It is difficult to do the geometric calculations which compare the Technomic to the Dirt Drop because it is hard to find a right triangle in the setup. It is fair to say that a 6 or 7cm Technomic will get you as close as you will get to the same position as an 80mm Dirt Drop -- within 5mm or so as Cyclofiend stated. However, with smaller frames, the Dirt Drop will bottom out in the steerer and you'll never the the Dirt Drop as low as the Technomic or Techno Deluxe.
On May 19, 9:01 am, CycloFiend <cyclofi...@earthlink.net> wrote: > on 5/18/10 11:36 PM, CycloFiend at cyclofi...@earthlink.net wrote: > > > > > > > on 5/18/10 9:57 PM, happyriding at happyrid...@yahoo.com wrote: > > >> On May 18, 8:38 pm, CycloFiend <cyclofi...@earthlink.net> wrote: > > >>> I'm not quite following your math (geometry?) on this. When they describe > >>> the horizontal extension as 65 mm, wouldn't that be the just 5 mm longer > >>> than a 6 cm Technomic stem? > > >> If you have two stems: an 80mm Dirt Drop (with 65mm extension) and a > >> 6cm Technomic, it will be impossible for you to get the bars in the > >> same spot--no matter what you do. Additionally, you will never get > >> the bars to be within even .5 cm of each other. > > > That's the statement I'm not following. > > > If the extension is 6.5 cm on the Dirt Drop stem, and the extension is 6 cm > > on the Technomic, the former will be .5 cm closer with the bars at the same > > height. > > > The extension is the measurement from the bolt center, which is the same as > > the center of the headtube. Whether you get there with an up-angle stem such > > as the DD or the "7" style of the Technomic doesn't matter. > > Now, y'see, I shouldn't be making late posts when fighting a head cold... > > It finally occurred to me why the 6 cm "7" style stem doesn't have a 6 cm > extension for the purposes of this comparison. Now, it did take me putting > pencil dots on the 12 cm Technomic I'm not using and measuring, but, hey, > sometimes I'm a visual learner... > > I was definitely confusing the idea of "Reach" and "Extension". > > Made me dig through my ref's and refind this link: > > http://www.habcycles.com/fitting.html > > and I'll work through this when my brain is better.. > > http://mathforum.org/library/drmath/view/53925.html > > oh, and though this is set up more for threadless (i.e. spacers) here's a > stem calculator (allows comparison for two sizes) - > > http://www.brightspoke.com/t/bike-stem-calculator.html? > > - Jim "...bed!" > > -- > Jim Edgar > cyclofi...@earthlink.net > > Current Classics Bicycle Photo Gallery -http://www.cyclofiend.com/cc > Cross Bike Photo Gallery -http://www.cyclofiend.com/cx > Single Speed Garage Photo Gallery -http://www.cyclofiend.com/ssg > Working Bikes & Practical Hardware -http://www.cyclofiend.com/working > Work Shops of the iBob's -http://www.cyclofiend.com/shop > > Gallery updates now appear here -http://cyclofiend.blogspot.com > > Send In Your Photos! - Here's how:http://www.cyclofiend.com/guidelines > > "That which is overdesigned, too highly specific, anticipates outcome; the > anticipation of outcome guarantees, if not failure, the absence of grace." > > William Gibson - "All Tomorrow's Parties" > > -- > 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 > athttp://groups.google.com/group/rbw-owners-bunch?hl=en.- Hide quoted text - > > - Show quoted text - -- 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.
