You didn't think of it because you're sane.
How could it not be disallowed if it's two gears on the same track bike at once? I'm guessing it only works if the official doesn't notice the gears are different.
At the start of a handicap track sprint once I was passed by a broken chain that had left the bike that started behind me and was sliding forward in a straight line on the track surface and going faster than I could ride.
Mitch Harris Little Rock Canyon, Utah
On 1/11/06, Mark Bulgier <Mark@bulgier.net> wrote:
>
>
> Kurt Sperry wrote:
>
> > Someone mentioned earlier in this topic dual sided
> > drivetrains for vintage racing bikes and their being
> > subsequently outlawed I think. If so what were the
> > alleged advantages?
>
> I heard of a kilo timetrial or pursuit bike with fixed gears of two
> different gear ratios. Obviously it's an advantage (however small) to
> be able to accelerate briefly in a lower gear, then switch to a higher
> gear - automatically without letting go of the bars.
>
> How they achieved this was by threading the smaller rear cog on the
> right side, but not all the way (maybe just a turn or to onto the hub),
> with no lockring. The chain on the left, the side with the larger cog,
> had a purposefully-weak link, a piece of light gauge wire instead of a
> chain link IIRC.
>
> The weak link was placed on the chainring at the start of the race,
> forward of those 3 or 4 teeth at the top of the ring that do all the
> pulling. So when the rider started, the weak link traveled back along
> the unloaded under-side of the chain run, where its weakness didn't hurt
> anything.
>
> Meanwhile the smaller cog on the right is turning faster than the hub is
> turning, because of the difference in the gear ratios. It is threading
> on to the hub due to the right-hand thread.
>
> The amount the cog was backed off to begin with was carefully calculated
> so that it would fully tighten against the hub shoulder just at the very
> moment that the weak link on the left was coming around to the top of
> the rear cog, where it would finally have to bear some load. The weak
> link pops, the chain falls to the track, and the rider continues
> accelerating, now in a higher gear, and with less weight to boot! His
> holder or starter would have to get the chain off the track before the
> next lap, but due to the constraints of the length of chain, it wouldn't
> be very far down the track.
>
> I don't remember who came up with this (some guy named Rube I think, I
> forget the last name), nor do I remember if it was ever allowed in
> competition. I doubt it though - seems like cheating to me. Officials
> have leeway to disallow something that seems unsporting even if it isn't
> specifically forbidden in the rules. I'd bet (if I were a betting man)
> they didn't allow it in any important competition.
>
> Don't I wish I'd thought of it first though!
>
> Mark Bulgier
> Seattle WA USA