Measured Mile?

[Oregon_sunshine]

They help your morale when you’re driving, say, I-80 through Wyoming…otherwise, most of it would be endless (beautiful, but endless… and lonely) rocks, crags, and sage shrubs.

The mile markers were the only way my sanity (what there is left) survived.

[robby]

@Balthisar

Wow, I never thought it made that big a difference, so I calculated the following:

diameter, in            28          30          34
circumferance, in       87.9645943  94.24777961 106.8141502
Rps                     1000        1000        1000
Rpm                     60000       60000       60000
distance per minute, in 5277875.658 5654866.776 6408849.013
miles per hour          83.29980521 89.2497913  101.1497635

And was suprised to see the big difference this would make using what I guess are probably reasonable truck tire measurements.

Your calculations are off, Balthisar.

A 28-inch diameter tire rotating at 1,000 rotations per second (60,000 rpm) would indeed be traveling linearly at 5,277,876 inches per minute, but this corresponds to 4,998 miles per hour!

[Balthisar]

@robby

Your calculations are off, Balthisar.

A 28-inch diameter tire rotating at 1,000 rotations per second (60,000 rpm) would indeed be traveling linearly at 5,277,876 inches per minute, but this corresponds to 4,998 miles per hour!

Wow! That’s rather embarrasing. If for nothing else, you’d think the 1000 revolutions per second on the tires would be clue, right? Here are revised calculations:

diameter, in                  28         30          34
circumferance, in             87.96      94.25       106.81
Rps                           15         15          15
Rpm                           900        900         900
distance per minute, in       79168.13   84823.00    96132.74
miles per minute              1.25       1.34        1.52
miles per hour                74.97      80.32       91.03

Still, it’s a significant speed change. If I have them wrong this time, I give up :).