Re: [RBW] Best way to arrange 2-cog manual shifting for "single speed" disc braked bicycle

[Wesley]

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  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  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  
 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 te

Re: [RBW] Best way to arrange 2-cog manual shifting for "single speed" disc braked bicycle

[DavidP]

Yes, chain length remains the same in all cases - I guess what I meant to 
say was 'rear center' (distance between bottom bracket and axle).

It's entirely possible a rear disc might work well enough over that ~3mm 
range. I've never owned a disc braked bike with horizontal dropouts 
allowing the axle to move independent of the caliper so I'm not sure about 
the tolerances in setup.

On Monday, October 16, 2023 at 2:31:14 PM UTC-4 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  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  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  
 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 

Re: [RBW] Best way to arrange 2-cog manual shifting for "single speed" disc braked bicycle

[Patrick Moore]

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  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  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  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 bra

Re: [RBW] Best way to arrange 2-cog manual shifting for "single speed" disc braked bicycle

[DavidP]

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  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  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

Re: [RBW] Best way to arrange 2-cog manual shifting for "single speed" disc braked bicycle

[Patrick Moore]

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  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  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
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>> To unsubscribe from this group and stop receiving emails from it, send an
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>> To view this discussion on the web visit
>> https://groups.google.com/d/msgid/rbw-owners-bunch/CALuTfgvSea80hxHZ7mMEUxzpaR551T6Q5%3DNLpAvr%2B0QOQ3rh6g%40mail.gmail.com
>> 

Re: [RBW] Best way to arrange 2-cog manual shifting for "single speed" disc braked bicycle

[Eric Daume]

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  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.*
>
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