I've easily accommodated 17t and 22t cogs with a single 42t chainring on my QB. With the 42x17 the wheel was at the rearward extremity of the dropouts; with the 42x22 it wasn't all the way forward, so I could imagine I could have gone with a bigger difference.
Philip, I'm skeptical that two chainrings always gives better chainline with the Surly Dingle setup. If you look at it, the two cogs are extremely close together on a dingle (hence the need to use a narrower 9spd chain, to prevent the chain catching on the larger cog as it runs in the small one)...way less than the 5mm that is common between chainrings. Given how thick crank spiders are, and the thickness of chainrings, chainring clearance on any given frame, and the finite BB lengths (and thus chainline adjustments) commonly available, I think it's pretty hard to nail an ideal setup, which would still probably be a compromise in terms of chainline, with the chainrings straddling the proper chainlines for their respective cogs since it's pretty much impossible for them to bet that close together. In practice, I tried the two ring dingle setup for a while, played around BB length a bunch. I found that I could generally nail chainline in one of the gears, but the other gear would be way out. The better compromise for me, not caring as much about fender line and having super long dropouts (campy copies on my Salsa Casseroll), worked out to be a single chainring set at the track-standard 42mm chainline, pretty much splitting the difference between the two cogs (since my dingle was mounted on a standard (phil) track hub with 42mm chainline). That way the chainline was out at most 1 or 2mm in either direction, and both gears were equally smooth running. On Monday, November 25, 2013 10:46:43 PM UTC-8, Philip Williamson wrote: > > Two chainrings is way slicker. Better chainline in each gear, more gear > difference per rear tooth change, and two gears with a clean fender line in > each. The only reason I have a single ring on the Quickbeam is because I > put an older, prettier Shimano 600 crank on it, and it sits too close to > the frame for a second ring. > > The Ross has a 51" - 70" range, and the axle doesn't move at all. > http://www.biketinker.com/2012/fine-bikes/state-of-the-bikes-3-11-12/ > > Philip > www.biketinker.com > > On Monday, November 25, 2013 3:16:38 PM UTC-8, Patrick Moore wrote: >> >> That's the way to go, then -- thanks. I could use a 17/21 instead of the >> current 17/20, and have a 22 or so for a real bail out. >> >> I've thought of two rings, but frankly prefer the simplicity and hassle >> of accommodating 3+ teeth in the back. >> >> >> On Mon, Nov 25, 2013 at 2:18 PM, Philip Williamson <philip.w...@gmail.com >> > wrote: >> >>> I get an easy 4 teeth difference, and I'm pretty sure I could get 8. >>> Let's see - currently I have a 44t single ring, a 15t fixed cog, and a >>> Dingle 17-21, and they all work fine with 37mm tires. Significantly fatter >>> tires keeps the 44/21 from working. >>> >>> So: Six teeth for sure, with 37mm tires. >>> >>> Philip >>> www.biketinker.com<http://www.google.com/url?q=http%3A%2F%2Fwww.biketinker.com&sa=D&sntz=1&usg=AFQjCNHQ7rECiOZi3g57gDuuurKPduxuag> >>> >>> >>> On Monday, November 25, 2013 11:43:47 AM UTC-8, Patrick Moore wrote: >>> >>>> Thanks -- what about with a single ring: how many cogs can you get out >>>> of the QB/SO dropout when all is optimized? >>>> >>>> >>>> On Mon, Nov 25, 2013 at 11:16 AM, Cyclofiend Jim < >>>> cyclo...@earthlink.net> wrote: >>>> >>>>> Didn't realize the Dingle required a 9 sp chain. >>>>> >>>>> My stock gearing setup is the 40/32 front chainring setup with a 14T >>>>> fixed and 18T FW. The 40x14 (centered) and 40x18 fit easily. The 32x18 >>>>> is >>>>> at the end of the dropout with that chain length. >>>>> >>>>> Hope that helps, >>>>> >>>>> - Jim >>>>> >>>>> >>>>> On Monday, November 25, 2013 9:38:41 AM UTC-8, Patrick Moore wrote: >>>>> >>>>>> The Converted (Campy) Curt Custom ('03) has long 1010s, but given my >>>>>> peculiar choice of ring and cog, any ~70" cruising gear puts the axle in >>>>>> the middle of the dropout, but too close to the end to accommodate >>>>>> another >>>>>> full chain link. This means that the dropout cannot accommodate a larger >>>>>> cog that is 3 t bigger -- the axle is halfway out of the dropout with >>>>>> such >>>>>> a cog. >>>>>> >>>>>> A half link would work if I were not using a Dingle, which requires a >>>>>> 9 speed chain -- they don't make 9 speed chain half links (I asked Surly >>>>>> and half link makers). >>>>>> >>>>>> So, I am thinking of modifying, once again, the dropouts. Perhaps >>>>>> track ends? >>>>>> >>>>>> And this is the question: if optimally placed, how great a tooth >>>>>> difference can the track ends on the QB and SO accept? Or, are these >>>>>> track >>>>>> ends longer than Campy 1010s? >>>>>> >>>>>> Can a SO or QB accommodate a 4 t difference? >>>>>> >>>>>> Thanks. >>>>>> >>>>>> Patrick "no confusion, please, I've been quite clear" Moore >>>>>> >>>>>> -- >>>>>> *RESUMES THAT GET YOU NOTICED!* >>>>>> Certified Resume Writer >>>>>> http://resumespecialties.com/index.html<http://www.google.com/url?q=http%3A%2F%2Fresumespecialties.com%2Findex.html&sa=D&sntz=1&usg=AFQjCNGvfO7XcNjds72nVr2MRK3TzofP3g> >>>>>> patric...@resumespecialties.com >>>>>> http://www.linkedin.com/in/patrickmooreresumespec/<http://www.google.com/url?q=http%3A%2F%2Fwww.linkedin.com%2Fin%2Fpatrickmooreresumespec%2F&sa=D&sntz=1&usg=AFQjCNGDq66YE8o4yymSTf2GCgueeFKsYQ> >>>>>> >>>>>> 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 rbw-owners-bun...@googlegroups.com. >>>>> To post to this group, send email to rbw-owne...@googlegroups.com. >>>>> >>>>> Visit this group at http://groups.google.com/group/rbw-owners-bunch. >>>>> For more options, visit https://groups.google.com/groups/opt_out. >>>>> >>>> >>>> >>>> >>>> -- >>>> *RESUMES THAT GET YOU NOTICED!* >>>> Certified Resume Writer >>>> http://resumespecialties.com/index.html<http://www.google.com/url?q=http%3A%2F%2Fresumespecialties.com%2Findex.html&sa=D&sntz=1&usg=AFQjCNGvfO7XcNjds72nVr2MRK3TzofP3g> >>>> patric...@resumespecialties.com >>>> http://www.linkedin.com/in/patrickmooreresumespec/<http://www.google.com/url?q=http%3A%2F%2Fwww.linkedin.com%2Fin%2Fpatrickmooreresumespec%2F&sa=D&sntz=1&usg=AFQjCNGDq66YE8o4yymSTf2GCgueeFKsYQ> >>>> >>>> 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 rbw-owners-bun...@googlegroups.com. >>> To post to this group, send email to rbw-owne...@googlegroups.com. >>> Visit this group at http://groups.google.com/group/rbw-owners-bunch. >>> For more options, visit https://groups.google.com/groups/opt_out. >>> >> >> >> >> -- >> *RESUMES THAT GET YOU NOTICED!* >> Certified Resume Writer >> http://resumespecialties.com/index.html<http://www.google.com/url?q=http%3A%2F%2Fresumespecialties.com%2Findex.html&sa=D&sntz=1&usg=AFQjCNGvfO7XcNjds72nVr2MRK3TzofP3g> >> patric...@resumespecialties.com >> http://www.linkedin.com/in/patrickmooreresumespec/<http://www.google.com/url?q=http%3A%2F%2Fwww.linkedin.com%2Fin%2Fpatrickmooreresumespec%2F&sa=D&sntz=1&usg=AFQjCNGDq66YE8o4yymSTf2GCgueeFKsYQ> >> >> Albuquerque, NM >> > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. 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