Vibration between 50-60 mph

[Anbele]

So I get the front car to vibrate/shake between 50 and 60 mph. Nothing before and nothing after. Wheels have been balanced. Guibo, center bearing and u-joints replaced. Alignment? Drive shaft? Any ideas?

[18Fiatsandcounting]

Does it vibrate when coasting, or only with your foot on the gas? If it vibrates when braking, it's a warped brake rotor(s).

If the vibration is coming from the front, it's almost certainly a wheel issue. Raise up the front wheels and spin each one by hand as fast as you can, and look for a wheel that wobbles a bit. Loose wheel bearings in the front? Could also be a steering mechanism issue like loose tie rod ends, or bad ball joints. Have the front suspension checked for issues (you can also do this at home).

Finally, some tires have issues despite being balanced. Try swapping the wheels/tires around from front to rear and see if that helps.

-Bryan

[TX82FIAT]

I think 18fiatsandcounting is on to something with the tires. Even a balanced tire can have flat spots from being parked for a period of time or hard braking. If the wheels lock up into a skid you will most likely develop a flat spot. Just sitting in a garage for several months can develop a flat spot. Under inflated tires can have this effect as well. it is very typical that a tire causes this vibration at a certain speed and not at others.