Bio pace in 1990?

[Woz]

Makes no sense to me either!

As the longer diameter move from the vertical axis to the horizontal it is still pulling the same amount of chain.
Also, the pedals still remain in their usual round configuration so i don't understand how it would feel any different to pedal?

All very confusing! :?

With a true ellipse (which biopace isn't, IIRC) the chain wrap remains the same, but gear inches do change. Think of it as the chainring constantly morphing from a big ring which is close to the rear wheel to a small ring which is further away.
Same length chain, different gears.

That make sense?

So....how do they change gear but they work on a SS or Fixed Gear. Do teeth fall off and jump on the while you pedal?

No, as the size of the chainring (yet, as I explained above, not necessarily chain-wrap) effectively changes, the number of gear inches -- the 'gear' -- also changes. I don't believe any actual witchcraft is required.

Like 27 gear inches and a bit, then not quiet 27 gear inches twice per revolution? The plot thickens.

 

[thecannibal]

Makes no sense to me either!

As the longer diameter move from the vertical axis to the horizontal it is still pulling the same amount of chain.
Also, the pedals still remain in their usual round configuration so i don't understand how it would feel any different to pedal?

All very confusing! :?

With a true ellipse (which biopace isn't, IIRC) the chain wrap remains the same, but gear inches do change. Think of it as the chainring constantly morphing from a big ring which is close to the rear wheel to a small ring which is further away.
Same length chain, different gears.

That make sense?

So....how do they change gear but they work on a SS or Fixed Gear. Do teeth fall off and jump on the while you pedal?

No, as the size of the chainring (yet, as I explained above, not necessarily chain-wrap) effectively changes, the number of gear inches -- the 'gear' -- also changes. I don't believe any actual witchcraft is required.

Like 27 gear inches and a bit, then not quiet 27 gear inches twice per revolution? The plot thickens.

Yeah, that's it. I had an Egg ring on a old trials bike (until I sold it recently) that was so radical it must've almost halved/doubled the gear inches on each rotation.

 

[Neil]

I don't believe any actual witchcraft is required.

2 minutes, 54 seconds.

Sorry, Hudson Hawk inspired gag, there.

 

[elPedro666]

As stated, Shimano had the rings at 90degrees to the logical :? The idea of spinning quickly through the 'weak' spots of the stroke (top/bottom) then powering through the main stroke seems sensible though. Would like to try a set up sometime Egg-rings were 90' to Biopace I believe, as are modern Rotor Aguila(?).

 

[elPedro666]

And I'm not sure you can biopace a ss, although it rings a bell that the great Sheldon pulled it off, just because he could I think... Sprung tensioner maybe, or perhaps it just doesn't make enough difference to the chain length to give too much slack.

 

[Acei]

I'm confused :? Am I alone?

 

[thecannibal]

I'm confused :? Am I alone?

Nah, think you have plenty of company