backspace?? 67 firebird

[ricer]

So i have done some rough measurements and just wanted to see if i am overthinking this or not. (so really more of a confirmation than ??)

Car is a 67 firebird mini tubed, with springs moved inwards similar to the DSE mini tub kit. The wheels i want to run are 17x11 with a 325/45 tire. stock width axle

I measured from the flange face to the spring since that is the first "obstruction" and i come up with roughly 9". From the flange to the fender lip i have roughly 5". Going from 10 o'clock, noon, to 2 o'clock i have anywhere from 13-15-13" from wheel well to fender (so actually slighltly less to truely work with).

the tire has a section width of 12.6 and fluff that up a little to take into account the outside lettering etc that they leave off and spacing around it i figure on 13" of tire space that is needed.

So with a 17x11 if i run 6.5 BS that should leave me 1/2 from the lip and a couple inches from the spring. My options on BS are 6.5, 7.5, 7.75.....so my other thought was to get the 7.5bs and run a spacer to "fine tune" the wheel spacing in the wheel well.

After finding the wheels i want and going over and over the BS/measuring stuff in my head i am starting to second guess myself and just wanted some outside opinions.

[DEIGuy38]

Originally Posted by ricer

So i have done some rough measurements and just wanted to see if i am overthinking this or not. (so really more of a confirmation than ??)

I measured from the flange face to the spring since that is the first "obstruction" and i come up with roughly 9". From the flange to the fender lip i have roughly 5". Going from 10 o'clock, noon, to 2 o'clock i have anywhere from 13-15-13" from wheel well to fender (so actually slighltly less to truely work with).

the tire has a section width of 12.6 and fluff that up a little to take into account the outside lettering etc that they leave off and spacing around it i figure on 13" of tire space that is needed.

So with a 17x11 if i run 6.5 BS that should leave me 1/2 from the lip and a couple inches from the spring. My options on BS are 6.5, 7.5, 7.75.....so my other thought was to get the 7.5bs and run a spacer to "fine tune" the wheel spacing in the wheel well.

An 11" wheel is actually 12" wide, so if you have a BS of 6.5 on an 11" wheel you have a front spacing of 5.5. You said you only had roughly 5" from flange to fender lip, so this will not work. According to the notes on my 68 camaro the width of the stock rear with disk brakes was 60.5". Inside of qtr to inside of qtr was 69.5" at 12 oclock. 69.5-60.5=9" divided by 2 = 4.5" of front spacing on each side with 0 clearance. My qtr lips were 1" wide, cut .5 out and roll the lips for clearance. That would put you needing the 7.75 BS. Measure 3 times before buying. Make sure you will be satisfied with the look of the wheel before purchasing. If not run the backspacing you like then narrow the rear. It is expensive to do it twice, ask me how I know. Good luck

Guy

[ricer]

yeah that is my issue, i am trying to make sure it will all work out the first go around.

Glad you mentioned the extra width in the rim b/c i completely forgot about that