Chainless bike

[Rhythm Thief]

I don't understand why you say that. I have no axe to grind either way here, but I have to say that in over 25 years (on and off) of reasonably regular cycling, I've never had the slightest problem with a standard derailleur and chain system. Certainly no problems big enough to make me think "why, blast this infernal chain to buggeration! If only there was some kind of chainless bicycle that would alleviate the need for this oily Judas!"

 

[Fab Foodie]

Hmmmmmmm! Just as I thought, the shaft drive inefficentices that everyone are going are just a myth.

I don't dispute that a bicycle's chain drive system is both effective and efficent. However, in these enlightened times, I think that the majority has been blinkered by past poor quality and performing systems. With the availability of modern materials and excellent quality bearings, that not only is a shaft drive system effective, but it is also the way forward.

http://en.wikipedia.org/wiki/Shaft-driven_bicycle

 

[mickle]

Heavier, less efficient, more expensive, requires a dedicated frame (with perfect alighnment) and may only be used with infernal hub gears whose gear ratios cannot be changed. Any one of these reasons is enough for me to dismiss shaft drive for cycles.

And ugly.

 

[Hilldodger]

Heavier, less efficient, more expensive, requires a dedicated frame

Sounds like a lot of recumbents

 

[Niall Estick]

OK, So what are, and where are the inefficencies in a shaft driven bicycle?

I'm no engineer but look at the number of ways a shaft drive has to convert rotational forces. A chain is relatively direct in conerting power at the crank to power at the wheel.

 

[Hilldodger]

A shaft drive will always work with the same efficiency.

A chain drive requires regular cleaning and maintenance to be kept in top condition and working properly. And a lot of people do't do that.

 

[byegad]

Like airless tyres shaft driven bikes keep getting reinvented. The losses are in the bevel gears needed to translate the rotation through 90 degrees art each end of the shaft. There is also a recurrent problem with rear wheel removal and refitting in getting the rear bevel engaged correctly, any misalignment in the engagement comes at a high efficiency cost.

 

[jack the lad]

One reason it may never have caught on is that, as far as I can see, very little thought has gone into original bike design which takes full advantage of chainlessness. They are just normal bikes but with shaft drive instead of a chain, so there's no benefit to trade off for the extra weight, loss of efficiency and extra difficulty in mending p*nctures. The classic 'solution looking for a problem'.

However, there is at least one problem that chainless bikes might be a solution to - One of the main reasons why I bought a folder was to stop chain muck getting all over me and over Mrs J's car from having to remove and refit wheels when I carried a full size bike to commute the few miles between her work and mine. I chose a Brompton over other options in large part cos all the mucky bits end up in the middle out of the way.

So there's a potential market with people like me for oil stain free chainless folding bikes, especially if you can make a realistic claim of 'maintenance free'. Run the shaft drive inside a single-sided chainstay and you deal with the wheel removal problem and add very little extra weight. Go for a single sided front fork too while you are at it and you could have a very narrow folded package.

Single sided chainstays and forks would make a lot of sense for making p*ncture repair easier on full size non-folding bikes too, especially with hub gears. Although there's no reason why it couldn't be done with chain driven bikes, you don't get the 'clean' benefit unless you fully enclose the chain. That always seems to look old-fashioned and even if you get over that it must result in a necessarily chunky appearance. This would be even more dominating on a small wheel folder and you wouldn't get such a potentially compact fold as you could with a shaft drive.

There are people who would trade some efficiency in return for perceived style points or who would be unconcerned about maximising efficiency if there were other selling points to attract them to a bicycle. If efficiency was high on the list of essential bicycle features there wouldn't be so many people riding round on heavy full suspension mtb's with under-inflated chunky tyres!

 

[skwerl]

You're all wrong. After all, to quote Terry D from the website - "The bike is truly one of the (if not the) nicest bikes available to ride and look at on the market today".
What more evidence do you need?

 

[drkickstand]

There is a lot of positive info and feedback on the belt drive systems on folding bikes. I understand that a lot of the main a manufacturers have offerings in the pipeline for full size bikes.

 

[Hilldodger]

Riding a chainless bike didn't stop Major Taylor - one of the all time great cyclists - from being successful

 

[mickle]

Riding a chainless bike didn't stop Major Taylor - one of the all time great cyclists - from being successful

Yeah but he was probably successful in spite of the drivetrain.

 

[tyred]

I don't like the idea of a shaft drive for the reasons mentioned but would be interested in trying a toothed drive belt, similar to those used for the camshaft in most overhead cam engines. It should work efficiently with hub gears (which I like anyway). The only bug with the normal diamond framed bike is how the hell do you get the belt of and on as the chainstays need to pass through it?

 

[jack the lad]

When I bought my Mercedes I wanted to find out when the cambelt change was required as it would probably be many £££s and due quite soon. However, I discovered that they use a proper metal chain which normally outlasts the life of the engine (and bear in mind that many mercs go to 300,000 miles plus).

If this is the case with a car engine, what benefits can there possibly be in using cambelts to drive bikes, instead of proper metal chains?

 

[tyred]

There are a few differences. The timing chain of an engine is completely sealed from the outiside world for one thing. I've also seen engines where the timing chain has broken at relatievely low mileage (a BMW 325TD that my uncle had being one such expensive case). A cam belt drive should be much quieter and smoother than a chain drive, doesn't need oiled and shouldn't stretch in use. Even safe and sound inside the engine, chains stretch (listen to the racket from an old BMC A series/Ford Crossflow or Peugeot/Simca engine can make if you don't believe me). If the tension is set right, the belt will deteriorate with age rather than use. Also, for people who ride in the rain, it won't rust or need to be covered in messy oils to prevent it.