Used a CATEYE Velo 9, 08/11/2020

UPDATE 08/15/2020: Direct readout of cadence. Per a comment in this thread by jmshnsy, Sset wheel circumference to 166cm. Magnet(s) needed on only one spoke of the chainwheel. 8.6kph on the display equals 86 rpm. I found it easy to read on the Velo 9. Thank you jmshnsy!



Because of the high percentage of negative online reviews for the Schwinn computer, I decided to use a CATEYE Velo 9. The Velo 9 was $33 at Amazon. The Velo 7 ($30, slightly smaller display) also would have worked, but it was on backorder.



I used neodymium magnets. At $10 for a 10-pack (.315” Dia. x .118” Thk) at Home Depot, they’re more expensive than ceramic, but also MUCH stronger. My smallest chain ring is dished and has four spokes. To get the magnets closer to the sensor, I stacked two magnets on each spoke. In over 50 miles of riding, the magnets haven’t moved at all. I may secure them with silicone glue.



The maximum tire circumference that can be entered on the Velo 7 or the Velo 9 is 299cm (2990mm). The tire circumference numbers used to set up the Schwinn computer are too big to enter on the Velo computers. Per the original post, the number for four magnets is 4166mm. Half of 4166mm is 2083mm. For my four-magnet setup, I entered 208cm as the wheel circumference on my Velo 9. I have to double the displayed kmh number to get the actual cadence. Not a big deal for me.



UPDATE 08/15/2020: Direct readout of cadence. Per a comment here by jmshnsy, set wheel circumference to 166cm. Magnet(s) only needed on one spoke of the chainwheel. 8.6kph on the display equals 86 rpm. I found it easy to read on the Velo 9. Thank you jmshnsy!



Using a GPS speedometer app on my phone and the Sheldon Brown gear calculator (https://www.sheldonbrown.com/gear-calc.html), I checked theoretical mph vs. actual mph at multiple cadences and at multiple speeds. Actual mph was always within 0.5 mph of theoretical mph.



I’m an old, fat, out-of-shape guy (71, 5’9”, 230#) who has gained weight during the COVID-19 pandemic shutdown. Getting serious about riding the bike (My typical daily ride is 17miles at an average of 11 mph.) has gotten me back down to my pre-pandemic weight (218#).



Per the cadence meter, I pedal faster than I thought I did; a good thing. My “recreational” cadence is about 60. My “exercise” cadence is 76-86. My “too fast, shift to a higher gear” cadence is anything above 90.



I wanted a cadence meter that was cheaper than my bike. I wanted to avoid dealing with wireless. While my “CATEYE” solution is more expensive than the original poster’s “Schwinn” solution, I’m very happy with the results.



IMPORTANT NOTE: In the picture of the magnet packages, read the warnings on the packages of neodymium magnets. Not toys! Keep them away from kids!



My thanks to the original poster for coming up with the idea and doing the math!



