dirk.bonne@xxxxxxx Sendt af: python-bounce@xxxxxxxxxxxxx 24-01-2007 14:14 Besvar venligst til python@xxxxxxxxxxxxx Til python@xxxxxxxxxxxxx cc Emne [python] Re: another newcomer Henry Thomas wrote: dirk.bonne@xxxxxxx wrote: FYI: there has been documented measurements related to this. Check out this pdf: http://www.ligfiets.net/redactie/meetligfietsengels.pdf Dirk Dirk, thanks for sharing this with us, it was a very interesting read. There isn't a lot of test data like this that I have found which is specifically dealing with recumbent. I am a bit confused about the tires. As I read it, larger rims (26") and firmer rubber compounds are better at higher pressures (110psi). However I thought that the Specialized Fat Boy was softer than the Schwalbe Stelvio Kevlar, or is that not the case. I read the opposite out of this paragraph and thus no contradiction. The supple rubber compounds are better. The stelvio material is stiffer and also has a worse performance. What I think is interesting is that extreme height differences between seat / BB are not needed. From 15 -> 25cm is no much different in power. So you can just as well use 15cms (more ergonomic). note, the measurement was made for seat angle of 21degrees. Dirk Well, I don't remember exactly where, but I read that given the SAME air pressure, a wider tire will deform less, as the weight is distributed over a larger area contact patch. The rubber itself does not account for much rolling resistance. However, usually the large rims are used with less pressure to obtain a smoother ride, better shock absorption or better grip for off-road uses. Rasmus Møller