Shaft Drive

[Deleted member 26715]

Still a long way from the goal post, they have to work out how to move it across the cheese grater to get different gears, it's not simply having the teeth(?) going outwards as they currently have it, as they will not be inline with each other. Also as pointed out, how much power/leg force could you put through it.

 

[Alan O]

Still a long way from the goal post, they have to work out how to move it across the cheese grater to get different gears, it's not simply having the teeth(?) going outwards as they currently have it, as they will not be inline with each other. Also as pointed out, how much power/leg force could you put through it.

I'd wonder about what happens when the teeth start to wear too. A chain has tension to keep it tightly engaged with the teeth, but how would a pinion behave?

 

[Deleted member 26715]

I suspect that they are currently relying on the multitude of bearing which means wear will be minimal

 

[Tim Hall]

Still a long way from the goal post, they have to work out how to move it across the cheese grater to get different gears, it's not simply having the teeth(?) going outwards as they currently have it, as they will not be inline with each other. Also as pointed out, how much power/leg force could you put through it.

There's another video on Youtube where the guy from the inventors talks about shifting. The shaft will have a battery, electronic brain and linear actuator in it. The cassette will have a series of shifting gates. When the rider presses the shift button the electronic brain waits until the shift gates are in the right place then changes gear.

 

[lazybloke]

The bikes at a French Centerparcs (Les Bois-Francs) a couple of years ago were all shaft drive. I'd taken my own bike so I can't provide a review.

 

[Gravity Aided]

Assuming this could be made to work, or using a 8 speed IGH, I could see where this could be a boon on a folding bike. Weight and inefficiency are always the downfall here. Columbia made many a shaft drive bike back in the day. (1890s) and then there's the Dynamic Runabout 7.
http://www.bikeiowa.com/Review/1590/a-quick-look-at-dynamic-bicycles-shaft-drive-chainless-bikes

 

[Globalti]

Mobikes and their ilk are shaft drive but they are heavy and slow.

The design shown in the video above will need to be much stronger and hence heavier to keep everything in place under heavy torque, as in climbing hills for example.

 

[Deleted member 26715]

Sadly thinking about this out on a ride yesterday, the only way I can see it working is instead of there only being 1 drive from the shaft to the rear 'cog' there are 8 drives all constantly turning but only 1 engaged at any 1 time, the trick will then be to design something that can seamlessly shift between 2 'cogs'. F1 & some road cars have a double clutch system, where it effectively is in 2 gears at once but only 1 is driving but doing this under an acceptable weight will be difficult I suspect.