Originally Posted by
North Coast Joe
Andy (or other veterans), can you translate this for a total noob? The only way I could see that all the gears were working when the bike was inverted was to make one crank rotation and count the number of wheel rotations that occurred. I had to manually pull/release the shift chain because (I guess) the shift cable was so out of adjustment. Kinda surprized that there was only a 1/2 to 3/4 of a full rotation difference in wheel rotations between gears, but I've got to redo this test again, paying more attention.
Thanks again!
What i was referencing is that the cog and shell will rotate at different RPMs when in 1st or 3rd gears (second gear is typicially a direct through, 1:1 ratio. Which BTW is the most efficient gear to pedal in friction wise). If you shift into 1st gear (and the shifting adjustment is proper) the cog will rotate faster then the wheel will. So you watch the cog/chain and the spokes and see how they rotate in relation to each. As you pedal the cog will be moving past the spokes. When in 2nd gear the cog and spokes are rotating at the same pace so they will stay in phase. When in 3rd gear the spokew will travel faster then the cog and will pass them.
I use this to check hub function when servicing a bike or when estimating one for service. I also use this cog/spoke rotation to fine tune the cable tension adjustment. When in 2nd gear, you can run in and out the cable adjuster and see where the point of shift happens by watching the cog/spoke relationship. This way you end up establishing the "ends" of 2nd gear adjustment and I'll then adjust the cable in the center of this range. Andy.