Chain vs Shaft

[Huambo81a]

`m not technically minded, but something occurred to me.

Why do we have chain driven motorcycles? Apart from being cheaper, what is the advantage of a chain drive over a shaft drive? Why are there not more shaft driven motorcycles, i notice the BMW HP2 Sport is shaft driven, but thats the only desireable motorbike i can think of thats shaft driven.

Why dont we have shaft driven Hayabusas and R1's? Surely for racing it would be easier to change the wheels? The only bad thing would be that its more difficult to adjust the sprockets etc, but thats an irrelevance to a road rider like me.

Maybe those mechanically minded folks here can say?
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[colin1]

you lose power with shaft drive

also in some cases, if you accelerate hard on a shaft drive bike, it can affect the steering

a chain drive with a scottoiler is the best of both worlds
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[D O G]

Chains are shit IMO.

Dirty, require much more maintenance than a shaft, and are a consumable part.

The only benefits are lightness and efficiency. My understanding is that a chain drive is 99% efficient (sprocket to sprocket) and a shaft is only 96-7%. Doesn't seem like a lot to me.

It is annoying that there are not so many shafties kicking about other than beemers. I would love a R1200S.

I guess shafts are associated with tourers and old man's bikes - not cool for sportsbikes.

Other than race reps (where a shaft would look stupid), I don't see the point in chain drive.

[doggone]

[panrider_uk]

A chain is more efficient and lighter so a must on a sportsbike.

A shaft means no mucking about with adjustments or danger of snapping or coming off.

The other option is belt drive (the scoot's belt snapped on the way to work one day leaving me waiting for a recovery truck).

Mark
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Current bikes: Honda ST1100 Pan European. Moto Guzzi V85 TT Travel

[G]

Scooter belts are a little difference in design and function to motorbike drive belts, to be fair.

You still have to replace the shaft oil occasionally in a shaft drive.
Not only do you loose power, you add to unsprung weight, which is considered bad for various reasons.

[doggone]

I know of a few accidents to machine and rider caused by chains breaking and flailing about.
With any luck the EU will ban them soon

[panrider_uk]

[tatters]

[Cigaro]

I think belt drive is a great idea - seen a couple of Buells and Harleys with belt drive and the owners seem very happy.

Obviously they can snap, but then so can a chain. And I can see them being far lighter than a chain, and requiring less maintinence.

[panrider_uk]

[D O G]

I would be interested to know how much of a difference in weight we are talking about, since that is one thing I don't know.

I really think any efficiency point is completely moot when we're talking about 2% on 160+bhp. The K1200R is no slouch, from my experiences of them on trackdays.

[panrider_uk]

The shaft itself isn't too heavy - its the housing/gearing that adds the weight.

My bike still does 0-60 in 4ish secs and around 140mph which is more than quick enough for me.

Mark.
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Current bikes: Honda ST1100 Pan European. Moto Guzzi V85 TT Travel

[G]

[panrider_uk]

Get a shaft and you don't have to fit aftermarket bits

Mark
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Current bikes: Honda ST1100 Pan European. Moto Guzzi V85 TT Travel

[G]

Bendy's new tourer-toy came with one fitted .

[D O G]

Or have to regularly clean crap from your chain (neccessitating an extra aftermarket part - being a paddock stand if you don't have a centre stand), and bodywork. Nasty.

Back on the weight thing, still haven't really got to the bottom of it. If you took all the parts of a shaft vs a chain drive, what would be the weight difference - 5kgs vs 3?

Anyone know?

[G]

Shouldn't need to clean the chain too much with a chain oiler (and don't need a paddock stand to do it), the rest is just being a tart .

Shaft drive broke on my mum's BMW; suspect it'd be more of a difference than that in total from what I remember of the weight of the bits.

[The Shaggy D.A.]

[Kickstart]

Hi

Chain is a lot more efficient (when in good condition), quite a bit lighter (and most of that is unsprung weight), cheaper and means the gearing can be changed easily.

Shaft has less required maintenance, although on some setups more than you would think (think on some bikes the UJs are service items and are not expected to last much longer than a chain, yet cost a hell of a lot more).

Belts work well. Think with efficiency they are similar to chains. Biggest problem is that they are a pain to fit (no way to easily join them) and that although they last a similar amount of time to a chain they tend to give very little warning of failure.

While a chain failing can have nasty results, the nasty results are not that common. Hate to think of the results of a snapping UJ with shaft drive.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[map]

As said above, chain is lighter so on sports bikes where every gram counts I guess a necessity.
Having said that, didn't BMW do racing once upon a time?

I guess it's also a matter of distance travelled.
Your average sports bike rider tends to do it in short bursts so maintenance can be managed. Tourer riders tend to be long distance and/or year round (maybe that's because they're shaft, cause and effect there ) so maintenance about as often as tyre changes.

IMO I wouldn't look at a touring bike without shaft. Having said that the likes of the Blackbird and Hayabusa seem to manage, although bikes of that ilk maybe need a chain to have a 'sports tourer' tag.

Also any talk of a shaft drive affecting the handling, acceleration, etc. is just twaddle. In everyday use your average rider wouldn't notice. Even taking it on a track your average rider wouldn't find a shaft any hassle.


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[Itchy]

is it BMWs that need shaft maintenance then? , in that in 45K on the NTV all I've done is changed the shaft oil once,

Keith's the keith I know's GT550 he changed the oil every 35K and that had done close to 315K..

Also CX500s I've seen like Gaz's at Regents had done well over 110K and hadn't needed to be changed...
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[Charlie]

I think belts are a lot better idea, but I think the only reason you don't see many Japanese bikes with belt drives is because they have invested too much money in chain technology and don't want to loose their investment.
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[Kickstart]

Hi

From memory one that had it apply was some late 1990s Guzzis. Think it was a 15k service item and rather more expensive than a chain and sprocket kit.

With BMWs I think the biggest problem has been wear in the bevel gears.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Wafer_Thin_Ham]

I think Bike magazine had a article on the pros and cons of chains, shafties, and belts in the mag this month actually, so if you're in WHSmiths.
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