Michael wrote A difference of 10 between rings consistently yields a single step on the cogs, and a difference of 14 yields 2 clicks, but a difference of 12 is neither one nor the other.
It seems to me that this depends on the gears in the rear cassette. For example, for a Harris Cyclery 9 speed century special 13-14-15-17-19-21-24-27-30 cassette, the changing from a 36 to 46 ring equals 2 steps on the rear cogs for cogs 15 and up. In general, these gearing choices are really a personal preference. What really matters is what you are trying to achieve. It seems to me Michael likes the fact that the big ring in cog n provides roughly the same gear as the small ring in cog n+2. I think what this means is that he likes that in the high gears of the small ring or the lower gears of the big ring provide him the gears he likes without needing a front shift. On the other hand, this means that the big ring and small ring duplicate several gears. Another's preference might be to choose the rings and rear cassette to provide as many unique gears as possible. As I understand it, this is the idea of a half step (say 52-47) front ring. Jumping down to the small ring gives you a gear halfway between gears on the big ring. However, you get that uniqueness only by making a lot of FD shifts. (Note a BQ article last year points out how electronic shifting could make this convenient in the future.) Lately, I've concluded my own personal preference is to use a triple so that I can use narrower range in the rear cassette, and get closer gear ratios with RD gear changes. But that's just feels good to me. Preferences will vary depending on how you pedal and on what kind of hills you ride. ...Roy On Thu, Feb 11, 2010 at 9:50 AM, Frederick, Steve <frede...@mail.lib.msu.edu > wrote: > I've come to prefer a 10-tooth jump between chainrings but I didn't really > understand why they seemed best. Thanks much to Michael for 'splainin' it! > > Steve Frederick, East Lansing, MI > > -----Original Message----- > From: rbw-owners-bunch@googlegroups.com > [mailto:rbw-owners-bu...@googlegroups.com]on Behalf Of doug peterson > Sent: Wednesday, February 10, 2010 11:42 PM > To: RBW Owners Bunch > Subject: [RBW] Re: Sugino XD cranks/chainring question > > > Here's a second to Michael's comments about 12 tooth difference vs 10 > or 14. I'll bet your triple has 46/36/26 or 24. I'd be inclined to > ride the 48/34 combo before changing things. Don't forget the other > end of the drive train when thinking about ring changes. A 13-30 or > 32 cluster would be nice with a compact double. A 48 x 12 high gear > is pretty racy & perish the thought of anything with an 11. > > dougP > > On Feb 10, 6:28 pm, MichaelH <mhech...@gmail.com> wrote: > > Why 46/34 rather than 48/34? If you lay out the ratios in a chart, > > you will quickly se that the 48/34 has more consistent jumps between > > gears with a simpler shifting pattern. If you don't know how to lay > > this out, I can help you. A difference of 10 between rings > > consistently yields a single step on the cogs, and a difference of 14 > > yields 2 clicks, but a difference of 12 is neither one nor the other. > > > > Personally, I find the ramps on chain rings way over rated. These > > shifting aids have real value add on cogs, but I haven't experienced > > enough benefit on rings to go out of my may to buy them. > > > > Michael > > > > On Feb 9, 9:22 pm, Mike <mjawn...@gmail.com> wrote: > > > > > > > > > I'm in the process of changing out cranks on my Hilsen. I'll be > > > switching from a Sugino triple to a Sugino compact double. The double > > > has 48/34 rings but I think what I want is 46/34. My Rambouillet has a > > > 46t chainring on it that I might cannabalize but I'm thinking of just > > > using the 46t ring off the triple. The 48t ring is clearly ramped and > > > pinned. The 46t ring on the triple does not look ramped at all. Is > > > that correct? It seemed to shift fine. I notice that the Sugino > > > chainrings that Riv uses have "no ramps or pins", are those the same > > > as the chainrings that come on the crank? > > > > > --mike- 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<rbw-owners-bunch%2bunsubscr...@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-bu...@googlegroups.com. > To unsubscribe from this group, send email to > rbw-owners-bunch+unsubscr...@googlegroups.com<rbw-owners-bunch%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/rbw-owners-bunch?hl=en. > > -- Roy D. Yates Professor, E&CE Associate Director, WINLAB http://www.winlab.rutgers.edu/~ryates -- 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.
