Wheel/Tire help for 68 notchback barracuda

Just a bit of info on tire sizes, using theoretical numbers for reference only...

The numbers that designate the tire size can be read as such..

First number)- "255"= the width of the tread in millimeters, or 255mm
Second number- "60"= the height of the tire sidewall in relation to the tread width, in this case 60% of 255mm
Third number- "15"= the rim size, or 15" in this case

So, you want to fill up the wheelwell?? You need to consider the maximum width of the tire you can run according to the backspace of the rim and rim width. To measure backspace, place a straightedge across the back lip of the rim and measure down to the flange that sits on the drum, voila, your rim backspacing. Now measure from the front edge of the drum where the wheel would mount to the point where a tire or rim would rub against the leaf spring, voila, the maximum backspacing you can run.

Now, to find the maximum width rim you can run, do just the opposite. Measure from the front of the drum to the edge of the wheel lip and add that number to your backspacing, and voila, maximum rim width!! Now, you need to make amends for the fact that the tire will stick out past the rim lip, and need to decrease your rim width by about 1" on both sides. Now, take your desired rim width to your tire store and ask what is the widest tire you can run on that rim, then calculate the height of the tire according to the first number of the tire as suggested above.

If you want to run 15" tires, you're simply gonna have to buy aftermarket wheels with the 4" bolt pattern, which are very hard to find in 5 spoke and Klassic, unless you can use the uni-lug design. You may find that spacers are your only option, but research will surely turn up more answers on this!!

Good luck with your project, hope this helps a little!! geof