I’ve got a 1968 XR7 that I recently replaced the entire real suspension on (shocks, leafs, shackles, hardware, and rubber components) because the rear tires were rubbing when anyone was in the rear. I’m trying to figure out if it’s better for me to change wheels so the offset in the rear tucks them in more (don’t want to go thinner than an 7” with 235 tires) or somehow raise the rear up. All opinions and help are appreciated. TIA.
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That all depends. Are you in love with the wheels? Were you considering changing them anyway? How old are the tires? Are they getting due for replacement? How often do you have people riding in the back?
It’s always best to get wheels and tires that fit. But I’m always the first person to never do that. Instead, I make the car and suspension fit the wheels and tires. That all starts with freshening up the suspension. You’ve already done that.
You could add another leaf to your springs that will make them a little stiffer and get you a little bit of lift without going to air shocks which a lot of people have nightmares about. You could also remove the rubber insulator pads between the springs and the rear axle to gain a little lift that way. Be careful on how much that could affect pinion angle and the factory wedges that were placed in there for that. I had my machinist brother make me a fresh set of 3 degree wedges.to place under the axle on top of the springs to compensate for that. Removing the rubber insulators also affects the U-bolt length that secure the axle to the springs. So that needs to be considered.
You need to answer the first paragraph questions and then decide from there.
Appreciate the response. Not sold on the wheels/tires at all. They’re fairly new but, the rubbing drives me nuts. I’d really hoped the suspension would fix it as the guy I bought it from assure me he “did all the math” lol. I don’t drive a lot with many passengers but, now that I have a second bay on the way, I’d like to have it ready to cruise with all four and not have the issues anymore. I’d be apprehensive on changing much of the rear bits besides possible addition of a leaf. I too heard drama with the bag setups. I really don’t know where to begin on adding a spring, though.
You could enlist a spring shop to add a leaf. Basically, you have to remove the pin that holds the stack together to add the leaf. That’s often easier with the springs out of the car, which you probably don’t want to hear, seeing as you just did all that. Since you’re not sold on the wheels and tires, maybe that’s the route you might lean towards. Replacing those with the right backspacing and tire sizes to make everything fit right.
I have to laugh at your previous owner who did the math.
And I know all about the airbag set-ups. I have them on two of my cars, Cougar included, and helped install them on three other cars in addition to my two.
Do you happen to know what backspacing I should start looking for so I can try not to have to disassemble the rear?
A safe bet on a stock suspension first gen like yours is a 4.5 inch backspace on an 8-inch rim. Any wider than 8” and you have to start getting more creative. Othesr can chime in on what they have. My set-up is so far outside the box that it really won’t help anybody.
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On my previous Cougar, I had 17x7 and 17x8 Legendary 10 spokes…the rears had 4.75” backspacing with 245s and I didn’t have any issue with rubbing.
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Perfect place to start. Thank you.
American Racing TT2’s 17x8 ET8.
4.81 backspace according the specs.
245/45 tires. Haven’t noticed any contact or rub anywhere.
Rear springs vary more than Texas weather so re-arched and new sets can be wildly different in ride height. The stock profile had the rear lower than we are used to seeing in magazines. If you look at the advertising materials from the years our cars were produced it is obvious the nose sits higher and the tail lower. Hot rodding encouraged lifting, shackle kits, etc, so we are accustomed to seeing the hind end up, but it is not original. Early Cougars have less clearance than the later models.
