Well you can definitely get at least 215 on there, because that's what I run. If you have the right backspacing you could probably get more but then you would be into fender-rolling territory. Check out dodgestang's tire fitment chart and that will give you a good idea of what you can and can't do.

 

Probably no help but with a 70 Mach 1, I run:

rear BFG 275/60R15 (section 11", tread 9") only had to modify sway bar.

front BFG 235/60R15 (section 9.5", tread 7.5)

nothing rolled, just banged up a bit from years of just plain old fun.

tried my spare 245's in the front, but with Shelby drop and with part of the springs lopped off, its just a tad to low and rubs a little on u-turns or BIG bouncing L/R turns. may put stock height springs back on with roller perches and try my spare 245's again. soften the ride and add as much "stout" as I can.

 

I just put tires on my 67' this past summer, 17" 235 in front and 245 in back. I have NPD 1" lowering coils and no rubbing.

 

I currently have 235/60R15 on all four corners on my 66. I know that next time I get tires though, I'm doing 225, 215, 205.

 

What size rim? What style suspension front/back? Wheel well trim? Stock Fender lips? Rolled fender lips?

You can go pretty big on a 68 without flares or spring relocation....just takes a little patience, work in a few areas, and the right wheels

 

Wheel diameter would be good to know. We're gonna need more info.
On an unmodified '68 I've run 225-50-16's in the front. Just the alignment
set, nothing else done. Stock 289 ride height, etc. The ride height is the
only reason it works.
I've also run 225-55-16" fronts with GW arms. That's a huge tire because
of the height & width. At a 1.25" drop, it fills the wheel opening.....
I had to baseball bat roll the front lips too.

ex-Global West GM
1991-1995

 

Sorry, 235/45/17 and the rim is 17"*8"

 

Just Do It Already!

 

On 17's? No way. Mine are rolled with 215/50/17.

 

Uhhhh.....

245 40 17 front/255 40 17 rear - lips rolled )4.75 backspace 0 camber

235 45 17 front/275 40 18 rear - lips rolled 4.5 backspace 0 camber

235 45 17 front/275 40 17 rear - lips not rolled 4.75 backspace -.05 camber

 

I have 245/45r17 with 4.5" backspacing on an 8" wheel. It rubs on the bottom front of the fender flare with the wheel cranked. More negative caster might fix this however. I've done 234/45 17s before with now rubbing. My car is lowered 1.5" in the front.

 

I run a 235/45/17 on the front of my '65, 17x8 wheels with 4.75"BS, you should have no problem on a yours. Unless of course its slammed to the ground.

 

Fronts: 17x8, slightly rolled lips on stock fenders, 1" spacer.

Rears: 17x8, no rolled lips on rears, no spacers.

I run 255/40/17 on all 4 corners.


**I've test fit 275's in back on a 17x9 wheel and it clears the leaf spring about 1/2"-3/4", and that's without any spacer. That was with a stock 1968 8" rear end. I bet you could stuff a 315 with the right spacer. 255 is about the very max in the front with stock suspension.

 

Check out Dodgestang's Tire and Wheel Chart

Here's the link:
http://www.dodgestang.com/Tire Fitment Guide 67-8.pdf

 

i have 235x60x14 on my 67 coupe wheels are from an aussie ford 4 inch backspacing

 

I had 225-50-15's and now have 225-45-17's in the front, 66 Mustang