4 ms·

It's my understanding that the pros don't use this. If you don't have enough torque, you're probably doing it wrong, and would soon be out of gas even with mor

by adamtj 16y ago

It's my understanding that the pros don't use this. If you don't have enough torque, you're probably doing it wrong, and would soon be out of gas even with more mechanical advantage. Shift down, pedal faster.

oconnore 16y ago
This makes no sense. If you can generate the same power with less physical exertion, and no significant reduction in reliability or weight, why not take it?
- arethuza 16y ago
  I've seen comments about gear changing being slightly worse (which doesn't surprise me) and being overshadowed by things like moving from clips to SPD pedals.
- adamtj 16y ago
  Physical exertion equals power. You can't have the same power with less physical exertion. It's a trade-off between aerobic capacity and anaerobic capacity. You can pedal in a high gear, using more strength, or you can pedal faster in a lower gear, maintaining the same speed, but using more cardiovascular capacity. In both situations, if you are going the same speed, you are putting out the same amount of power. Non-circular gears change the gear ratio as you pedal. It effectively shifts down in that part of the pedal stroke where you have the least strength. Since the bike doesn't slow down, your feet must speed up. Then, when your feet swing around to where you have more strength, it effectively shifts up. My argument is, if you are pedaling at the limit of your strength, you are in too high a gear. Shift down and spin your feet faster. You'll use less strength, and more aerobic capacity, enabling you to maintain an equivalently high power output, but for longer. It's easier to run a marathon at a constant speed than to sprint 100 m at a time, taking walking breaks to maintain the same average speed.
  - eru 16y ago
    Isn't your analogy in the last paragraph a good argument in favour of non-circular gears? Gears that allow you to output the same amount of power all the time.
schultzor 16y ago
Oval chainrings (like Biopace, Rotor Q-Rings, etc.) are used by some pro cyclists. The oft-touted advantage for the system is the elimination of the "dead spot" at the top of the pedal stroke, but it still seems to very much be a case of personal preference. Just like there are some pros that prefer to spin an easier gear up a climb, while some would rather mash it out in the big ring. It all comes down to how good the motor (legs+lungs) is.

by adamtj 16y ago

oconnore 16y ago

This makes no sense. If you can generate the same power with less physical exertion, and no significant reduction in reliability or weight, why not take it?

arethuza 16y ago
I've seen comments about gear changing being slightly worse (which doesn't surprise me) and being overshadowed by things like moving from clips to SPD pedals.
adamtj 16y ago
Physical exertion equals power. You can't have the same power with less physical exertion. It's a trade-off between aerobic capacity and anaerobic capacity. You can pedal in a high gear, using more strength, or you can pedal faster in a lower gear, maintaining the same speed, but using more cardiovascular capacity. In both situations, if you are going the same speed, you are putting out the same amount of power. Non-circular gears change the gear ratio as you pedal. It effectively shifts down in that part of the pedal stroke where you have the least strength. Since the bike doesn't slow down, your feet must speed up. Then, when your feet swing around to where you have more strength, it effectively shifts up. My argument is, if you are pedaling at the limit of your strength, you are in too high a gear. Shift down and spin your feet faster. You'll use less strength, and more aerobic capacity, enabling you to maintain an equivalently high power output, but for longer. It's easier to run a marathon at a constant speed than to sprint 100 m at a time, taking walking breaks to maintain the same average speed.
- eru 16y ago
  Isn't your analogy in the last paragraph a good argument in favour of non-circular gears? Gears that allow you to output the same amount of power all the time.

schultzor 16y ago

Oval chainrings (like Biopace, Rotor Q-Rings, etc.) are used by some pro cyclists. The oft-touted advantage for the system is the elimination of the "dead spot" at the top of the pedal stroke, but it still seems to very much be a case of personal preference. Just like there are some pros that prefer to spin an easier gear up a climb, while some would rather mash it out in the big ring. It all comes down to how good the motor (legs+lungs) is.