Bill, Your math and plan seem spot on! FWIW the dos eno freewheels come in a 2 tooth difference. 16/18, 17/19, or 20/22. If you have a secret vender for a 16/19 (or greater) let me know. I would buy one in a heartbeat.
I have recently gotten back into single speed riding and on my Trek I have a 42x20 freewheel. I had plans to use a two speed fixed gear setup but ended up with a white industries wheelset. They make two speed freewheels but need proprietary fixed gear cogs. My freewheel set up with 57" gearing works well for me here in the san francisco hills. My two speed plan were to use a 17/21 Surly Dingle cog and a 38x34 110 crankset. Which would yield a high gear of 60" and a low of 44". The 60" gear would be my all around gear and the low gear would just be used as a knee saver for long and steep climbs or a slow gear for dirt paths. To me the 4t total difference from the dos eno freewheels is good for terrain changes (roads to offroad for example) but don't offer the same sort of flat ground to steep hill change you may be looking for. Single speeds are so sweet though, once you find a gear that works you don't miss the other ones. Jason sf,ca > On Mar 12, 2014, at 12:10 PM, Bill Lindsay <[email protected]> wrote: > > I have a build concept for a SimpleBeam kind of thing. The steep hill I live > on completely rules out a singlespeed for the uphill part, and rules out > riding fixed for the downhill part. Still, I notice that for my commute I > use a particular small handful of gears. It makes me think that it is > plausible for me to build a 2-speed, using a White 16/19 on the back and two > chainrings on the front with 3-teeth of difference, so I could have one rear > wheel position. > > Right now my concept is a 35/38 in front with the 16/19 in back. My two > gears: 35x19 and 38x16 would be 50" and 64" with 27" diameter wheels (700x32). > On a 110mm BCD, I could alternatively easily run a 36/39, a 39/42, a 40/43 or > a 42/45 in front without having to chase down any weird chainrings. > On a 94mm BCD, I could run a 29/32 for offroady stuff. > > As a shifting maneuver, I'd loosen the right side bolt. Stick-shift the > chain from big-to-small and then from small-to-big. Then tighten the right > side bolt again and ride away. > > Anyway, by my numbers, spinning at 110RPM with a 27" diameter wheel is 21mph, > which is plenty fast for road cruising for me, especially when I can coast > downhills. I think I can handle the 50" gear up my hill as well. > > I wonder what others feel they need. I know Patrick Moore zens out with a > slow metronome cadence climbing with 70-something gear inches. Who else > thinks my two speeds are a bad idea? > > Bill Lindsay > > -- > 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/d/optout. -- 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/d/optout.
