RPM and MPH for Dummy Cyclists

Cycling cadence sensor

It's long been obvious to our research staff here at the Antisocial Network that many a freelancer's claim to be an "expert" in their topic is not worth the pixels it's printed on. Take for instance Alberto J. Medina, who according to his bio at LiveStrong.com is an "ACE-certified advanced health and fitness specialist... health coach and group fitness instructor." Despite a BS in "exercise and health promotion," however, it appears he knows little or nothing about cycling (lots about "grunt-and-fart," though, we suspect). We figured that out based on his post, "How to Convert MPH & RPM When Cycling."

We based our disdain for Medina's cycling expertise on the level of bogosity in his opening statement:

"The relationship between miles per hour (MPH) and revolutions per minute (RPM) is useful for learning how to pace when cycling. Many stationary bikes and outdoor bikes have technology that provides metrics. However, you may find it necessary and helpful to manually convert between MPH and RPM readings."

We defy Alberto J. to show us an "outdoor bike" with a technology that shows wheel RPM. Additionally, it's pretty obvious that Medina thinks people want to somehow convert speed to cadence, at least based on his last line:

"To calculate pedal RPM you must know your bike's gear ratios."

Well yeah, but most cyclists who worry about their cadence know that you can buy cadence sensors, either standalone or as part of a cyclocomputer. That's hella easier than moving "between MPH and RPM with one-step arithmetic," especially Alberto's version of arithmetic. According to him, you have to measure your wheel "from the center... to its outside edge." HINT: No, you want to measure the circumference of the mounted tire (or better yet, look it up). Next, you calculate circumference...

Alberto then tells you to "Divide 1056 by the circumference of the wheel. The quotient is your bike's conversion factor for moving directly between MPH and RPM." We have no idea whatsoever where Medina came up with this conversion factor. It's not in the sole reference – a blog about radio-controlled cars – we found in an archived version of his post. To be perfectly honest, we have no reason to doubt that the trick for calculating a conversion factor is bogus: even the greediest freelancer wouldn't go through the effort to make up bull like that. On the other hand, it's pretty obvious that the number 1056 is units-dependent. Yet Al never mentioned whether you measure your wheel in feet, inches, millimeters... It looks to us like it's only valid for a circumference in inches, but who knows?

Based on his lousy, incomplete information and his obvious unfamiliarity with the topic he wrote about, we do hereby proclaim Alberto J. Medina to be the Dumbass of the Day. So there.

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DD - CYCLING