# Measured Mile?

**URL:** <https://boards.straightdope.com/t/measured-mile/320458>\
**Category:** Factual Questions\
**Created:** [September 7, 2005, 2:16am UTC](https://boards.straightdope.com/t/measured-mile/320458 "2005-09-07T02:16:10Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![Oregon\_sunshine](https://avatars.discourse-cdn.com/v4/letter/o/50afbb/32.png) [@Oregon\_sunshine](https://boards.straightdope.com/u/Oregon_sunshine)\
**Post date:** [September 8, 2005, 1:08am UTC](https://boards.straightdope.com/t/measured-mile/320458/21 "2005-09-08T01:08:31Z")

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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.

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**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\
**Post date:** [September 8, 2005, 1:49pm UTC](https://boards.straightdope.com/t/measured-mile/320458/22 "2005-09-08T13:49:07Z")

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> [@Balthisar](#):
>
> Wow, I never thought it made that big a difference, so I calculated the following:
> 
> ```auto
> 
> 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!

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**Author:** ![Balthisar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/balthisar/32/2825_2.png) [@Balthisar](https://boards.straightdope.com/u/Balthisar)\
**Post date:** [September 8, 2005, 2:52pm UTC](https://boards.straightdope.com/t/measured-mile/320458/23 "2005-09-08T14:52:11Z")

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> [@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:

```auto

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 :).

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