My understanding of the dual drivetrain setup is that it had a lower gear on a freewheel attached to one side of the hub, and a higher gear fixed cog on the other side. The fixed cog is started on the thread but still several revolutions from being seated against the hub. The difference in ratios means that the fixed cog is screwing itself on as the rider starts in the lower gear and once the fixed cog seats on the hub it takes over and the freewheel begins to freewheel (as freewheels sometimes do) due to the lower ratio relative to the fixed side of the drivetrain. Clearly this would require some left-hand threaded parts for the left side drivetrain. I think the rider coudl find tune the time/distance that it took to engage the high gear using ratio difference and the extent to which the fixed cog is started on the hub thread.
The benefit is a lower gear for a faster start in a track TT event (kilo, as I recall).
I think this is in the archives somewhere. I think I learned about it on CR.
FWIW.....
Tom Dalton Bethelhem, PA USA
Hi all,
There is a bicycle with a handlebar/fork combo like that on display in t he transportation section at the Ontario Science Center in Toronto Canada. The Science Center's bike was donated by Canadian cyclist Jocelyn Lovell. I forget which discipline of track racing his was built for (or who built it ) but I do remember he had a chain on both sides and the gear ratio was dif ferent. There was some sort of automatic clutch mechanism in the hub that k icked out of one gear and into another as a certain rmp. A bike that's both fixed gear and not a single speed! If any one can find online links to pho tos I'd like to have another look at the bike please and thank you. It's on -topic as Jocelyn stopped riding in 1983 when he had an accident.
Cheers, Peter Schwar Montreal, Canada ________________________________________________
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