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paging doug or others: gear, rpm, speed chart?(5 posts)

paging doug or others: gear, rpm, speed chart?Dark Sonix
Jun 27, 2002 8:23 AM
a while ago, doug posted regarding lance's speed, calculating the gear and rpm's required to hold 34 mph, given a 700cc wheel.

is there a chart or formula that one could use to calculate pedaling rpm's, given speed and gear?

Thanks
Pure geometry ...Humma Hah
Jun 27, 2002 8:55 AM
Measure your wheel circumfrence. This step is required to set the calibration of your cyclecomputer, the answer is usually in the neighborhood of 200 cm (convert to whatever system of distance units you like). For each revolution of your wheel, you move forward that much.

Then multiply that amount by the ratio of chainwheel teeth to rear cog teeth. Let's say you ride 48:16, that's 3:1, or three rear wheel rotations for each crank rotation. So for each crank rotation, you move forward three rear wheel circumfrences.

After that, its all units conversion, working out pedal RPM to mph or kph, etc.
re: paging doug or others: gear, rpm, speed chart?Len J
Jun 27, 2002 8:59 AM
You can use a gear calculator to back into it;

Try
http://www.sheldonbrown.com/gears/

Plug in your chainrings & cassette & select what output you want uder gear units and see if this helps

Len
re: paging doug or others: gear, rpm, speed chart?grzy
Jun 27, 2002 9:21 AM
Cadence (RPM) x Fr. CR (teeth ) / Rear Cog (teeth) x wheel dia. (in.) x pi x (60 min./hr) x (1 ft./12 in.) x (1 mi./5280 ft.) = speed in mph

Note: CR/cog x d = gear inches
go hereTig
Jun 27, 2002 9:59 AM
http://www.analyticcycling.com/GearSelection_Page.html