Track Cycling: Velodrome Racing and Training Area - Chart Wanted: Cadence @ a Certain Speed..?
Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.
Dave Noisy
11-04-04, 08:02 PM
Hi all, i'm sure there's gotta be something like this out there..
I'm looking for a chart which shows what gear you need to be in to maintain a certain speed at a certain cadence.
For example, if i wanted to ride ~40kph and spin ~100rpm while at that speed, what gear would i need to be in?
Thanks!!
Not sure how scientific this is because it doesn't take into account weight of rider, flat vs. hills, etc. But I find it pretty useful to get the proper shifting sequence.
http://www.panix.com/~jbarrm/cycal/cycal.30f.html
Man, I can't find it any more, but there's a forum that's all track bikes. I think that there was a chart here that listed gear vs cadence vs speed vs time per lap on different length tracks...
Map tester
11-04-04, 08:31 PM
Try this: HPV Drivetrain Analyzer (http://www.soulbikes.com/gears/) or Sheldon Brown's Gear Calculator (http://www.sheldonbrown.com/gears/)
Dave Noisy
11-06-04, 12:44 AM
Thanks guys, the Panix and Brown's ones are great!
HereNT - you prolly mean http://www.fixedgearfever.com/ - i'm on there as well, thanks!!
For the math unchallenged here's how to figure it out:
the chain ring to rear cog tooth ratio is the gear ratio which means that for every turn of the crank the rear wheel turns front ring # teeth/rear cog # teeth times more. This ratio is then multiplied by the wheel circumference which you remember from geo as 3.14159 x the diameter (most wheels are 700mm(27.56 inches) or 27 inches). Therefore, multiple the 3.14159 x 27 x tooth ratio x cadence and that's your speed in inches per minute. To convert to mph multiple that number by 60/(12x5280).
Example: riding a 42/17 at 100 cadence on 27" wheels (if you ride 700's or other sizes just change to whatever diameter you have on the rear wheel
100 x (42/17) x 3.14159 x 27 x 60/(12 x 5280) = 19.84 mph
A mental exercise I used to do while training was simply scale the speed by the gear ratio knowing that a 42/17 or 66.7 inch gear is 20 mph at a 100 cadence. If I was riding a 52/14 which is a 100 inch gear than my speed would be close to 1/2 x faster or 30 mph. These were the days just before inexpensive speedometers were available ;)