There are very many ways to skin this cat, but I like to do this: Choose one ring, whether it be the outer or the middle in a triple, or the outer on a double, on which I can do most of my riding, including downhills and tailwinds, and most hills and headwinds. I do this by changing my cassette as needed. I first choose the lowest high and the highest low that are convenient, and then try to get the desired cruising gears in the middle of the cluster. Me, I like 5 or so very closely spaced gears in the (for road) 60" to 80" range; a 50" and a 40" are nice on the low end, and an 85" or so is nice for a high. I won't spurn a 90" or even 100" high, but such gears are very low down on my list of wants.
If I use a wide range double, I'd choose the cogs to give me this sort of spread on the outer ring. If I were using a triple, I'd go slightly higher at both high and low end -- that 90 or 95 or 100" high and a 50" low, say, with the middle chosen more as a separate intermediate range -- say from mid 70s to 30s -- instead of being set up for sequential shifting with the big ring. With the Matthews, I run a 44 outer for pavement -- 84" down to 48", a 40 for dirt -- 76" down to 38"; and the granny down to 25". I don't intend shifting sequentially between the 44 and the 40; they are separate ranges for different conditions. Frankly, I'd choose a wide range double, except that the gearing I prefer is easier to get on my particular crankset (standard external bearing Bontrager mtb crank) with a triple than with a double (ie, they don't make 39 t and 25 t rings for the 104/64 type of crank). Then I choose a granny or inner that gives me the lowest gear I even theoretically might use on this bike -- the criterion for this being the type of riding I expect to use the bike for. A road bike won't get the same gearing as a bike meant for steep off road climbs. For me, a 25" low would be gravy and icing and gilding all in one, and the 26X30 low on the Matthews gives me just that. Regarding derailleurs: probably not; unless you swap in cogs that are much bigger than you are using now, there would be no point. You might have to shorten the chain. Heck, I didn't even lower the LX fd after I tossed the original 46 outer and installed a 38 in the middle position to use as the big ring; it shifted fine. Why do you want to switch to a double? Do you have a concrete goal in mind, or is this just an experiment? If the latter, then try it out. I've tried just about every combination using cassettes with up to 9 cogs, and it is based on trying all of these, and discovering what I don't like, that allows me to know what I do like. Here is the 38/24 double I used on the Fargo -- note, 28.5" wheels. What I sort of slightly dislike is the 68" and 64" cruising gears; I prefer the 70"-66"-60" series that the 44 gives me. As you might guess, it's really not that big a deal, but I do prefer slightly higher gearing with the 175 mm Bontrager. 38.0 24.0 13.0 83.3 14.0 77.4 48.9 15.0 72.2 45.6 16.0 67.7 42.8 17.0 63.7 40.2 18.0 60.2 38.0 20.0 54.2 34.2 23.0 47.1 29.7 27.0 40.1 25.3 Again, skin the cat in the way you prefer to do it. On Wed, Jun 1, 2016 at 9:42 PM, Lungimsam <john11.2...@gmail.com> wrote: > History: > I use a 26-36-46 up front right now > I use a 13-30 7-speed cassette in back (avoids autoshifts with friction > that way). > Bleriot. 135mm d'outs in the back. > This enables 95% of the hills I ride without dropping to the granny ring. > But sometimes I must use it. Happy to do so, too. > I ain't giving up friction shifting, and I ain't giving up 7-speed. So > don't even. > > > 1. I know if I go to compact double, a 24 chainring will be the inner > ring, so that is settled. In stone. Because of the climbs I sometimes > encounter. > > But it is selecting the outside ring that gets me. > > 2. The majority of hills where I ride I ride in the 36 x 30 combo. > Anything harder and I dump down to the granny. 26 x 30. > So there is no way I could ride a 40-something big ring. So I am confused > about how to select the best toothcount for me for my big ring so that I > don't alos spin out on the downhills, yet can do the uphills without the > granny dump. > > 3. Should I just use the ring that would enable me to cruise flats in the > middle of cassette? > 4. Should I also then change the cassette to the widest 7-speed possible? > > I once tried a racer geared compact double bike and it wasn't for me. No > low enough small ring and too big of a big ring resulted in lots of FD > shifting, which I am trying to avoid. > > > -- > 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-bunch+unsubscr...@googlegroups.com. > To post to this group, send email to rbw-owners-bunch@googlegroups.com. > Visit this group at https://groups.google.com/group/rbw-owners-bunch. > For more options, visit https://groups.google.com/d/optout. > -- Resumes, LinkedIn profiles, bios, and letters that get interviews. By-the-hour resume and LinkedIn coaching. Other professional writing services. http://www.resumespecialties.com/ www.linkedin.com/in/patrickmooreresumespec/ Patrick Moore Alburquerque, Nouvelle Mexique, Vereinigte Staaten ************************************************************************** ************** *The point which is the pivot of the norm is the motionless center of a circumference on the contours of which all conditions, distinctions, and individualities revolve. *Chuang Tzu *Stat crux dum volvitur orbis.* *(The cross stands motionless while the world revolves.) *Carthusian motto *It is *we *who change; *He* remains the same.* Eckhart *Kinei hos eromenon.* (*It moves [all things] as the beloved.) *Aristotle -- 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-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. 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