Using Sheldon's gear calculator just now shows the chainring changes at about 26% and the cog changes averaging about 15% for my preferred combination of cogs.
But to specifically address my question, would a 13-14-16-19-22-26 be a good choice for a half-stepper? From what I using a gear chart, a 52/48 would work nicely with the cluster above, at least the five largest cogs. It sounds like this 13-26 might have started in someone's mind as a 14-26 five-speed that had a 13 stuck on to it.
And a related question - did racers half-step or only tourists?
-S-
Harvey M Sachs wrote:
>
> Steve -
> what I find most helpful is to plot these things on a gear chart, with the
> chainwheels as the columns and the freewheel cogs as the rows. the
> intersection cells get the gear, which I usually do as gear inches
> (=27*cw/fw). The 13-26 you have selected is a close as possible to
> geometrically equal steps (constant ratios). I think you will find that
> the 42/53 or 42/52 puts one chainwheel shift just larger than one freewheel
> shift.
>
> Us half-step guys would aim for a 4-tooth difference with that freewheel,
> so each chainring change splits the gap between two freewheels. (with your
> set-up, 8 on the chainring should be about the same as the step between two
> freewheel cogs). I haven't checked out the numbers, leaving that as an
> exercize for the reader, but pretty confident that's what you'll find.
>
> FWIW, I generally ride with a "half-step" as described above with 5- and
> 6-speed setups. For a 5-speed, here's the guide:
>
> 3 cw teeth splits a 14 - 24
> 4 cw teeth splits a 14 -28
>
> and so on.
>
> harvey sachs
> mclean va
>
> At 21:15 4/2/2001 -0400, Steve Freides wrote:
> >I would like to know if, during the 6-speed freewheel era, 13-26 was a
> >popular choice for a freewheel. Whether it was that or just close to that,
> >I'd like to know the specific cogs usually used.
> >
> >All my asking about chain for my Raleigh has reminded me that I have
> >mixed-breed Shimano freewheel on there now because that's how I could piece
> >together the combination I wanted, which is 13-15-17-20-23-26. I recall
> >hearing that using a 22 in the next to the last position was more common but
> >that seems like too big a jump to me. I'm pretty sure the freewheel body
> >I'm now using originally was configured as 13-14-16-19-22-26.
> >
> >If it matters, and I believe it does, I'm riding with a 42/53 in the front,
> >and I think 42/52 and 42/53 were both popular then.
> >
> >I confess that my inspiration for both cog and chainring choices comes from
> >my working out my preferences with modern 2x9 drivetrains, where I also ride
> >42/53 and 13-26, the latter as 13-17,19,21,23,26. I'll also note that 13-26
> >is neither a racer's nor a tourist's choice, but since I'm neither a racer
> >nor a tourist, I think that's OK.
> >
> >--
> >Steve Freides in ever more sunny Ridgewood, NJ.
> >
> >_______________________________________________
--
Steve Freides