[locomotivebreath]

Here’s the right front tire forward edge . About 3/4 ish clearance with copper 215/65/15s . Rear edge is just a tad more . Car is lowered about an inch and all suspension and bushings are new .

[ts3189]

Measured the rims today 15x7 4 inch back space didn’t really seem like bushings were bad. Any good way to check with wheel off?

[nytrainer]

In addition to other possible factors mentioned I’ll add that I run 15 x 7 Rally 2 on 68 convertible (Lemans) with 225 70-15 and have no rubbing. IIRC the wheels are stamped KS. A friend with same car (not convertible) with my wheel/tire had tire rub issues but he has disc brakes up front and I have drums. I think I read somewhere that the disc setup has a slightly wider width overall on front measurement (1/2 in?) which can contribute to tire rub. What brakes are you running?

[ts3189]

Disc on front. Believe the wheels are aftermarket also. The 4 inch backspacing isn’t helping..think I will order the 225-60-15 diamondbacks on Monday.

[locomotivebreath]

Keep in mind , 225/60/15 is a short tire .

[ts3189]

The 235 60 15 is 26.1 inches the 225 60 15 is 25.6. The width is 8.9 vrs 9.3 on the 225.

[b-man]

The 225/60s will look tiny in the front and even worse in the rear. Even the 235/60s are a little short.

Your rubbing problem is likely because your wheels have only 4” of backspace as compared to factory 15x7s that have around 4-3/8” to 4-1/2” of backspace. The wheel being pushed out by half an inch makes a big difference.

The only way you can get away with short tires in the 25” range is to lower the car a little to help fill up the space in the wheel openings.

I’d be looking into a set of factory 15x7s and run at least a 235/60 in front and 245/60 in the back, or at least 235/60s all around if you like rotating your tires.

It makes absolutely zero sense that the supposed copies of Rally II wheels available from the aftermarket aren’t manufactured to factory backspace dimensions. Unfortunately this is true for most every style of 15x7” aftermarket wheel available for our cars, 3-3/4” backspace is common and limits the tire size to the point where they’re almost unusable.

[locomotivebreath]

My 215/65’s are 26 . I wish they were taller to fill the well out a little more . I really wanted the 215/70s at 26.6 I believe but I chickened out because of the slightly wider tread . I think now that I could’ve gotten away with it .

[rasilverbird]

If you are only rubbing when in reverse, then I'd say something is loose. Replace the control arm bushings and see what happens. Can't hurt if they're old.

[ts3189]

Agree b-man the backspacing is the real issue along with the wider tread in front. I have ordered the 225-60-15��

[b-man]

Originally Posted by ts3189

68 Gto 235 -60-15 tires rub when backing into driveway. Need new tires have 14 inch and 15 inch rims available. Ordering new diamondbacks to replace whats there, looking for recommendations ?

Which 14” wheels do you have available?

If you have some original 14x6” wheels a set of 215/75-14s at 26.7” tall or a set of 225/70-14s at 26.4” tall would be pretty much a slam dunk on fitment, not to mention give you a more factory correct look.

Keeping the 15x7s and compromising on tire size by going 225/60 isn’t what I’d recommend but it’s your car and your choice.

[ts3189]

B-man will check codes on 14 inch tommorrow believe they are 14-7 from 85 or so grand am

[b-man]

Originally Posted by ts3189

B-man will check codes on 14 inch tommorrow believe they are 14-7 from 85 or so grand am

If so they would also have close to 4-1/2” backspace and be a better fit than your current 15” wheels.

Available tire sizes are limited these days for both 14 and 15 inch but the sizes we need to fit stock 6 or 7 inch wide wheels are available.

[locomotivebreath]

Of course all measurements vary by manufacture ::
G70-14
- 26.8 diameter
- 6.9 tread with
- 8.8 section width
P215/70/R15
- 26.7 diameter
- 7.0 tread
- 8.7 section width
- I think the 215/70/15 would get by with disc brakes and repro rally’s based off my pic above . I wish I had the taller tire just for the extra ground clearance .

[ts3189]

The 14 inch are code kx with 3 1/2 inch backspacing.

[b-man]

Originally Posted by ts3189

The 14 inch are code kx with 3 1/2 inch backspacing.

14x6” wheels, correct?

[ts3189]

Yes sir, they are 14 -6 3 3/4 backspace code kx

[b-man]

Those will be a good fit with either 215/75 or 225/70 tires.

The 70-series will be more performance-oriented than the 75-series tires.

It just makes more sense for a pleasure cruising car to run one of those 14” sizes than to compromise and run short 15” tires to make those 15x7s with 4” of backspace work in my opinion.

If you want to stick with 15” wheels and run wider 60-series tires then you’ll have to get some with more backspace, there’s just no way around that.

I’m using 215/75-14s on my own ‘64 Le Mans convertible on 14x6” Hurst wheels (3.825” backspace) and they’re more than fine for what I’m expecting from an old stock suspension Pontiac.

Sorry I don’t have a ‘68 to show as an example but you get the idea. The shape of the front wheel openings on ‘64-‘65 are similar to a ‘68-‘69 the way they pinch inward at the bottom.

[ts3189]

Thanks bman . So not issue with the 3.75 backspacing ? Or disc brakes with those wheels? If not I will go with the 225-70-14🤞

[b-man]

Well the stock wheels your car came with should be close if not the same dimensions as your 14x6” wheels.

Perhaps someone here can confirm the backspace measurement on their original 14x6” ‘68 GTO wheels. Pretty sure the last time I checked one of my 14x6” steel disc brake or drum brake wheels the backspace was 4”.

It’s easy enough to check for disc brake clearance by slapping one on but I can’t imagine there would be any issues.

The outer edge of your 15x7” with a 4” backsplace will be 3/4” further to the outside than a 6” wheel with 3.75” backspace, so you’ll be tucking the outer edge of that 14x6” in by that amount.