Shaft Drive

[Gubbins]

Just looking through some bike adds and came across an electric shaft drive model.. More searching found a few more so I was wondering why we dont see this as it seems a good idea when coupled to a hub geared wheel.. Or is it me that isnt looking in the right places?

 

[flecc]

There have been a few attempts over the last ten years to get these to sell well in both unpowered and electric forms, but they all seem to fail.

The inflexibilty is a restriction, originally only for the Nexus 7 speed hub and later an 8 speed version, the lack of a wider choice or ability to change the overall gearing are serious impediments.
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[jwm]

I have one of the Bicycles4u Elegance shaft drives, nice bike for the money... they were £650 before christmas! The shaft drive being one of the main reasons for getting it, tired of cleaning and replacing chain/rear cassettes. Drive is nice, odd having no chain clatter though. Only restriction I have found with this particular model is the three speed hub, but as another of my aims was to slow down a bit and stop racing, to save my knees you get use to it.

John

 

[Emo Rider]

One of the draw backs with shaft drive is the loss of power delivered through the drive train. Everytime a power delivery system changes direction there is a loss of power. Chain or belt drive will always be more efficient.

 

[RobF]

One of the draw backs with shaft drive is the loss of power delivered through the drive train. Everytime a power delivery system changes direction there is a loss of power. Chain or belt drive will always be more efficient.

Inevitably, the maker of a shaft drive system will give you an argument:

"Testing has shown that the efficiency of our shaft-drive system is about 92%-94% without regular maintenance. According to Dobrovolsk and Others' "Machine Elements Textbook", the peak efficiency of very expensive chain systems ranges from 95% to 97% (chain-rings in same diameter, chain in perfect alignment and chain in permanent ideal tension). However, typical, averagely maintained chain-derailleur bikes range in efficiency from 75% up to 85%, and can often skip and/or jump gears. This means that for every pedal stroke, shaft drive bicycles will perform more consistently and shift gears more smoothly than a chain bike that is not meticulously cleaned, adjusted and lubricated. This translates into more consistent performance without worrying about adjusting chain tension, aligning chains and derailleurs, and regularly cleaning and lubricating the chains and chain-rings."

http://www.sussex.com.tw/faq.html

 

[Gubbins]

I had a shaft drive motorcycle once.. but of course the gearbox was before the shaft not after it....
Is there a case for a rethink here. ...

 

[Emo Rider]

Inevitably, the maker of a shaft drive system will give you an argument:

"Testing has shown that the efficiency of our shaft-drive system is about 92%-94% without regular maintenance. According to Dobrovolsk and Others' "Machine Elements Textbook", the peak efficiency of very expensive chain systems ranges from 95% to 97% (chain-rings in same diameter, chain in perfect alignment and chain in permanent ideal tension). However, typical, averagely maintained chain-derailleur bikes range in efficiency from 75% up to 85%, and can often skip and/or jump gears. This means that for every pedal stroke, shaft drive bicycles will perform more consistently and shift gears more smoothly than a chain bike that is not meticulously cleaned, adjusted and lubricated. This translates into more consistent performance without worrying about adjusting chain tension, aligning chains and derailleurs, and regularly cleaning and lubricating the chains and chain-rings."

http://www.sussex.com.tw/faq.html

This is very well worded double speak from a company that wants to sell its product. Most of what they say is true but when the actual, real time, side by side comparisons are made, the chain drive will win out with performance figures using the same final drive. It is true that the shaft drive is the more trouble free and consistant requiring less maintenance. However they compare their performance to a chain and mech worse case senario. Don't know about you guys but I and most people keep their kit in somewhat good condition or else they are not riding a wonky bike.

I had both shaft and chain drive motorcycles. I would not trade the shaft drive for the chain drive mainly because of the maintenance. But I do not have 98 horse power delivering power to the wheel on my bicycle so I'll stick to chain drive.

 

[RobF]

I had a shaft drive motorcycle once.. but of course the gearbox was before the shaft not after it....
Is there a case for a rethink here. ...

Already rethunked to a point in the shape of the Pinion bottom bracket gearbox.

This pic has one connected to a belt drive, but I'm fairly sure I saw a pic of one somewhere connected to a shaft.

There are still lots of small bike makers in Germany and Holland, so these things can be hard to track down - particularly if you don't read German.

http://pinion.eu/p1-18-getriebe/

 

[Gubbins]

The pics make this look fascinating. .... Might try a translator tomorrow. ..

 

[RobF]

The pics make this look fascinating. .... Might try a translator tomorrow. ..

Also have Googly around KTM - they make a couple of bikes with the Pinion gearbox.

 

[flecc]

Inevitably, the maker of a shaft drive system will give you an argument:

http://www.sussex.com.tw/faq.html

Their argument aginst chain is rubbish of course, starting by distorting the true efficiency of a new chain system and pretending that perfect chain alignment is essential, again very untrue.

We get similar distortions by the belt drive promoters.
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