When I was using a monocog 29er as my winter bike, I had a triple speed: three cogs, three chainrings (the third, lowest gear was used for maximum torque to drive through deep snow without bogging down) . All three combos added up to the same total teeth but the change in angles was enough that I usually had to adjust the wheel in the dropout when changing gears. It worked fine with the disc brakes. -W
On Monday, October 16, 2023 at 11:31:14 AM UTC-7 Patrick Moore wrote: > Thanks, Dave, good to know about the DOX 2-tooth gap fws. > > Back to the question of disc brake and axle movement: the *chain length* will > remain the same; the axle will have to move to accommodate different size > cogs since I don't want a tensioner.* This of course assumes that one is > using horizontal dropouts or track ends; I'd like to stay with that > assumption until it is entirely and definitely ruled out. > > When moving the chain from a 17 to to a 19 t cog and v/v the axle should > have to move only 1/4" or ~6 mm. This movement would be back to front and > v/v. > > The rear caliper on the Monocog is mounted *above* the rotor (actually, > it seems to be a wee bit forward of the rotor centerline). Couldn't you > mount the caliper at top dead center of the rotor? And if so mounted, the > rotor would move only ~3 mm forward or back for a 2-tooth axle shift. > > Could the caliper not accommodate a 1/8" or 3 mm movement fore and aft? If > I have to specify a particular disc brake, let's just say a cable operated > BB7. > > I'll think more about the 2 rings/2 cogs arrangement. I could use, say, a > 36X17 and 34 X 19 for 65" and 55". And certainly, a vertical dropout would > be much easier to use for manual chain shifting than track ends. > > Or one could use a kickback hub: 32 X 21 for a 46" gear in direct, 64" in > 138% overdrive. > > All in all, I think I prefer the QR and horizontal dropout system, and if > disc brakes can't accomodate this then I'll stick to a single speed. [Or, I > could go back to a fixed off road bike where I wouldn't need a rear brake; > but I rather think I want a freewheel. > > *The reason might sound silly but it's a valid one: One reason I took the > Monocog in trade was to have a snow bike. We very rarely get enough snow to > ride in but we do get a few days per year and I like riding in it. A few > years ago I found that wet gummy snow clogged the cassette and rear > derailleur of my Matthews and made the chain skip. Thus the thought of > getting a snow/sand single speed with 3" tires. > > > > On Sun, Oct 15, 2023 at 8:51 PM DavidP <dphi...@gmail.com> wrote: > >> Patrick, I hope I am understanding what you are looking for, but the DOS >> freewheels are still made in the two tooth differential versions; it's only >> the three tooth differential version (16/19) that was discontinued. >> >> I'm not sure if you are looking for DOS freewheels in this situation >> though as these are thread on and not splined >> If you are looking at a different wheelset on this hypothetical bike and >> a standard single speed threaded hub then the DOS will work: >> https://www.whiteind.com/product/double-freewheels >> >> Regarding disc brakes, to Eric's point I know of no way to have the quick >> change of gearing you are looking for with non constant chain length and a >> rear disc. Most single speed disc options that carry the disc with the >> wheel use sliding or swinging dropouts but these are not really something >> you want to be adjusting on the fly. >> >> A double chainring setup really is the simplest. It's a quick change and >> adds a few seconds to the process. >> >> If you adopt a constant chain length dual ring/cog setup, sliding >> dropouts (or an EBB) make the change even quicker as you just drop the >> wheel, swap the cog/ring and reinsert. >> >> -Dave >> >> On Sunday, October 15, 2023 at 10:19:14 PM UTC-4 Patrick Moore wrote: >> >>> Thanks, but I don't want that complication. I want (if I can get it) the >>> simplicity of my Riv customer gofast: QR rear hub, Dingle cog, long >>> horizontal dropouts. I don't necessarily need these means but I do want the >>> same end. >>> >>> On Sun, Oct 15, 2023 at 4:31 PM Eric Daume <eric...@gmail.com> wrote: >>> >>>> The simplest solution is to also use two chainrings, matching the cog >>>> difference (for instance, with a 16/18 Dos freewheel, use 42 and 44t >>>> chainrings). Then the 44/16 and 42/18 have the same chain length, and the >>>> rotor to pad relationship doesn't change. >>>> >>>> Or just use a disc front and a rim brake rear, and a forward facing >>>> horizontal dropout (like typical UJBs have) >>>> >>>> Eric >>>> >>>> On Sun, Oct 15, 2023 at 6:12 PM Patrick Moore <bert...@gmail.com> >>>> wrote: >>>> >>>>> Thinking out loud; help me clarify my thoughts. >>>>> >>>>> I think of devising a Monocog replacement, with 622X76/29X3" wheels, >>>>> but instead of a mono cog, with a duo cog. This hypothetical bike would >>>>> have disc brakes. I don't want to use a chain tensioner, and I prefer to >>>>> take advantage of the greater gear ratio differences between cogs of >>>>> different sizes compared to rings with the same tooth differences, and of >>>>> the consequent smaller axle movement required to adjust chain slack, so >>>>> the >>>>> multiple cogs would be in the back and not on the crank. >>>>> >>>>> On my beloved 1999 Joe Starck Riv Road Custom fixie I use a 17/19 >>>>> Dingle on a Phil hub with a QR axle; it's very easy to stop, flip the QR >>>>> lever, move the chain, align the wheel, and tighten the QR. >>>>> >>>>> That's what I imagine for the Monocog replacement. >>>>> >>>>> 1. Disc brakes. But this bike would have disc brakes. I'd probably not >>>>> need more than a 2-t cog difference, but will your typical caliper/rotor >>>>> setup accept the 1/4" axle movement? (1/8" of axle movement is required >>>>> -- >>>>> so they say; I've never measured it and take it on faith -- to accomodate >>>>> a >>>>> 1 tooth sprocket difference.) >>>>> >>>>> 2. Two cogs. How to get 2 cogs onto a suitable "ss" hub with a >>>>> freewheel. The DIngle isn't made anymore and in any event wasn't made -- >>>>> am >>>>> I right? -- with 2-teeth gaps. The Monocog has a freehub designed to take >>>>> 1 >>>>> single Shimano-spline-type cog; there's no room for a second cog. >>>What >>>>> options does one have to get 2 cogs with a 2-tooth difference onto a hub >>>>> suitable for a QR axle? >>>>> >>>>> I realize that I could just use an old 7 speed Shimano freehub, and I >>>>> might end up doing that, but I'd prefer to have a hub that does not >>>>> require >>>>> a wide stack of spacers. >>>>> >>>>> 3. Axle type and dropouts/trackends/thru-axle holes. I know that long >>>>> forward-facing horizontal dropouts, a QR axle, and a hub with 2 cogs on 1 >>>>> side allows very easy manual shifting, as this sort of shifting goes. I >>>>> am >>>>> also pretty sure that a good builder can use 135 mm OL spacing and still >>>>> give me the stay clearance I need for true 3" tires, so I'm inclined to >>>>> stick with this very old-fashioned wheel attachment method. >>>>> >>>>> But if there are other wheel attachment methods that allow you to >>>>> easily move the chain from one cog to another, I'd be interested to learn >>>>> about them. Sliding dropouts? >>>>> >>>>> Are there any other things to consider ? >>>>> >>>>> Thanks, Patrick Moore, who had a nice ride to church and back today on >>>>> a pretty Fall day riding the Monocog with 72 mm tires and a single 65" >>>>> gear >>>>> despite the bosque trail sand and the rear tire knobs occasionally >>>>> "whisping" on the chainstays (I fixed seatstay clearance with a hammer). >>>>> The Silca Impero with Campy head and the Road-style BB7s pulled by >>>>> non-aero >>>>> DC levers are ironic but in fact work very well. When braking from the >>>>> hoods you simply pull from a bit lower down on the lever; and the >>>>> Impero's >>>>> fat barrel moves lots of air fast into low pressure tires; 13 psi this >>>>> morning and it could have been lower. >>>>> -- >>>>> >>>>> ----------------------------------------------------------------------------- >>>>> Patrick Moore >>>>> Alburquerque, Nuevo Mexico, Etats Unis d'Amerique, Orbis Terrarum >>>>> >>>>> ----------------------------------------------------------------------------------------------------- >>>>> >>>>> Executive resumes, LinkedIn profiles, bios, letters, and other >>>>> writing services. >>>>> >>>>> >>>>> ----------------------------------------------------------------------------------------------------- >>>>> >>>>> *When thou didst not, savage,* >>>>> >>>>> *Know thine own meaning, but wouldst gabble like* >>>>> >>>>> *A thing most brutish, I endowed thy purposes* >>>>> >>>>> *With words that made them known.* >>>>> >>>>> -- >>>>> 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-bun...@googlegroups.com. >>>>> To view this discussion on the web visit >>>>> https://groups.google.com/d/msgid/rbw-owners-bunch/CALuTfgvSea80hxHZ7mMEUxzpaR551T6Q5%3DNLpAvr%2B0QOQ3rh6g%40mail.gmail.com >>>>> >>>>> <https://groups.google.com/d/msgid/rbw-owners-bunch/CALuTfgvSea80hxHZ7mMEUxzpaR551T6Q5%3DNLpAvr%2B0QOQ3rh6g%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>> -- >>>> 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-bun...@googlegroups.com. >>>> >>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/rbw-owners-bunch/CAHFNW5BLmG4%3D1ydCiu5yZ2-Z-2127DHs6%3DuozLQd-a0d7gzY1w%40mail.gmail.com >>>> >>>> <https://groups.google.com/d/msgid/rbw-owners-bunch/CAHFNW5BLmG4%3D1ydCiu5yZ2-Z-2127DHs6%3DuozLQd-a0d7gzY1w%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> >>> >>> -- >>> >>> ----------------------------------------------------------------------------- >>> Patrick Moore >>> Alburquerque, Nuevo Mexico, Etats Unis d'Amerique, Orbis Terrarum >>> >>> ----------------------------------------------------------------------------------------------------- >>> >>> Executive resumes, LinkedIn profiles, bios, letters, and other writing >>> services. >>> >>> >>> ----------------------------------------------------------------------------------------------------- >>> >>> *When thou didst not, savage,* >>> >>> *Know thine own meaning, but wouldst gabble like* >>> >>> *A thing most brutish, I endowed thy purposes* >>> >>> *With words that made them known.* >>> >> -- >> 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-bun...@googlegroups.com. >> > To view this discussion on the web visit >> https://groups.google.com/d/msgid/rbw-owners-bunch/3b0606d2-3988-4268-88fe-65afccb66cf2n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/rbw-owners-bunch/3b0606d2-3988-4268-88fe-65afccb66cf2n%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > > > -- > > ----------------------------------------------------------------------------- > Patrick Moore > Alburquerque, Nuevo Mexico, Etats Unis d'Amerique, Orbis Terrarum > > ----------------------------------------------------------------------------------------------------- > > Executive resumes, LinkedIn profiles, bios, letters, and other writing > services. > > > ----------------------------------------------------------------------------------------------------- > > *When thou didst not, savage,* > > *Know thine own meaning, but wouldst gabble like* > > *A thing most brutish, I endowed thy purposes* > > *With words that made them known.* > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. 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