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[Richard230]

I don't know if this short discussion is right or not comparing the efficiency of the three different final drive systems used on motorcycles but the presenter is entertaining: 

[valnar]

Now if we could just get Regina chains for our Zero motorcycles...
https://motorbikewriter.com/italian-company-regina-make-maintenance-free-chain/

[JaimeC]

As someone who doesn't give a rat's ass about race track performance I've ALWAYS preferred drive shafts over belts OR chains.  Chains are at the BOTTOM of my list.  Why?  Because I prefer riding over fiddling with my bike in the garage, hotel parking lot, or campground.  If I can't have a drive shaft, then the belt is the next best thing.  Contrary to what a lot of people believe, a carbon/kevlar belt has far more tensile strength than a chain.  It also requires far less maintenance and lasts a helluva lot longer.  It's not unusual for a Harley Davidson to have belts lasting 50K or more.

There is only ONE valid reason for a road rider to use a chain:  They plan on racing and want to be able to change gearing easily for whichever track they're on.  That is really the only advantage a chain has over a belt.

Chains are also preferred over belts if you spend a lot of time offroad... but since I don't plan on entering the Baja 1000 or the Dakar Rally I'd STILL stick with a shaft under that situation too.

[princec]

I've always preferred belts too (I've own many many examples of all three types of final drive!). I just hate chain lube.
Also as I understand it ... belts actually become more efficient at speed compared to chains.
What's really sold me though is watching Hans' video of how to change the SRF belt - it's just sooo simple. Screw, screw, loosen, loop, loop, tighten, screw, done.

Cas

[ultratoad]

I found the final drive video to be highly factual....  I am interested in the new Regina chains as well....  They certainly will not be maintenance free however....  They will have to be cleaned just like current chains to keep the wearing grunge/abrasives off of the chain rollers and sprocket teeth....  The worst part of chain maintenance, spraying on a little lube was always easy....  I have had all of these drive systems....  I still prefer belt drive on street bikes for all around happiness !!!!

[JaimeC]

I've always preferred belts too (I've own many many examples of all three types of final drive!). I just hate chain lube.
Also as I understand it ... belts actually become more efficient at speed compared to chains.
What's really sold me though is watching Hans' video of how to change the SRF belt - it's just sooo simple. Screw, screw, loosen, loop, loop, tighten, screw, done.

Cas

You're right... a brand new chain will be more "efficient" than a brand new belt.  However over time, the belt's performance will change very very little whereas wear and tear will eventually degrade the chain to the point it is less efficient than the belt.

[Fran K]

The small size of the sprocket on my electric ktm and the chain kit for the Zero 3.6/7.2 is less efficient than what a "normal" street or touring bike would have.  Smaller sprockets for chains have worse effeciencies.  i suspect this could be worked out on a blackboard with calculus.

Another thing one might consider is that all three of these final drives is in the motorcycle world also a ratio reduction.

[karlh]

Final drives are virtually maintenance-free, unless they're poorly engineered.  And rebuilds are expensive.  I had to have my 2007 BMW final drive rebuilt for a main bearing failure at 48,000 miles.  I also remember when, some years ago, almost all the BMW riders in the Iron Butt Rally carried a spare final drive as failures were too common.

[valnar]

There is only ONE valid reason for a road rider to use a chain:  They plan on racing and want to be able to change gearing easily for whichever track they're on.  That is really the only advantage a chain has over a belt.

Well the belt on my FXS broke under 500 miles.  We'll see how this next one does.

[JaimeC]

Final drives are virtually maintenance-free, unless they're poorly engineered.  And rebuilds are expensive.  I had to have my 2007 BMW final drive rebuilt for a main bearing failure at 48,000 miles.  I also remember when, some years ago, almost all the BMW riders in the Iron Butt Rally carried a spare final drive as failures were too common.

That was the "new, improved rear wheel bearing."  I remember it well.  My 1999 K1200LT has the older design.  The shaft is original.  The first rear wheel bearing failed at 40,000 miles but as it was less than three years old AND a LOT of them were failing at the time, BMW replaced it at no cost despite it being out of warranty.  The second one started to fail at 180,000 miles.  140,000 miles on a rear wheel bearing is "acceptable" to me.  50,000 miles on that replacement bearing and so far, so good.

But the drive shaft has NEVER been replaced.  One unfortunate issue with it has to do with the fact that it is a dry clutch, so periodically the input splines do have to be cleaned and regreased.  BMW used to recommend that service every two years.  They use a harder alloy now and it only has to be done when shifting starts to get difficult.  In 22 years I think I've had it done five or six times.  That's not a problem on bikes with a wet clutch though.

[Richard230]

My 1991 BMW K100RS blew up its forward U-joint at 48K miles and took out the right swing arm bearing, along with eating up the inside of the shaft drive housing. Guess what? My dealer said that BMWNA had never heard of that happening before.    The parts cost $1200 at the time and had to be airlifted from Germany as they said that there were no replacement parts in NA. I wonder why?    Then I started hearing that was not an unusual failure. For at least the next 20 years, BMW followed that up with more shaft drive designs and more failures. Hopefully, they have finally solved their problems with the latest R-bike designs. 

It is interesting to note that BMW has completely given up on belt drives, after using them for about 15 years on their 650-800cc models. Now it seems like all of the new models (except the boxers) are running chains. My guess is that they are doing that to cut manufacturing costs and are not getting a whole lot of feedback from their customers demanding something other than chain drive. 

[JaimeC]

Not just the boxers.  The IL6 K1600s still sport shaft drives.  They don't make the IL4 K bikes anymore.  Damn shame.

[Eicas]

Over the years I have had all three types of drives. 

For street use I prefer belt drive.  My 08 Buell XB12Ss belt never needed any attention from 2008 to 2021 aside from a visual inspection every 3,000 miles when I did an oil change.  Down side is that belts can be damaged if not properly protected or used off-road.  Also changing gear ratios is expensive if even possible.

My old '92 Suzuki 1100F Katana was hard on chains, in spite of much cleaning, oiling, and adjustment as per manual I went through several chains and sprockets over the years.  Maybe it was under spec'd?  On the other hand my warmed over 2010 Triumph Thruxton 800 chain is still good in 2021 with just an occasional clean and lube and rarely needs a chain adjustment done during oil changes.

I have had 3 BMW bikes, 2 airheads and one "K" bike.  All require regular oil servicing of the shaft drive and occasional spline inspections and grease.  If they break or wear out, it gets expensive and can not be fixed on the side of the road like a chain or belt.

So my take is for all around street use on a stock bike belt drive is the winner.  For off road or racing the chain is best.  Chain also works well for lower powered bikes like my Thruxton at around 70 HP or less.

For heavy duty touring I would give the nod to shaft drive but being aware that regular inspections and oil changes are crucial and be prepared for the odd but expensive repair cost.

[MrMogensen]

After I installed a Scottoiler auto lubrication system it's been quite easy with chain maintenance. The leftover oil that in between squirt a little on the rear wheel is so easy to wipe away. I will never again use ordinary chain lubrication. Any dirt that tried to stick onto the chain will get thrown away. Yes it's a bit messy but not more than most regular non-stick chainlubes... and far easier to just wipe away.