Why a chain?
 

I am between bikes right now, and considering what I want for these Horizon types of rides from the USA into Mexico, SA, and who knows where. I have read many answers to the question of which bike, but my question is WHY a bike with a chain drive? I have always been a shaft-guy, because of my type of highway touring/cruising in the US, they have always been much less maintenance and general dinking around with adjustments. So, my question is why are so many recommendations for bikes with chain drive? Are the out-of-USA roads so bad? The shafts not strong enough?....???

SHAFTS:

1- Overall bike weight - Well because light bikes are inherently superior on bad roads. There is no such thing as a light shaft drive bike.

2- Unsprung weight - Having been on a ride last year when one of the guys had an old airhead, which has a relatively light shaft drive unit compared to modern shaft drives, his back wheel was unable to follow the terrain properly on rough roads, even with cutting edge suspension (the same suspension I had on a chain drive bike), because of the enormous unsprung weight of the shaft drive. - i.e poorer suspension performance and more limited suspension travel over crummy roads and off road.

3- Very difficult to repair / replace .... While they are less maintenance, the reality is if you follow a lot of reports on here, as I do, you often see guys stranded in Kazakhstan, or Mongolia or Africa, or wherever for weeks with a broken shaft or final drive, and there is no way to fix it short of shipping out a new part. A chain is a simple, light, common replaceable part that you find in bike shops the world over. They are not a lot of maintenance at all, they just need to be changed every 10,000 miles or so depending on how and where you ride.

4- They are not bulletproof ... You may end up like this guy:

http://tiffanystravels.smugmug.com/O...200%20gs-M.jpg

5- They are less efficient at transmitting power from the engine to the back wheel

6- They are more expensive to design and produce

7- They do not allow you to change drive ratios as your needs, load, terrain, road conditions etc changes. In contrast, there is a huge variety of possible final drive ratios on chain drive bikes by changing the front and rear sprocket sizes. Changing ratios is quick, easy and cheap on chain drive bikes - that's very useful when part of your trip is on western motorways and other parts are on dirt tracks in steamy Bolivian jungles.

At the end of the day there is nothing wrong with the concept of shaft drives. If they suit your application then they suit your application. If you are someone who likes shaft drives, by all means use shaft drives.

But from a rational perspective, for an adventuring application, there are more reasons not to choose them than there are to choose them.

A chain is 2 minutes a day, a shaft is tens of minutes every few thousand miles and hours maybe three times in the bikes life.

Modern chains never snap they wear, some shaft designs are bullet proof others not.

You can buy industrial chain anywhere to get you going, splined shafts come from Germany, I don't think Moto Guzzi ever sold one, so goodness knows how long it'd take to find the right bit in their stores.

There is nothing in it. Pick your bike based on overall performance not some niggling technical detail. Some chains (eg BMW F650 single) were as underspecified as some shafts. Others go on for ever (MZ enclosed chain 100000 miles and it's industrial with a clip not rivetted O-ring).

Andy

Chain Drive:
Very efficient
Simple
Cheap
Very easy to change ratios

Shaft Drive
Less daily maintenance

In that case, there is a wide-ranging discussion in this thread:-
http://www.horizonsunlimited.com/hub...ft-drive-32357

In my opinion this would be the best solution for an adventure bike. Too bad the manufacturers apparently don´t see it that way.

People have been going on about the shortcomings of exposed chains ever since I started biking back when dinosaurs roamed the land. In the letters pages of ancient mags like Motorcycle Sport every month there would usually be someone bleating about how their BSA or something wore out a chain in 500 miles and why can't manufacturers enclose them. 50 yrs on nothing has changed except chains have become a bit more hi-tech.

Instead of enclosure all sorts of aftermarket lash ups like chain oilers have appeared and appear to be commercially successful. The occasional attempts to produce an aftermarket chaincase have all sunk without trace though (Peter Furlong anyone?). I can understand why; with the possible exception of MZ's efforts they all look as ugly as sin. A pity in some respects as they do work - my 1976 Suzuki has one and it's still running on the hardly worn original chain. OK, it's only a 125 but the chain is hardly any bigger than those fitted to bicycles and back it in the winter it survived 2000 miles of salt laden autobahn without needing oiling or adjusting.

I've had the chain snap 3 times on my KTM 690 in 15000 miles and I've had one replacement shaft on my R100GS in 50000 miles.

If I was setting off on a long trip on the airhead I would fit a new or refurbished shaft and thouroughly check the gearbox and final drive as part of the preparation. I would then be confident of at least 25000 miles trouble and maintenance free (and this is one of the less robust shaft drives). For me in normal use the unsprung weight and limited travel is not an issue. At travelling speeds (as opposed to racing speeds) the rear suspension performs well off road.

Chain drive does have a number of benefits and I would favour it for day to day off road riding as long as you carry all the stuff to get you home in the event of a failure.

enclosed chains
 

hi I had a Yamaha tr1 fully enclosed chain case on my Yamaha sr500 ( I tried a peter furlong case too complicated lots of parts was a hassle in the front garden let alone at the road side) ,the tr1 case took a lot of hours to make it fit but what a difference ,I was using standard heavy duty chains ( before x-ring chains) which I would get about 12,000 miles with lots of oiling and adjusting ,I then put a new standard heavy duty chain in when I put the chain case on and got 36,000 miles with hardly any adjusting and just take the chain off clean and boil in chain oil maybe twice a year (I was doing around 12,000 miles a year then) the rear wheel would stay cleaner as well ,it always gets me how in the bike world we seem to treat the effects and not the cause, example in the car world cv joints ,open to the elements so clean and regrease or cover up with a boot to stop the grease being washed out and contaminated with dirt,treat cause and effect ,bike world cover up chain to keep it cleaner with less maintenance or keep adding new (special expensive )oil to replace the oil washed off, yes that sounds about right,treat effect not cause , it used to be the same with helmets linings getting dirty ,take out and wash ,so cant take out linings so buy special expensive cleaners to clean the linings again treating the effects and not the cause problem although this seems to be getting better? as some helmets the lining is removable , there I have had my rant steve

And there you have one more advantage of a chain drive, as opposed to a shaft drive: if you want, it´s very easy to carry a spare chain & sprockets (=all secondary drive parts) with you. That should make you pretty self-sufficient, no matter where you go, and you don´t need to be much of a mechanic to change them all in the bushes. And even if you don´t want to carry them all, finding replacement chains is also possible almost anywhere.

It comes down to how easy you can fix a problem if anything happens. Chains are easier to deal with.

I've had two R12GS's (normal and a GSA), the first one blew the output seal in the south of Spain.. and the other one blew the final drive bearing 2 weeks after I got (2nd hand). I dumped the R12GSA with 90k, as I got more and more concerned that the final drive would pack in....


Casper

Shafts suck.... Beemer shafts REALLY suck.

And it's not just the shaft that is a headache, it's all the extra gubbins that goes with them..

Try changing your final drive bearing in a workshop in Mongolia or finding someone who can swap out your RWD oil seal in Mexico when it inevitably starts leaking..

They're great for long distance, non-maintenance riding but out in the wilds, simple is ALWAYS better.

Chain and sprockets are simple, easy, and everyone understands them...

Something is wrong with your KTM. Check the runout of both sprockets/output shaft/rear axle. Also check chain alignment throughout the range of rear suspension travel.

The only snapped chain I have ever seen in person was on a KTM. The dealer had changed it about 500 miles before, so maybe they are a PITA to fit correctly?

F650 chains fail very quickly once they start to go. It's because BMW or Aprillia took a chain meant for a 250 twin and used it on a 650 single.

The difference with the MZ enclosed chain and a lot of the others is that it was designed on, not bodged together afterwards. If you don't get the tubes in the engine case grooves it fails. Assemble correctly once, leave it alone and it'll work for years. I'm surprised no one has designed a bike specific add on though. Modern adhesives should make it possible at add something like the MZ grooves to the back of any case.

Andy

That's interesting as one of the guys I met in southern Germany on this year's Elephant rally was stranded with a snapped chain on his F650. One of the side plates had snapped, the chain had opened up, jumped the front sprocket and taken out a chunk of engine casing. We wondered whether battery acid vapour was responsible as there didn't seem to be any significant wear on the rest of the chain or the sprockets but the failed side plate had a kind of fault line break in it.

The chain looked to be the same size as those on my XR600 and CCM600 so I wouldn't have thought it underspecced. It certainly hadn't been ridden hard.