wearyourtruth
11-19-09, 12:22 PM
is there a formula or program that allows me to convert my mph to rpm based on my gear ratio? or vice versa. just curious really but i haven't found anything online.
Singlespeed & Fixed Gear - formula/program for converting speed to RPM and vice versa?
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adriano
11-19-09, 12:39 PM
diameter(mm)*pi*rpm*60/1609344
ismellfish2
11-19-09, 12:44 PM
There's this thing called Google... took me about 7 seconds.
JiveTurkey
11-19-09, 01:00 PM
http://sheldonbrown.com/gears/
Set to "MPH @ 100 RPM" (or "KPH @ 100 RPM"). Once you know your speed at 100 RPM, it' pretty easy to calculate your RPMs at other speeds.
E.g.: If 15 MPH = 100 RPM, then new RPM = [X/15 * 100], where "X" is the new speed.
If your new speed equals 16 (meaning, "X"), then your new RPM = [16/15 * 100] = 106.7 RPM.
Set to "MPH @ 100 RPM" (or "KPH @ 100 RPM"). Once you know your speed at 100 RPM, it' pretty easy to calculate your RPMs at other speeds.
E.g.: If 15 MPH = 100 RPM, then new RPM = [X/15 * 100], where "X" is the new speed.
If your new speed equals 16 (meaning, "X"), then your new RPM = [16/15 * 100] = 106.7 RPM.
paktinat
11-20-09, 02:02 PM
http://software.bareknucklebrigade.com/rabbit.applet.html
teedoff087
11-20-09, 02:11 PM
Yeah ^^^ What he said. Rabbit does exactly what you want. You can also download the applet so you don't have to go to that webpage every time you want to calculate.
http://software.bareknucklebrigade.com/ (click "Outside Browser")
http://software.bareknucklebrigade.com/ (click "Outside Browser")
DMF
11-20-09, 05:20 PM
is there a formula or program that allows me to convert my mph to rpm based on my gear ratio? or vice versa. just curious really but i haven't found anything online.
RPM of the wheel? Or RPM of your feet (cadence)?
If RPM of the wheel, then gear ratio is completely irrelevant. See adriano's formula (which appears to be correct).
If RPM of your feet, it's only slightly more complicated. You'll need to use gear ratio to determine wheel RPM.
RPM of the wheel? Or RPM of your feet (cadence)?
If RPM of the wheel, then gear ratio is completely irrelevant. See adriano's formula (which appears to be correct).
If RPM of your feet, it's only slightly more complicated. You'll need to use gear ratio to determine wheel RPM.