Correct 36"er computer settings

I know I’m on a thread creating spree lately, but a thought just crossed my mind. Instead of using the high 2700 to low 2800 number in my wireless cycling computer for my 36 inch wheel, would it work to use three magnets instead? Two magnets would be okay but not evenly spaced out since there are only 9 pair of spokes per side so 3 magnets would mean that they would be evenly spaced. Even if this does work, what would the value of the “new wheel” need to be to get accurate measurements? I don’t think that dividing the ~2800 figure of the 36er wheel in 3 will work…any geometry majors around?

this should work, just devide your current rollout number by 3

it takes a wheel of 1/3 the diameter of another wheel exactly 3 turns for equal distance traveled.

it is an inverse relationship

the computer thinks you are spinning 3X as fast on a wheel 1/3 the size:



Dividing the total rollout by three will work for three equally spaced magnets.

Dividing the rollout by two will also work for two magnets. As long as the magnets are on spokes on opposite holes. Because one spoke will be ‘leading’ and the other ‘trailing’ then they will be a few milimeters off of the center line, although the closer to the rim you are, the more accurate they’ll be. But in terms of distance ridden, it’ll still work out spot on. In terms of speed, it’ll fluctuate so slightly that unless you’re looking at it to one 100th of a mph, then I’m sure you’ll never notice.