Hi Randy. I'm a Brit just getting into building bents (onto my 3rd prototype now) and have been disappointed at how little power I seem to be able to put down and how poorly (ie slowly) they climb compared to my road bike. I'm experimenting with body-hip angles and note that you have two quite different approaches between your trike and bike; the trike is EXTREMELY laid back (= very open body-hip angle) while the bike has a very upright rider position AND high BB (= very closed body-hip). Can you tell me which works best (for you) and why?
I notice that you have contributed sensible observations to other threads on this subject elsewhere, and you seem to favour blood oxygen/lactic acid arguments for rider position effects on performance. I intuitively feel that - for me at least - it's more a case of biomechanics, with a reclined posture not engaging the more powerful thigh and buttock muscles. This is mainly because my lack of power doesn't seem to come from fatigue/lactic acid build up, but merely from an inability to apply more pedal force. Also because I feel more (uncomfortable) strain around the knee joint rather than the normal (enjoyable) muscle strain in the thighs when pushing hard on an upright. Do you have any views on this biomechanic perspective?
Many thanks. Nick PS Both trike and bike are very impressive. Respect!
you're right, the laidback position is inferior to the closed position in every way from a power production standpoint. The only reason I use it is for aerodynamic gain (for flat time trials only). The closed position does activate more muscle tissue by stretching the glutes and hamstrings to a higher degree. And, as you have noted, it spares the weak link in the chain, the knees. This is best illustrated when taking off from a standing start. The difference in power is like night and day.
I answered a few days ago but somehow it disappeared. My now short answer is that the closed position is superior for power development. I only use the open position for aerodynamic gain and I do lose power doing so.
Thanks for your answers. Some time ago I tried out a dual seat position idea, but even the steeper seat angle didn't close the body angle enough. I've just done a back-to-back road test comparison on a 8km, 7% climb with (a) reclined, and (b) pulling up on the bars into a sitting position, and the latter is just better all round for speed and power on the climb. Interestingly the benefits of sitting up can remain for a minute or so when returning to reclined. Perhaps due to resting certain muscles?
Thanks for your comments and good luck with all your future projects.
4 comments:
Hi Randy.
I'm a Brit just getting into building bents (onto my 3rd prototype now) and have been disappointed at how little power I seem to be able to put down and how poorly (ie slowly) they climb compared to my road bike. I'm experimenting with body-hip angles and note that you have two quite different approaches between your trike and bike; the trike is EXTREMELY laid back (= very open body-hip angle) while the bike has a very upright rider position AND high BB (= very closed body-hip). Can you tell me which works best (for you) and why?
I notice that you have contributed sensible observations to other threads on this subject elsewhere, and you seem to favour blood oxygen/lactic acid arguments for rider position effects on performance. I intuitively feel that - for me at least - it's more a case of biomechanics, with a reclined posture not engaging the more powerful thigh and buttock muscles. This is mainly because my lack of power doesn't seem to come from fatigue/lactic acid build up, but merely from an inability to apply more pedal force. Also because I feel more (uncomfortable) strain around the knee joint rather than the normal (enjoyable) muscle strain in the thighs when pushing hard on an upright. Do you have any views on this biomechanic perspective?
Many thanks. Nick
PS Both trike and bike are very impressive. Respect!
Hi Nick,
you're right, the laidback position is inferior to the closed position in every way from a power production standpoint. The only reason I use it is for aerodynamic gain (for flat time trials only). The closed position does activate more muscle tissue by stretching the glutes and hamstrings to a higher degree. And, as you have noted, it spares the weak link in the chain, the knees. This is best illustrated when taking off from a standing start. The difference in power is like night and day.
Good luck in your bike and fitness building.
Nick,
I answered a few days ago but somehow it disappeared. My now short answer is that the closed position is superior for power development. I only use the open position for aerodynamic gain and I do lose power doing so.
Hi Randy
Thanks for your answers. Some time ago I tried out a dual seat position idea, but even the steeper seat angle didn't close the body angle enough. I've just done a back-to-back road test comparison on a 8km, 7% climb with (a) reclined, and (b) pulling up on the bars into a sitting position, and the latter is just better all round for speed and power on the climb. Interestingly the benefits of sitting up can remain for a minute or so when returning to reclined. Perhaps due to resting certain muscles?
Thanks for your comments and good luck with all your future projects.
Nick
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