BluesDaddy

These are the strange ideas I concoct when I have nothing better to do... Has anyone tried a, for lack of a better term, "multi-single speed"? This would be a close-ratio, maybe straight-block freewheel and it would have to be a frame with horizontal dropouts. I wonder what the maximum range of cog sizes could be used and still keep chain tension using only the the forward-aft movement of the rear wheel in the dropouts. Then, when on the road, gearing changes would be made by stopping and moving the wheel, old-school style.

John E

You can figure out the cog size range from the length of the dropout slot -- every inch of movement will compensate for 4 teeth. Have a look at some of the old Campagnolo Combio Corsa rigs, which I think got as far a 14-22 5-speed freewheel with no tensioning device other than the quick release mechanism. You could even combine this concept with a 46-49 ringset for half-step gearing.

Since I like my derailleurs, my main reaction is "why bother?"

illwafer

i know someone who has a 2 speed. a double upfront and 2 gears in back. this allow him to use the same chain length and have a small gears to get up long hills.

BluesDaddy

Cool, that is good info to go on... as for the "why bother?" Well, I know it doesn't makes sense but it will be a fun exercise. Also I'm looking for unique ways to eliminate external shifting for a winter bike. I've had my rear derailleur ice up in the past. Ultimately I would like to combine this idea with a 3-speed hub.

BluesDaddy

Another great idea!

ColonelJLloyd 

Rivendell did this with their Quickbeam (track dropouts). An ugly double up front and a White Industries ENO two-speed freehweel. Four gears.

sauze

wow and ugly double indeed, I love pretty much everything else about that bike / gearing.

ColonelJLloyd 

I'm sure the bike pictured cost every bit of $2,000.

sailorbenjamin

Somewhere on Sheldon Brown's site he talks about a friend who's got a triple in front and a triple in back and he runs it fixed. The difference between the front gears is the same as the difference between the back gears so the chain length is the same and the chainline is always good.

nlerner

Dingle cog for fixed gears: https://surlybikes.com/parts/dingle_cog/



A few companies make a freewheel version, including White Industries and ACS:



Neal

randyjawa 

Is this one of those Zen riddles?-)

StanSeven

I've been looking at an occassional commuter. This gives me something to consider.

rothenfield1

You guys seldom cease to amaze me with your creativity. Keep thunking; it's very entertaining, for the unimaginative such as myself, to see people who push the boundaries of what a bicycle can be.

shipwreck

I did it with an AW hub. Twenty and a sixteen. Don't change it much, unless I am doing a multi day ride that changes terrain from day to day, its not hard to move, but not something that you do right in front of a hill.


This is a hard ridden bike, so exuse the oil and grime.
The dust plate is in place, some folks assume I had to remove it, but everything worked fine.

surreal

Pretty harsh, calling the venerable sugino xd "ugly". The ugliness, imo, is coming from the bash-ring part of it. Otherwise, the crank'd look pretty nice for a 5-bolt 4-arm.

-rob

sailorbenjamin

Um.. What a great idea. I have a 46-49 crankset that's just begging for one of these

RFC

I used a conversion kit to build a 2 speed on my "path racer." One gear for street and one for dirt trails.

BluesDaddy

Okay, that brings up something I hadn't thought of... Where is the "freewheel" element of a Sturmey-Archer, inside or at the cog? If it's inside, then does that mean any fixed cog (or double cog like the one nlerner posted) will work?

pastorbobnlnh 

On a SA hub it freewheels on the inside.

Joel, I might have a very close ration freewheel you could try this on.

YoKev

The freewheel element of the AW is in the hub itself. Sometime in the mid-50's, Sturmey Archer stopped using a threaded on cog and switched over to a circlip retained cog. Someone else should verify that you can use a track cog on the older ones, but I have been led to believe that you can.

Road Fan

But it's only two if you ignore the anti-crosschaining rule ....

Road Fan

Considering the old Cambio, it's more like they're rediscovering old boundaries that were left behind.

The icing is a consideration, but what about a shield on the rear mech, and a front splash guard, if fenders are beyond the pale.

Italuminium

Well, build one, then climb up a mountain, try to loosen the wingnuts in a blizzard to adjust gears, bust your knuckles and invent the quick release. It has been done before

ColonelJLloyd 

That's the whole point, Rob. That is the crank they sell with the Quickbeam. The bashguard is integral. I think it's ugly. It's just an opinion, dude.

As for being harsh; it's an inanimate object. It has no feelings to hurt. I told it that its mother is a hamster and its father smells of elderberries. No reaction. Nothing.

pastorbobnlnh 

Up close, it looks better than it did at a distance, IMO.