Tires rubbing

[Goody]

73 swinger. When I bought it one of the front and rear tires would rub on the fender when turning or breaking hard at speed. Every thing looks right. I know shocks were changed and some jegs cheap rims put on. I was thinking maybe the offset on the rims is off because the tires are not overly wide. Thoughts? Is there a way to calculate wheel offset and know what it should be? Would a tire place be able to check it? Thanks

 

[72bluNblu]

If the tires aren't all that big, then you're probably right about the offset being incorrect. Especially if it's happening on both the front and rear wheels. It would be helpful to post the tire sizes, they should be right on the side of the tire. It would also be helpful to know more about your suspension and brakes. If you have "cheap wheels from jegs" then you probably have the larger 5x4.5" bolt pattern, do you know if you have the 73+ mopar disk brakes up front? And what rear axle you have? Those things change the track width of the car, so, it changes the wheel offset/backspace you need to keep the tires from rubbing.

Offset and backspace are related, and backspace is easily measured. This picture explains all the wheel specifications you need to know...

To get the backspace, if you take a wheel off the car and turn it over so the side that faces the car is up, all you have to do is measure from the outside lip of the rim down to the wheel mounting surface. So if you lay a straight edge across the rim (not the tire) and measure like this you get the backspace (5" in this case).

It may be even easier than that though, because most new rims have the information stamped or cast right into them. Same wheel as above, you can see it's labeled as a 17x9, and the box after "ET" has a 0 in it (it's a zero, trust me). So, a 17x9" wheel with a 0mm offset, which just happens to be a 5" backspace.

As far as the tire shop goes, they SHOULD be able to tell you that. But they may also tell you that you need to buy new tires and rims, since that's their business. And, if your tires are damaged from the rubbing interference, they may be kinda pushy about replacing them because it's a safety issue.

If you can get a little more information and post it here I can probably answer most of your questions. That way you at least have an idea what you're in for, before some tire shop tries to pressure you into a sale.

 

[A56]

I find it curious that just one front and one rear are rubbing if I understand your description. Same side? Can you see where and what it's rubbing on? These cars are damn near 50 years old and this one may have been hit if the rubbing is JUST on one side. Just a thought.

 

[72bluNblu]

I find it curious that just one front and one rear are rubbing if I understand your description. Same side? Can you see where and what it's rubbing on? These cars are damn near 50 years old and this one may have been hit if the rubbing is JUST on one side. Just a thought.

I mean, that's definitely a possibility but it wouldn't be the first thing I went and looked for.

If the wheels have the wrong offset and are putting the tires really close to the body it could also be that the car just sits a little lower on that side. Ride height can be really critical for tire clearance, and small difference in ride height can absolutely make the difference between the tires rubbing or not. It's really easy to have a car sit lower by a 1/4" on one side, especially with the torsion bar adjustment and old leaf springs. Heck it could be 1/8" low on one side (you'd never see it unless you measured) and the wheels are just barely clearing on the other side.

It could also be really simple, like the wheels are close all the way around but the route that the OP takes with his car is always the same and it rubs on the same corner every time because of the speed, banking, angle of the corner etc. If there's a downhill corner with a little off camber road grading in one direction it could easily be the only corner that causes rubbing, and it would always be the same side. Lots of possibilities.

 

[A56]

I mean, that's definitely a possibility but it wouldn't be the first thing I went and looked for.

If the wheels have the wrong offset and are putting the tires really close to the body it could also be that the car just sits a little lower on that side. Ride height can be really critical for tire clearance, and small difference in ride height can absolutely make the difference between the tires rubbing or not. It's really easy to have a car sit lower by a 1/4" on one side, especially with the torsion bar adjustment and old leaf springs. Heck it could be 1/8" low on one side (you'd never see it unless you measured) and the wheels are just barely clearing on the other side.

It could also be really simple, like the wheels are close all the way around but the route that the OP takes with his car is always the same and it rubs on the same corner every time because of the speed, banking, angle of the corner etc. If there's a downhill corner with a little off camber road grading in one direction it could easily be the only corner that causes rubbing, and it would always be the same side. Lots of possibilities.

Well, it's just a thought and all it takes is to LOOK, can't be that challenging to take a knee. I wouldn't be removing wheels and measuring first. AND it's one front wheel and one back wheel. Not all four. Different strokes.

 

[72bluNblu]

Well, it's just a thought and all it takes is to LOOK, can't be that challenging to take a knee. I wouldn't be removing wheels and measuring first. AND it's one front wheel and one back wheel. Not all four. Different strokes.

Right, and if one of the rear springs is high then the opposite front corner is low.

He already knows he has cheap jegs wheels on it, more than likely they're 0 offset which isn't right for an A-body. If you hear hooves, you should think horses not zebras. Unless maybe you're in the Sahara.

The wrong offset wheels can cause his exact issue. Body tolerances on these cars were over a 1/4" from the factory. Tires on opposite corners rubbing because the wheels have the wrong offset is par for the course.

 

[A56]

Right, and if one of the rear springs is high then the opposite front corner is low.

He already knows he has cheap jegs wheels on it, more than likely they're 0 offset which isn't right for an A-body. If you hear hooves, you should think horses not zebras. Unless maybe you're in the Sahara.

The wrong offset wheels can cause his exact issue. Body tolerances on these cars were over a 1/4" from the factory. Tires on opposite corners rubbing because the wheels have the wrong offset is par for the course.

Whatever.....

 

[72bluNblu]

Whatever.....

Geez man. Someone installed cheap wheels. Cheap wheels are usually 0 offset. It's the most obvious issue.

And, you can't do a good inspection of the suspension and chassis by "taking a knee". A collision that effected opposite ends of the car would mean checking all the frame rails for buckling. Can't do that on a knee with the car on its wheels. Pulling a wheel is a piece of cake. And if you want to actually check the suspension, you'll have to pull the wheels anyway. You can't see enough of the suspension to actually check anything with the wheels on and the car on the ground.

 

[A56]

Geez man. Someone installed cheap wheels. Cheap wheels are usually 0 offset. It's the most obvious issue.

And, you can't do a good inspection of the suspension and chassis by "taking a knee". A collision that effected opposite ends of the car would mean checking all the frame rails for buckling. Can't do that on a knee. Pulling a wheel is a piece of cake. And if you want to actually check the suspension, you'll have to pull the wheels anyway. Can't see enough of the suspension to actually check anything with the wheels on and the car on the ground.

Get over it, good grief..... I don't need 8 more paragraphs of your thinking.

 

[72bluNblu]

Get over it, good grief..... I don't need 8 more paragraphs of your thinking.

You didn't need my thinking at all, this isn't your thread and I'm not trying to help you.

The OP has a minor tire rub. A bent chassis is literally the last thing to look for. The first thing is the cheap aftermarket wheels. This is not hard. Neither is pulling a wheel.

 

[A56]

You didn't need my thinking at all, this isn't your thread and I'm not trying to help you.

The OP has a minor tire rub. A bent chassis is literally the last thing to look for. The first thing is the cheap aftermarket wheels. This is not hard. Neither is pulling a wheel.

I made a comment to the op, not YOU. YOU decided to say that YOU wouldn't do it my way. I'm allowed an opinion OTHER than yours. YOU went on a book writing tour and you weren't just addressing the op. So here you are after your nap, back at me again. You win. UNCLE !!