Originally Posted by
Richard Cranium
Yes, of course RPM is constant. But like some one mentioned - it is important that you give the magnet enough time to "pull" the sensing switch in the pickup unit.
Believe it or not, when i used to get fierce while riding rollers, i could get pickup sending units to "fail" or skip when riding at speeds near 50 mph. This was mostly because the unit was simply nearing being worn out. But it is proof that there was actual "mechanical" activity in older cat-eye and avocet units.
............
Kinda, sorta, maybe!
It's a hypothesis, and a very reasonable one. Another might be that the wheel under such loads it experiences at that speed deflects and deforms more at the outer diameters. So maybe not so much the time of engagement between the magnetic flux and the reed switches, but maybe more that the magnet for that revolution was further away from the sensor.
But who knows. I'm not going to go out and test it. But likely there are other possible reasons too.