. By the way, a little helpful hint in this area:

Here's the little equation to figure out the height of the sidewall:
(a 275mm width tire with a 40 series profile)
275 x .40 = 110mm 110mm / 25.4 = 4.33 in.

Total: 4.33in (height of tire sidewall on each side of rim)

Most likely this size tire will not work on your application. So, you see my point, you need to choose the right tire to allow the 9.5in wide rime to work. Since the rim is so large, it pushes the boundaries on the outter edge of the wheel well and the inner edge as well. The rear quarters are angled inwards starting at the wheel well lips, and the closer you get to the lip, the harder it gets to run a higher profile tire.

[jy211]

I have a 2" drop in the front on my camaro and a 3" drop leaf set up from DSE. I am running 18x8 fronts and 18x9.5's in the rear. I think I have a 275/30 rear tire and I only very slightly scrap on the drivers side on a hard bump. But I used to scrape when I had 15" welds and the car wasn't lowered. I bought the fender lip rolloing tool so that should take car of the scrape.