1. Welcome to the esoteric and exotic world of fixed gear bike gearing. 2. Multiplicity in the rear is always better than multiplicity at the front. Hermeneutic: a. A single tooth's difference in the rear makes a much bigger gearing jump than a single tooth's difference in the front. b. It's much easier to swap the chain from a cog to an adjacent cog, while you are squatting behind the bike manipulating the QR or your box wrench with one hand, than to do this from one chainring to another.
3. You must strike a careful balance between doing what you can with what you have, and selecting the gearing that best suits you and your riding needs. Hermeneutic: a. Decide where the bike will most be ridden: Kansas or Boulder? Smooth pavement or 2" deep sand? Unladen or pulling a child trailer? b. Choose your gearing strategy. Hermeneutic: i. Do you stop and swap cogs at the slightest rise? Or do you hate stopping and prefer to grind up hills and against winds? ii. Do you prefer to twiddle on flats in order to have an easier gear for climbs? Do you have a freewheel for downhills? c. Taking this into account, choose a comfortable cruising gear, one suited for flat land speed and still winds. d. Choose a lower gear that will nicely serve when (i) you are feeling weak and the wind is strong; (ii) you have an exceptionally long hill that can't simply be walked (my cutoff for taking the trouble to swap cogs is about 1/2 mile. I can generally go at least 1/4 mile up even a 10%+ grade, and I don't mind walking 1/4 mile). Commentary: my own experience started with the worry about hills: I need a low gear to climb. So for road riding I started with a 63" gear. Too damned low; nothing more futile and exasperating than flailing away hopelessly on a flat with a tailwind in too low a gear. Easier to suffer a bit on the climbs. I moved to ~67-68", then to 70" for a bike that sees loads and that has fender flaps and bags to catch the wind; 75-76" for a gofast. These gears have served me well in rolling, windy terrain for 17+ years. I go down 2 teeth on the flip cogs -- 63" and 67" respectively -- for longer climbs and strong headwinds, or for lazy days. Note that as I approach Social Security Benefits age, I may gear down a tooth or so. I was younger -- ~ 48-50 -- but I found that a 67" gear was just right for pulling my then 2-4 year old daughter in a child trailer against headwinds -- given that headwinds inevitably turned into tailwinds. For off road, shorter (sub 20 mile) rides on rolling terrain with some very steep but short hills, and sandy soil, I tried a 60" fixed drivetrain, which was alright for flats, nice for hills (I still had to walk the steeper or more sandy ones), but I hated, just hated the low gear for flats and tailwinds, esp since this bike had 175s instead of 170s. There are few experiences more discouraging than flailing despairingly on the flat with a tailwind in a 60" gear with 175 mm cranks. I found that 170s with a 63" or 65" gear was much better; you walk a wee bit more but the rest is far more comfortable. If I were to ride SS or fixed again in such conditions, I'd have a 65" gear with perhaps a 55" low for long climbs in sandy conditions. A real off road bike is the one instance where I'd add a second chainring, and pair it with a large cog in back, to get a bigger gap between flatland cruising and technical stuff. Otherwise, I'd make do with a Dingle cog (IIRC, they come in 17/19 and 17/20) or a flipside cog. Again, it makes no sense to have 2 chainrings but only 1 cog. Note that the S3X hub is a possibility -- direct high with 75% 2nd and 62.5% 1st; though it has its own liabilities, notably the annoying lash. 4. A few mm either way won't mar the chainline enough to cause problems, especially if you are using a modern bushingless chain. Cogs and rings are easily available in 3/32 width. 5. The right QRs are fine for fixed/ss wheels; just choose an old fashioned, internal cam, all steel one. External cam QRs won't hold and can be used only with vertical dropouts. If a QR can be used successfully with a derailleur drivetrain in a horizontal dropout, it will work with a fixed gear or ss drivetrain. 6. Relates to #3 (b): your gearing strategy. Me, I think it's foolish to ride a ss or fixie and then try to switch gears for every rise in the road. You have to decide for yourself where the breaking point is, but my own approach is to select a gear that is best for an entire ride, or a section of a ride, and just leave it there until I'm done. For example, I've got a couple of routes there the outbound involves climbing, the return downhills. I put the bike in the bigger cog outbound, and when I turn around, I switch. Overall, and in all seriousness, fixed riding is really, really fun and, over the last 21 years, I've come to prefer it to riding multispeed; my only multispeed bike out of 4 is my dirt road bike, and even with that I often think of ss-ifying it. But if you're going to ride fixed, do it and get used to it; it involves a change not only of pedaling habits but of mindset -- and it's this last, really, that I find so attractive: you acquire the mental habit of doing more with less, which is pretty much the general definition of elegance. In particular, you learn to pace yourself for hills and winds; you learn to anticipate; you develop new techniques (the traditional idea of *habitus*, a more or less permanently acquired change in your soul and body or, if you don't understand those terms, your psychology and your physiology); and you find for example that you are quite sanguine about standing most of the way up a 5 mile climb. People on this list far more talented than I have done P-B-P on fixies and climbed the Rockies in amazingly huge fixed gears. It's a different style of riding, and you have to accept it for what it is and adapt to it -- and that gives the pleasure that derives from it. On Tue, Jun 6, 2017 at 8:50 AM, alan lavine <cigar...@gmail.com> wrote: > Hi All, > The simple one for sale got me to thinking about doing something similar > with a fixie frame I made at United Bicycle Institute a few years ago. > IIRC you can put 2 closely spaced chainrings up front. Then in the rear > with flip flop hub, you can use a double freewheel on one side and even a > double fixed cog on the other. Is this right? How close do the chainrings > and cogs need to be to avoid having to change the chain length? Can you > use a "crossover" gear, i.e. one chainring with either of the cogs in the > rear (FW or fixed), or do they need to be in the same plane? Will it work > with a standard track dropout or was there something unique on the simple > one/quickbeam? > > Can someone give me examples of the gearing they use? What double crank > works or do I have to make a custom one? My frame was originally built > with a 120 rear but I respaced it to 126...will that work? Are flip flop > wheels available with quick release, and is it OK for fixed gear riding? > I'm wondering how often I would change the gears if I needed a wrench for > the axle nut. > > Lots of questions, sorry, but I'm thinking it would make an interesting > project. > > Thanks in advance, > Alan > NYC > > -- > 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. > -- *30% Supply and Demand discount, listmembers only, on all resume, LinkedIn, and writing services, until Demand equals Supply! And there's more! 10% kickback for any referral resulting in fully paid, list-price contract. And still more! I am offering services in trade for a road bike, or frame and parts, that are period compatible with my AM hub, circa 1937 to 1961. See my website for what I do and what I charge; email for details.* 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 ************************************************************************** ************** -- 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. 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