I've bitched and moaned on this list about the annoying position of the retrofit Campy 1010s on the '03 Curt (installed by local builder Dave Porter some 6-7 years ago), that, with my preferred ring-and-cog combos, leave the axle at the 1/2 or even the 3/5 point along the dropouts in the cruising cog, so that I am limited to another 2 teeth before I run out of dropout room. Since I lika-da-Dingle, this has limited me to a 17/19 instead of the 17/20.
(Tho' I found after grudgingly installing the 17/19 that the 19/63" is the perfect chugging-along gear for extended hills and headwinds when I am carrying a heavy load.) I talked to other local builder Chauncey Matthews about re-positioning the dropouts, but he was reluctant to undertake the job, so after much fretting and internal anguish, today I took big and small rattails and a flat file to them and laboriously filed them back by a couple of mm. Lo and behold, a very little horizontal distance takes up a heckuvalotta chain slack. The axle is now within a mm of the back-end of the dropout in the 48/17, and there is ample room for, not only a 20, but, I daresay, even a 22 or 23. Not that my mighty quads need such piddling gears. I may have to file the dropouts back another mm or so to take up chain slack as the chain "stretches", but that should be no problem. The backend of the dropouts is noticeably thinner now, but there is ample metal to support the axle. I had to do the same thing to the '99 Joe gofast when I got it in '99, since I had -- thou fool! -- neglected to specify long dropouts and got Riv's then-current short horizontals. But the file did its work and the gofast can take a 5-tooth jump: I've installed a 20 t (or was it a 21?); the crusing 75" is a 46/15. All of this leading up to a couple of questions: 1. How much linear "stretch constitutes sufficient chain wear to require replacing the chain? (I use a Park tool, and I've found that, on the '99 Joe, when I just begin to notice that I cannot any longer take up sufficient slack, the tool measures close to 100% worn. So the dropouts make up a kind of on-bike chain check setup.) It can't be more than a very few mm. 2. Is it true, or is it false, that the lateral movement of the axle as you move it back and forth to accommodate smaller and bigger cogs, is 1/2 the distance that would be required if the chain were a mere single run, instead of being the double run it is? My head can't wrap around this one enough to picture the results of looping the chain versus a single line of chain. (That question makes sense to me, buddy.) 3. Is there a formula to convert linear axle movement to vertical chain deflection? That is: if I measure 1 3/4? of chain sag from the horizontal, then pull the axle back so that the chain is now horizontal (I know that this term is inexact), is there a formula that will tell me how much the axle will move laterally? (For Steve P.: Steve: it's *great* fun filing away energetically with crude hand tools at a $3,500 custom frame!) Patrick Moore, who would be at a total loss if he hadn't such trivial esoterica to fret about, in Burque, NM. -- *RESUMES THAT GET YOU NOTICED!* Certified Resume Writer http://resumespecialties.com/index.html [email protected] http://www.linkedin.com/in/patrickmooreresumespec/ Albuquerque, NM -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/groups/opt_out.
