tag:blogger.com,1999:blog-1564958057737541664.post760358694767513904..comments2024-02-14T17:11:22.168-08:00Comments on On Bicycles, and.... what else is there?: Kyle and Berto's drivetrain efficiency datadjconnelhttp://www.blogger.com/profile/01484858820878605035noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-1564958057737541664.post-13313593083274329852016-02-18T13:51:59.374-08:002016-02-18T13:51:59.374-08:00Thanks for the comment! A lot of this earlier wo...Thanks for the comment! A lot of this earlier work has been eclipsed by FrictionFacts, who have done the best publicly available measurements. Cross-chaining is a relatively small penalty until you are fully crossed, or adjacent to fully crossed. In general... lower chain speed is more efficient, less chain bending is more efficient, and less chain tension is more efficient: loss comes from bending a chain under resistance so less bending, less resistance, or bending less often all reduce losses. I recommend checking out FrictionFacts.com for their reports, which are truly excellent.djconnelhttps://www.blogger.com/profile/01484858820878605035noreply@blogger.comtag:blogger.com,1999:blog-1564958057737541664.post-30200353038163474932016-01-21T09:45:24.141-08:002016-01-21T09:45:24.141-08:00I hit upon this post just today. It is now 6 years...I hit upon this post just today. It is now 6 years old and the efficiency issues have probably been advanced further. However, for other internet browsers searching on this topic, I want to point out that the efficiency data from Kyle and Berto are odd and suspect. <br /><br />Look at their Figure 11 plotting the effiency versus the gear number of the Shimano Ultegra 27-speed transmission. The data points lying below the dotted trendline are from left to right: 32/34 - 32/26 - 32/20 - 22/16 - 32/16 - 32/12). Remarkably, all combinations with the 32-chainring have a below-average efficiency. Oddly, gear 22/16 has a higher efficiency (93%) than gear 32/16 (92.5%), although the chain line is more cross. Even more odd, gear 22/12 has a much higher efficiency (91.5%) than gear 32/12 (89.5%) although the chain line is more cross. I believe this is enough reason to dispute the quality of these data. Nomathhttps://www.blogger.com/profile/07918887659342199131noreply@blogger.comtag:blogger.com,1999:blog-1564958057737541664.post-15752469658397806792010-01-15T15:07:17.461-08:002010-01-15T15:07:17.461-08:00I wasn't sure, actually, but apparently it is....I wasn't sure, actually, but apparently <a href="http://www.urbandictionary.com/define.php?term=stumpified" rel="nofollow">it is</a>.djconnelhttps://www.blogger.com/profile/01484858820878605035noreply@blogger.comtag:blogger.com,1999:blog-1564958057737541664.post-72796816036309470462010-01-15T11:03:00.350-08:002010-01-15T11:03:00.350-08:00is stumpified a word :)is stumpified a word :)NadiaMachttps://www.blogger.com/profile/02968728947175573760noreply@blogger.com