[MYLAR6126]

I just purcahsed a restored 1970 Mach1, 351 cleveland, 4V, fmx, 3.00 traction lok rear. Car has 15" magnum 500 wheels and 225/60x15 on the front and 245/60x15 on the rear.

Previous owner did not drive the car often and garaged it sitting on a concrete floor.

Car starts to vibrate at about 75 mph and goes away when speed drops back.

Yesterday I took it to my local Ford dealer to have the tires balanced. The tech. tried to explain that one front and one rear tire was the problem from sitting on the concrete floor and that balancing would not correct the problem. He said the problem MAY correct it's self after driving several hundred miles. He said the tires were still safe but would cause the vibration at higher speeds.

I told him I planed to store it over the winter and he suggested to put a few pieces of carpet between the tires and concrete floor and try and move it at least once a month.

Has anyone else run into this problem? Maybe I should just replace the 2 tires.

ALSO.... the car did not have a spare tire. I tried to find a basic black steel wheel 15x7 but I find different bolt patterns and offset.

Anyone know where I can find a wheel and what dimensions I need to match the wheels already on the car?

Thanks for any help.

Bill

[Jay H 237]

Sounds like the tires have flat spots from sitting. He's right that the problem may go away or it won't. Depends on if driving the car will "massage" the tires enough so it evens out. Replacing the tires would be an immediant fix. If you're not going to drive the car over the winter I would leave the tires for now. Moving the car around evey so often would help this problem from forming. The carpet gives a little "cushion" under the tires. That's also why some people put thier cars on jackstands when in storage.

I would also overfill the tires slightly, about to 40 psi, while you're not driving it on the road. This is also another trick to help stop flat spots from forming.

As for the wheel I don't know off hand what the offset is for 1970 or which offsets would work. You could take off a wheel and measure it as it would be your best bet.

I bought wheels (14") as 'rollers' for when my car goes for paint. I got them from a salvage yard. I know 2 are from a 1995 2 wheel drive Ranger, and one of the others is off an Aerostar, don't know what the 4th came from. If you only want a basic rim for a spare then a salvage yard would be your best bet and they should know what would fit depending on disc or drum brakes also. If you want a matching Magnum 500 rim then the Mustang suppliers would have it.