brain teaser

[jamabikes]

ahhhhh this has been messing my head up for days!

now without actually trying it, what would happen if you put two chains on a bike?

one at 32:16 and one at 32:32.

would the wheel lock up?

would it turn?

would it be easy to turn?

would it be hard to turn?

which ratio would be king?

but surly it cant turn?

:evil: :evil: :evil: :evil: :evil: :evil: :x :x :x :x :x

 

[BerthaPog]

Assuming both pairs of rings/cogs are connected and no freewheels are involved - not a great deal - might get a small amount of movement rocking back and forth, but they would not rotate.

For one of the pairs, the axles will try run run at the same rotational speed, for the other the rear axle will try and rotate at twice the speed - unless there is some way to allow slip between the two this can't happen.

One way to make it work (and it's cheating more than a little) take a second 32 tooth "cassette cog", remove half the teeth. Technically only 16 teeth, but it would rotate.

Another way (probably easier), one running 32:16, and the other running 42:21 - would look very odd, and possibly have chain tension issues but would be quite cool...

 

[Grannygrinder]

One way to make it work (and it's cheating more than a little) take a second 32 tooth "cassette cog", remove half the teeth. Technically only 16 teeth, but it would rotate. (quote)

Removing the teeth wouldn't effect the diametre, which is effectively the thing that determines the gearing.
So i don't think anything would change there

What could possibly make you want to do such a thing anyway :shock:

 

[BerthaPog]

One way to make it work (and it's cheating more than a little) take a second 32 tooth "cassette cog", remove half the teeth. Technically only 16 teeth, but it would rotate.

Removing the teeth wouldn't effect the diametre, which is effectively the thing that determines the gearing.
So i don't think anything would change there

Hence why it's a big cheat (that would work) - it's just running two chains over two pairs of 32:32 cogs, with one of the cogs with half its teeth missing.

What could possibly make you want to do such a thing anyway :shock:

Too many spares and an inquisitive mind - without the crazy ideas that don't work, you don't get the crazy ones that do.

 

[REKIBorter]

I think there is only one way to find out. Do it!

 

[jamabikes]

i like to set myself these little teasers

if it was set up on a freewheel, would it turn backwards still?


arghhhhhhhh

it all started with thinking about fitting two chains to the single speed...kinda hd primary style....

 

[FMJ]

it all started with thinking about fitting two chains to the single speed...kinda hd primary style....

If the drive to jackshaft are both 32 and jackshaft to rear are 32-16 it would be the same effective ratio as running a conventional 32-16. You could run any similar combination on the jackshaft and it would always work out to be 32-16. It's when you start mixing them up (the two jackshaft cogs) that things start to go out the window. By staggering jackshaft cog sizes, John Howard's speed record bike was (effectively) 400 gear inches.

 

[jamabikes]

i meant two chains parallel but now a jack shaft.... hmmmmmmm