Do bigger wheels put less miles on your odometer?

Factual Questions
21

There’s two ways to adjust the speedometer to compensate for oversize wheels and tires.

The speedometer cable has a “drive” gear on the end that inserts into the transmission; it engages a gear on the output shaft of the transmission. You can change the size (number of teeth) of the speedometer cable gear; typically it’s held on the cable by a little clip. The rule of thumb is that a change of one gear tooth on the drive gear(say, from 17 to 18) changes the speedometer by 4 miles/hour.

The second way, if changing the drive gear won’t get you there (no replacement gears available in the size you need)is to have a speedometer shop make up a little gearbox to go between the cable and the speedo. I had this done on my Hudson many years ago, and it worked great.

22

Oh yeah. This reminds me of a guy who I used to know. Had a daughter commuting to college 60 miles away. He just flat-out DISCONNECTED the vehicle speed sensor in the car she drove for a few months at a time, and taught her to judge speed by RPMs in this (manual) vehicle.

23

The center of the wheel is moving at the same speed as the car all of the time.

A point on the periphery (on the tread) moves at zero speed when in contact with the pavement and increases to a bit more that the speed of the car when at its highest point away from the pavement.

All points on the wheel trace a path known as a trochoid.
“A curve traced by a point on or connected with a circle as the circle rolls along a fixed straight line.”

“Beware of the Cog”