on 5/19/10 9:30 AM, William at tapebu...@gmail.com wrote: > Jim > > I think some of the compounding confusion comes from the Riv site. > There, they claim a 100mm dirt drop stem has an effective horizontal > extension of 82mm. I think that should simply read 'extension' with > 'horizontal' removed. That's what my 100mm dirt drop stem measures > to, and only then does the trig make any sense. Every vendor that > sells both the dirt drop and the Technomic call them +35deg and > -17deg, respectively. Take a glance at the dirt drop stem installed > on the bike and it is obvious that the rise on the bike is >>35 > degrees from horizontal. It's about 54 degrees (35 degrees in stem > rise plus the complement to the headtube angle which in this case is > 19 degrees). > > So, by my reckoning, the 100mm Dirt Drop stem does in fact have 82mm > of extension and ~86.5mm of reach. That I've measured > By that same approach, the 80mm Dirt Drop stem has 65mm of extension > and ~69.4mm of reach. That I have not measured > > Using that fact, it turns out that a 80mm dirt drop stem which has 35 > degrees of rise in the stem and ~65mm of extension, is within a mm or > two of a 7cm Technomic Deluxe in reach.
Thanks for that salient and comprehensive explanation. I certainly got it all mucked up interchanging "reach" and "extension". I appreciate the clarification. - J -- Jim Edgar cyclofi...@earthlink.net Cyclofiend Bicycle Photo Galleries - http://www.cyclofiend.com Current Classics - Cross Bikes Singlespeed - Working Bikes The Gallery needs your photos! Send 'em in - Here's how: http://www.cyclofiend.com/guidelines "She edged in to get a better look at the bike, how it was made, the intricacy of its brakes and shifters pulling her straight in. Beauty." -- William Gibson, "Virtual Light" -- 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=en.
