With carbon fiber, all the old standards are thrown out! James Valiensi, PE Northridge, CA H818.775.1847 M.818.585.1796
On May 7, 2011, at 7:01 AM, Bill M. wrote: > I suspect that the introduction of carbon fiber bars had something to > do with the introduction of 31.8 mm bars as well. > > Bill > > > On May 6, 10:15 pm, James Valiensi <valie...@mac.com> wrote: >> Hey, >> My back of the envelope calc's indicate a standard aluminum quill stem will >> deflect about ten times more than a steel stem. This is with equal >> extensions lengths and loads, and the aluminum stem has a solid 22.2mm >> diameter extension, and the steel stem is 31.8mm OD w/ 25.4mm ID extension. >> The extension into the fork vs. clamping on the outside of the fork are not >> significant here. >> By the way, neither stem deflects that much. >> If you really want a stiff stem, use a short extension, and big diameter. >> And steel too. >> And you know why they went to 31.8mm diameter handle bars? Because of the >> stinking cable grooves. The grooves make the bar section too flexible, the >> bigger diameter overcame this. >> Cheers! >> James Valiensi, PE >> Northridge, CA >> H818.775.1847 M.818.585.1796 >> >> On May 6, 2011, at 6:44 PM, Philip Williamson wrote: >> >> >> >>> When I got my Quickbeam, I tried a couple of stems, including the >>> stock Technomic Deluxe and the Nitto Dirt Drop. Both flexed noticeably >>> more than the Salsa welded stem I ended up with. The Dirt Drop not as >>> much as the Technomic Deluxe, but the quill was bottomed out in the >>> steerer. >> >>> Philip >> >>> On May 6, 9:24 am, "Bill M." <bmenn...@comcast.net> wrote: >>>> Back in 1991 I bought a Cannondale (very stiff frame) that came with a >>>> standard quill stem. I swapped it out for a hollow, welded stem that >>>> had a much larger diameter extension. The first time I stood up and >>>> cranked the bike up a short steep rise I was astonished at how much >>>> stiffer the front end of the bike felt. The quill stem was allowing >>>> the bars to twist, the new one wasn't. >> >>>> That may or may not be seen as a good thing, but I have no doubt that >>>> typical threadless stems are stiffer in torsion than traditional quill >>>> stems. >> >>>> Bill >> >>>> On May 6, 3:58 am, MichaelH <mhech...@gmail.com> wrote: >> >>>>> The new RR contains an article by GP outlining his believes about >>>>> various aspects of bike strength, comfort, weight, and comfort. >>>>> There wasn't much new there for anyone who has followed him for a few >>>>> years, including why he prefers threaded headsets and stems, but it >>>>> did trigger this question from me. >> >>>>> My son, who is 39 years old and a very muscular 170 lbs claims that >>>>> he experiences stem flex while climbing with a traditional quill >>>>> stem. I am always disinclined to challenge people's subjective >>>>> experience but I have never experienced this and suspect it is in his >>>>> imagination. >> >>>>> Has anyone here felt their stem flex and has anyone ever broken a >>>>> stem? >> >>>>> michael >> >>> -- >>> 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-bunch@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. > > -- > 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-bunch@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. > -- 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-bunch@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.
