On Nov 19, 2009, at 11:24 AM, Steve Palincsar wrote: > On Thu, 2009-11-19 at 07:26 -0800, Jim Thill - Hiawatha Cyclery wrote: >> Mechanical inefficiency of the drivetrain is not the only thing that >> makes a cyclist slower. Let's say, for example, that 90% of the total >> inefficiency comes from tire rolling resistance and aerodynamics, and >> 10% comes from the mechanical friction and slop in the drivetrain. >> Then the total effect of a 6% drop in mechanical efficiency would >> translate to something like 10% of a 6% drop in speed (i.e. 0.6%). >> Approximately. My numbers are for illustrative purposes only, not >> based on actual measurements of inefficiency. > > > But I think the big issue with IG hubs isn't the actual > inefficiency -- > it's well known that 11T and 12T sprockets are extremely inefficient, > yet nobody complains about their inefficiency vs larger ones -- > it's the > feel, that slushy, squishy feeling that you're putting power in but it > isn't coming out. A derailleur drive train in any gear feels "solid" > under your pedal as you apply power, but 1st gear in a Sturmey AW (and > that is, after all, what most people have in their experience bank > when > you speak of internal geared hubs) doesn't.
That's not my experience with AWs and Sachs 3 speed hubs. YMMV. > Also the gear change in a derailleur system, even non-indexed, once it > stops clacking, feels "positive" compared to the gear change on an AW, > which somehow does not. > > People call that "inefficiency," even though nobody's measuring > power in > vs power out. It's that "friction box" feeling. Hmm. Maybe my hubs have been in fortunately good shape. My current IGH, a Sram T3, seems about as efficient as my derailleur setups by feel. The main problem is the overly large jumps between gears. -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to rbw-owners-bu...@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=.
