Packard Forum Index » V-8 (1955-56)

I had a speedo error when I went to steel belted tires. After looking at the process of removing the speedo I went with the option of installing one of the gear box adjusters.

Don't remember how much it cost, but I think it was in the $100 range which included a short pig tail cable. It took longer to jack the car up than to install it.

If changing tires caused a significant speedometer error, you've also changed your engine speed at any given road speed. Most older cars can benefit from larger diameter tires, within reason. Larger than stock diameter tires will cause the speedometer to read slower than the actual road speed. Smaller diameter tires will do the opposite.

Even P235/75R15 radials have more revolutions per mile than the original 8.00-15's. It's significant. Those are the tires that mine has and my speedometer is off about 12%.

Reasons to not have radials. I've driven these cars on both radial and bias. I prefer the latter.