# Belt and Shaft driven bikes?



## Bigsharn (5 Sep 2012)

I realise that I essentially have a choice between hub gears or Singlespeed if I go this route and that's fine.

Because I destroy bikes, not ride them (I do proper maintenance, but I go through chains and spokes like you wouldn't believe) I've been looking for something a little bit more difficult to destroy and came across the two options

I was just wondering if people had any experience with a <£1k bike (My budget... Ideally it'll be a 5 year bike), that had either of the two systems fitted? How do they handle differently to chains and are there any troubles in adding carry racks?

Cheers
Sharn


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## biggs682 (5 Sep 2012)

i have been using a belt driven 7 speed nexus hub geared Mercedes for commuting on for last month , a very solid heavy bike but nice and comfy for commuting


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## HovR (5 Sep 2012)

I've heard shaft driven bikes are a bit naff. Apparently not very efficient.


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## TheDoctor (5 Sep 2012)

I'd look at how you manage to wreck chains.
Belt drives are either pricy or rubbish, and shaft drives are heavy. And rubbish.


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## Red Light (5 Sep 2012)

You'll struggle to find a shaft drive bike and they are not very efficient and suffer from shaft wind up which makes them odd to pedal in earnest.

Gates belt drives are good but you will struggle to find a bike with one within your budget. You might see if you can find anyone with last years Trek Soho Deluxe bike which came in around £800 last year but I think is now discontinued.


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## tyred (6 Sep 2012)

Consider a bike with a proper full chaincase and chains will last for decades.


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## byegad (25 Sep 2012)

Shaft drive is an 'innovation. that appears every ten years or so. It has huge inefficiencies, you are turning the drive through 90 degrees twice. It also has issues with resetting the rear end after wheel removal.

The reason why they are rare is that they are indeed naff.


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## Linford (25 Sep 2012)

Can only make a comparison with motorbikes and cars for the efficiency of the vehicles

I had my old m/bike (ZX6R - 600cc chain drive supersports) was run up on the dyno when I first got it about 10 years ago, and it was producing 99.7BHP at the back wheel, and about 112bhp at the crank.

I went to a scoobynet rolling road day a couple of years laters, and they put a standard Subaru Imprezza Turbo2000 on the rollers. It was giving 110bhp at the wheels, and a claimed 220bhp at the crank.

Chains are by far the most efficient method of power transfer.


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## Drago (25 Sep 2012)

The crank figure is little more than a computer aided guess. Unelss the motor is dyno tested on a bench it is impossible to achieve an accurate crank figure. I would contend that if a Scooby is so ill it is only giving 110 at the tyres, there's no way in hell it'll be going double that at the crank. If the dyno operator is reckoning 50% drivetrain losses he isnt fit to operate a food mixer.

Chains are very efficient... *if* theyre properly cared for. Inefficiency comes very quickly with wear and dirt.


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## Linford (25 Sep 2012)

Drago said:


> The crank figure is little more than a computer aided guess. Unelss the motor is dyno tested on a bench it is impossible to achieve an accurate crank figure. I would contend that if a Scooby is so ill it is only giving 110 at the tyres, there's no way in hell it'll be going double that at the crank. If the dyno operator is reckoning 50% drivetrain losses he isnt fit to operate a food mixer.
> 
> Chains are very efficient... *if* theyre properly cared for. Inefficiency comes very quickly with wear and dirt.


 
The car following it onto the rollers was a heavily modified skyline 565bhp at the crank, and 465 at the wheels - it was a subaru day, and it was one of many impreza's run then which were modified.
Other Subaru's were pushing out more, but that was a measured output on the rollers, and the car was gas analysed at the time through he run The crank figure quotes was the standard factory figure, so probably a bit down on this as the car was then about 5 years old. Still it was a 4wd system on a 4wd rolling road so any losses should have been calulated in or out of the numbers,and one would expect the rolling road manufacturer to have done some calibration tests and given tabless to work from for different types of drivetrains.

Either way, drivetrain drag is going to be a known constant from vehicle to vehicle, and one would expect this data to be released by the manufacturers.

On motorbikes, the drivetrain with the least loss is a chain without O'rings which are only used by the race teams.


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## byegad (25 Sep 2012)

I've heard good reports from committed cyclists about belt drive. The latest offerings seem to equate to a bad dérailleur in efficiency, so pretty good. Sadly if you then bolt on a hub gear, and some of their efficiency figures are not so good, you end up with a less efficient drive-train than a decent dérailleur system. The ease of maintenance and lack of oily parts makes up for this on a town bike built for comfort rather than speed.


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## Ian H (25 Sep 2012)

Decent 1/8th chain and a hub geared wheel with no dish would appear to be your best bet. But also look at your riding technique. Can you teach yourself to pedal lower gears more smoothly?


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## Norm (25 Sep 2012)

Drago said:


> The crank figure is little more than a computer aided guess. Unelss the motor is dyno tested on a bench it is impossible to achieve an accurate crank figure.


Not necessarily. Some (my local shop uses a Fuchs dyno) can measure the drive train losses after calculating the rear wheel figure to work out the difference between the crank and the tyre.

I'd love to get a Trek Soho but they were dropped in 2011, IIRC, although I understand that there might be a replacement in the 2013 model line up.


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## mickle (25 Sep 2012)

Linford said:


> Can only make a comparison with motorbikes and cars for the efficiency of the vehicles
> 
> I had my old m/bike (ZX6R - 600cc chain drive supersports) was run up on the dyno when I first got it about 10 years ago, and it was producing 99.7BHP at the back wheel, and about 112bhp at the crank.
> 
> ...


That is the most interesting post i've ever seen you write!


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## Linford (25 Sep 2012)

mickle said:


> That is the most interesting post i've ever seen you write!


 
There is more than one string to my bow mickle


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