I am looking to change from a regular bike (I believe it's specefied as "DF") to a 'bent and I am not sure about the comments made regarding the speed going up-hill with a 'bent. Everybody seems to agree that the up-hill speed is slower. The question is:
a) slower, compared to somebody riding his DF standing up and putting all her/his weight into each stroke
b) slower, compared to somebody still sitting and using the leg muscels primarely.
From a mechanical point of view, I would give the advantage to the 'bent, if compared to a sitting rider on a DF. Anybody like to comment?
You can exert tremendous force on the pedals of a 'bent when you push back against the seat. This causes trauma to the knees and you can blow one. On a DF you are somewhat limited to your own body weight although I could develop a fair amount of power by pulling up on one pedal while putting my weight on the other and pulling up on the bars at the same time. Still not endangering my knees. On a 'bent you gear down and spin, applying power for nearly a full 360 degree crank revolution. Fast pedal RPMs in a low gear, kind of like granny gear on a mountain bike. The pedalling is easy (at least on my 'bent) but the speed is slow. I would say that I could climb a hill faster on my road bike but going up the same hill, albeit slower, is easier on my 'bent.
My experience in slightly hilly central Alabama where hill climbs are usually less than
700' and 2mi in length, is that on the same route, solo, I will average 1.5mph slower
on the bent compared with the DF for the ride, and 2-3mph slower on significant hills. A significant hill is one that knocks me under 7-8mph. I rarely stand on the DF for more than 5-10 pedal revolutions. My preferred technique on hills I can charge is to charge at 18-24mph and push hard to keep speed up. As speed drops to 15mph I downshift 3-4 gears and spin like crazy (for me 90rpm) til speed is down to 10-12mph and repeat 3gears lower. This works for say upto 50-80' rise in less than 250-300yds. By then I am either anaerobic or such that 6-8mph is where I am stuck til the hill ends. On shorter hills I can stay with the faster (18-22mph) tourers this
My bent seems more efficient than my DF on most hills. In my opinion, the circular application of power on the pedal stroke seems to distribute load to all leg-muscle goups more evenly -- I don't get tired as fast, so it's better for long rides. Generally, I climb faster on my bent on all but the steepest hills.
A low BB and tight hip-angle should also improve climbing. I have a European 26/20 SWB with HP-Velotechnik seat and it climbs best when the seat is most upright. My winter project is to extend the seat-bottom so the angle can be increased even more.