Shaft driven bike

[benb]

Saw the Biomega Copenhagen reviewed in the latest Cycling Active mag. I'm intrigued. It looks like a brilliant idea for a commuter bike.

 

[Riding in Circles]

Early attempts were very lossy but this one looks pretty cool.

 

[mickle]

The idea has been around for some time....

 

[ianrauk]

I think I remember reading about a bike hire scheme somewhere using them?

 

[benb]

I might be upgrading my commuter some time this year, so this could well be on the list.

 

[Banjo]

I suppose it would do until someone invents a chain driven bike.

 

[byegad]

Big losses inherent in the drive line make this a no go. As has been said it has been around for a good while, IF it was going to work it would have worked the first dozen times it came around. The big efficiency losses and difficult rear wheel removal/replacement kills it every time.

 

[Arsen Gere]

So where do the losses occur?
Why don't we have chain drive cars?
Could this be used with some kind of hub gear like Sturmey Archer or Shimano?

 

[RecordAceFromNew]

Could this be used with some kind of hub gear like Sturmey Archer or Shimano?

It has a Shimano 8 speed hub gear.

But for c£1290 and weighing 14kg for a rigid everything hybrid, I think it has as much chance as becoming a commercial success as all its other shaft drive predecessors, i.e. zilch.

 

[GrumpyGregry]

Saw the Biomega Copenhagen reviewed in the latest Cycling Active mag. I'm intrigued. It looks like a brilliant idea for a commuter bike.

Indeed it does. Looks like a brilliant idea that is. In the flesh it won't be.

 

[benb]

Big losses inherent in the drive line make this a no go. As has been said it has been around for a good while, IF it was going to work it would have worked the first dozen times it came around. The big efficiency losses and difficult rear wheel removal/replacement kills it every time.

Weight is obviously an issue, but I can't see how a shaft loses more energy than a chain. Please explain your thinking.

 

[Zoiders]

So where do the losses occur?
Why don't we have chain drive cars?
Could this be used with some kind of hub gear like Sturmey Archer or Shimano?

If the teeth intermesh closely enough to prevent loss you then get the problem of friction - which brings you back to loss again

If the teeth intermesh losely enough to remove the initial friction...well you are looking at loss again.

Some early cars were chain driven, but then the differential came along, car engines produce far more torque so can overcome the initial friction of shaft drive.

 

[fenlandpsychocyclist]

Most of us can change a tube in 5 minutes flat ... could be a challenge on that!!

 

[Red Light]

So where do the losses occur?
Why don't we have chain drive cars?
Could this be used with some kind of hub gear like Sturmey Archer or Shimano?

The losses are in the two right angled crown & bevel geared turns in the drive from pedal rotation to shaft rotation and from shaft rotation to rear hub rotation.

The other problem they have is shaft wind up under load which makes the pedals feel soggy.

 

[Riding in Circles]

I think the losses on older designs were more a factor of materials and the limits of manufacturing tolerances. This new one may very well be much better.