kennj123

here's a really good video about turning a regular bike speedometer into a cadence meter:

https://www.youtube.com/watch?v=qrL476g662I

it involves using a less than 10$ bike speedometer, improvising a magnet on the crank then enter a wheel diameter so the speed shows as X.Y revs per minute, so you multiply by 10 to get RPMs. The problem is i have both a wired and wireless computer but the wire isn't long enough to mount the sensor at the crank and put the display on the handle bar and the wireless doesn't have the range. The display pretty much needs to be on the handle bar to keep it from getting knocked around and because the decimal place on the display is rather small. I could buy one of the cheaper cateyes, but i need three of them for my bikes, plus i have a bunch of other people interested in biking that are watching what i do so the cheaper the better. Also, the cateyes for some reason make the speed number really big and cadence small, so its not really easy to see. It makes no sense to me at all, i grew up on a farm, all the tractors have tachometers because rpms matter, who cares about speed unless your breaking the speed limit. Tachs are critical for anything that has manual gearing. do the people who make bike parts actually ride bikes?

fietsbob

Simpler to just buy up range enough and it would be included. only 1 input and its only ticking off wheel rotations

2nd input and it s second sensor will count cadence.

really cheap? count how many times your foot goes down in 15 seconds, multiply by 4.

John_V 

If you want cadence and you don't really care about tracking it or posting it to a cycling log or web site, you can just download a free metronome app to your smart phone. Set a beat rate and synchronize your pedaling to the beat to get your cadence. Can't get much cheaper than that.

kennj123

metronome is interesting, i'll try it, but i'd also like a solution that is independent of a smart phone. sometimes i don't take it due to rain and heat. and sometimes i just don't want it with me because i don't want bothered.

caloso

Just as cheap and simpler: count for 60 seconds, multiply by 1.

kennj123

whats really annoying is even the purpose built cadence monitors put cadence at a really small text size but speed is really in your face big size. Converting a speedometer like in the video is nice because you just have to look for the 9. I put one on my exercise bike just like the video says.
The problem with counting is I have my mind on alot of other things, like traffic and how much pressure i'm putting on my knees, is it enough to get the work out i want without causing knee problems.

fietsbob

... if you dont lose count in that minute..

Road Fan

Just count for 5 seconds and then multiply by 12. Clearly accuracy does not matter too much.

If the underlying purpose is for training, probably it's cheaper to teach the community to estimate RPE.