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Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

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Old 10-05-10, 01:29 AM   #1
ppc
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Amazingly clever shift-once two-speed fixie drivetrain arrangement from the 80s

I just came across this page that deals with the bizarre idea of running two chains on a bike, when I read the following nugget at the end of the page:

However it got me thinking about another bike I'd seen with a similar set-up but this one made a lot of sense. In 1982 Canadian rider Jocelyn Lovell rode the kilometre time trial at the World Championships in Leicester, England using a bike with two transmissions. His arrangement gave him two gear ratios, a lower gear to get away from the line and a higher gear that kicked in after about seventy metres. His ride in Leicester wasn't as good as he hoped for but the transmission worked well and it could not be faulted by the UCI commisaires.



Jocelyn's bike had a freewheel sprocket on the normal right hand side and a fixed sprocket on the left hand side. As he moved away from the line he drove through the RH sprocket and the left hand fixed sprocket began to unscrew from the hub. It being of smaller diameter it turned at a slower rate than the RH sprocket and being on the "wrong side" of the hub it would naturally unscrew. After about seventy metres the LH fixed sprocket came up against the lockring and at that point drive was through the LH side and the RH sprocket freewheeled. The distance traveled before the higher gear engaged could be adjusted by setting the position of the lockring. The bigger the space between lockring and sprocket at the start the longer the distance before the higher gear engaged.
Jocelyn experimented for some considerable time to come up with a combination of sprockets and chainrings that would not only give two suitable ratios but that would need chain lengths that would be at the correct tension. He settled on a low gear of 42x13 (87.2") and a high gear of 53x15 (95.4")


Wow, that is incredibly clever and a very elegant working around (or within?) the UCI rules. Lovell was a genius. I'm almost tempted to try it myself to see what it feels like

(There's just a small misunderstanding of how the system worked in the above explanation: the LH sprocket unscrews because it is smaller and thus spins *faster* than the wheel in the first 70m, not slower)
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Old 10-05-10, 02:00 AM   #2
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That's pretty ingenious.

I've seen a double freewheel setup using a standard freewheel on the right side of the cranks combined with a LSD (left side drive) BMX freewheels for the left side setup.

LSD exists because some BMXers want the chainring on the left side to get it out of the way if they like to do grinding tricks on the right side.
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Roadies can run tempo all year as that's what humans were designed for. If you want to be a cheetah, lay around and lick your paws more.
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Old 10-05-10, 03:40 AM   #3
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That's pretty ingenious.

I've seen a double freewheel setup using a standard freewheel on the right side of the cranks combined with a LSD (left side drive) BMX freewheels for the left side setup.

LSD exists because some BMXers want the chainring on the left side to get it out of the way if they like to do grinding tricks on the right side.
Nahhh man, LSD exists to bring us all together.... man.
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Old 10-05-10, 04:51 AM   #4
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damn jets, you beat me to it lol.
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Old 10-05-10, 01:16 PM   #5
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Interesting. Any video of this in action?
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Old 10-05-10, 02:02 PM   #6
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http://www.youtube.com/watch?v=hSoMkOhvaUQ three chains, three chain rings,three cogs!
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Old 10-05-10, 07:45 PM   #7
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tempted to try this
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Old 10-05-10, 07:50 PM   #8
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if every edge really mattered, why would you want to uselessly spin a freewheel for the bulk of the race?
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Old 10-05-10, 07:56 PM   #9
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More of an edge gained by quicker acceleration.
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Old 10-05-10, 08:08 PM   #10
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did he win?
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Old 10-05-10, 08:35 PM   #11
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Everybody wins in a TT
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Old 10-06-10, 08:08 AM   #12
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http://www.youtube.com/watch?v=hSoMkOhvaUQ three chains, three chain rings,three cogs!
But unrelated to the setup described by the OP as far as I can tell. What would be the point of such an apparently identical and redundant drivetrain, anyway?
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Old 10-06-10, 10:01 AM   #13
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funny, my bro and i were just joking talking about putting on 2 cranks and 2 cogs just for kicks when i was changing out my drivetrain.
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Old 10-07-10, 10:51 AM   #14
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But unrelated to the setup described by the OP as far as I can tell. What would be the point of such an apparently identical and redundant drivetrain, anyway?
More surface area contact with the mechanism driving the wheel forward? Kind of like the idea between turning a rolling-pin pulley with a string, vs pulling it with a wide belt.

Or something like that.

I dont know Im just making a hypothesisisisness.
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Old 10-07-10, 11:25 AM   #15
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More surface area contact with the mechanism driving the wheel forward? Kind of like the idea between turning a rolling-pin pulley with a string, vs pulling it with a wide belt.
This would only be useful if a single chainring/cog was slipping, which it wouldn't be. I imagine the triple chainring/cog setup is just a vanity thing.
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Old 10-07-10, 02:17 PM   #16
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3 chains on one side are useless, and so are 2 chains on both sides. One chain is plenty strong to withstand the effort of any cyclist. Mechanically, only one cog can be fully screwed onto the hub, and only one of the chains can be fully engaged anyway.

So yes, it's all vanity.
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Old 10-07-10, 05:23 PM   #17
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But unrelated to the setup described by the OP as far as I can tell. What would be the point of such an apparently identical and redundant drivetrain, anyway?
Hmm i posted because it has multiple drive chains i guess and there is no benefit...
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Old 10-07-10, 06:00 PM   #18
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did he win?
but r u going to the alleycat? bring your under armor, and aerospokez
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Old 10-07-10, 06:18 PM   #19
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i need a left side freewheel for a fast start.
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Old 10-08-10, 01:19 AM   #20
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When I brought my double freewheel to my lbs, he said back in the 80s or 90s some BMX racers had double freewheels with some kind of "shift once" mechanism to get a quick start. That's what I thought you were talking about.
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