What Final Drive is Better for Motorcycles: Chain, Belt or Spiral Gears?

I have put a fair amount of miles on my chain and am very surprised that it has no lengthened much at all. I am on the 3rd set of tires with the same chain. My mates I rode with in England would have taken a link out or replaced theirs by now. I ride my 2000 CBR 600 fairly quickly, I could keep up with the fireblades and R-1's my mates had no matter how we rode (as long as we stayed below 120 mph). I did have to thrash about a bit more and hold a better line in the corners but I kept up. Perhaps it is because I am only getting >90 bhp that I dont wear out my chain as quick? I do keep it well lubed with good spray and have not wore it off riding in the wet as much as I used to in England.

I had been wondering the same as your question myself. I would think that a good belt is lighter than a chain, I have heard they last longer and do not stretch much at all, even with the torque driven Harleys. But like you , all I have seen on sport bikes is chain.

Drew

Hey Laughing Jaguar, long time no see! As an avid, like pretty much an every day rider, even in snow and bad weather (not as crazy as it sounds) my preference has been chain driven. For my higher powered bikes or keeping in some reasonalbe RPM range for cruzing, I like the ability to change gear ratios and for the reliability. I buy the best I can and am religious about lubrication. For more of a touring I don't mind the shaft drive of my older Yamaha due to the obvious less maintenance. Some of my friends with BMW 1200 series have had problems with differential problems with certain years. Yes it seems like over the years chain assemblies and their materials in their development have become so much better! Less stretch and quick break in and longer lasting. With all my driving, I go through three sets of tires and usually two sets of chains within a year time. Depending how many miles I put on with one bike. But I'm heavy on the throttle at times and with over 30 years of riding I've never lost a chain. Although in the earlier years chains sure didn't last long! Now, in fact I seem to worry more on the shaft driven bike. Watching Super Bike racing over the recent years, Isle of Man, GP, etc, I've yet to see those guys ever loose or break a chain while sailing at 200mph. I feel it's tried and true and the componants are even better today!

"Some of my friends with BMW 1200 series have had problems with differential problems with certain years."

Differential? Why would a bike have a differential? Final drive, yes (right-angle achieved through ring-&-pinion, spiral bevel, etc.), but the function of the diff. is to permit right and left wheels to turn at different speed through turns (for rear-only or front-only drive; a third one is needed for four-wheel drive but that shouldn't apply to motorcycles).

Agreed! THanks. I probably should not be posting at 1 in the morning half asleep!

The reason that chain is used on the modern safety bicycle is that, out of the drives listed, it is the most efficient.

As to which is better, well, that depends on the weighting of the criteria judged to form the measure "better".

G'day Mr Slack, why do you say, or what is a, modern safety bicycle?

, as opposed to

<...Mr...> How abstruse.

Another critical advantage is the elasticity of the drive (in case of chain). Even the best of the direct drives (gears or otherwise) will not be able to take the shocks that can be taken by chain.

Just to give an example- I have two battery operated wagons in my work shop, both are 40T capacity. One is with the axle driven through chain/sprocket (after the usual gear box). In the other the axle is direct driven through planetary.

We can make out the gearbox begging for mercy when we put a brake or there are bumps (and that is despite all the suspensions et all and a hydraulic cplg between motor and gearbox)

Ze shaft voss design for ze german BMW so zey not get ze finger poked in ze sprocket.

"Ze shaft voss design for ze german BMW so zey not get ze finger poked in ze sprocket"

Das was guud, you is a real sprinkler!

L.J.

Moto Guzzi has had very good luck with shaft drive as long as BMW.

One of the main considerations for the racing bikes is the ease of changing gear ratios. It would be a major problem to be able to change gear ratios as fast and easy on a shaft drive as you would to change one or even 2 sprockets.

I take exception to the statement that chain drive has less unsprung weight than shaft drive. It is actually lighter when you take everything into consideration.

Rich Hurd

ex MotoGuzzi rider (if you really feel like having fun, ride a lime green MotoGuzzi to a Hells Angels convention. Cody, Wyoming, Summer of 1979. I had fun)

Rick wrote:

"I take exception to the statement that chain drive has less unsprung weight than shaft drive. It is actually lighter when you take everything into consideration."

Rick didn't you just contradict yourself?

If the rear suspension is lighter, then it "has less unsprung weight".

Yes?

No ?

L.J.

My wording did not match my thoughts. You are right that I did say it wrong. I claim a senior exemption on that one.

The chain and sprockets weigh as much or more than the sprockets and chain and adjusters.

Rich

The chain and sprockets weigh as much or more than the sprockets and chain and adjusters.

Sorry... only one senior exemption allowed per day. I think it would be safe to say that the chain and sprocket and adjusters weigh more than the chain and sprockets by an amount equal to the adjusters' weight. In fact, that probably does not need to be stated.

Did you mean to make a comparison between shaft drives and chain drives? I hope you are not thinking that a shaft drive is lighter, or even close to being equal. On most shaft drive bikes, the housings and extra bearings alone weight more that the chain and sprockets. The shaft, ring and pinion, oil seals and and oil add even more weight.

I'm not sure why Aprilia chose a chain drive. It may well be simply a cost effective adaptation to the street of something proven on the race track. You know. . . the old "If it works don't fix it" syndrome.

Judging from the generous responses (and the hysterically funny one too), the driving force (Sic!) for chain drives in racing is as I stated initially. There was one I left out: the ease with which final drive ratios can be altered to suit the circuit and the rider.

To be sure, the ubiquitous chain drives we see today are not at all the chains of the 60's when Royal Enfields, a BSA or a Triumph 650 were the bench mark, rattling valves and all and the Lucas electrics which were invented by the Germans and deliberately given to the Brits before the Battle of Britain I'm sure.

"Un Sparken pluggen poofen for das Merlin in das Spitfire! Das Gud, No?"

Thanks everybody

Oh. . .and one more thing. About Isle of Mann.

That's the one truly great race event left on the planet which Bernie Ecclestone hasn't ruined!

L.J.

Wunderbar, Jawohl!

HERE HERE!!!

My opinon:

Since buying my '06 Honda Aero (750) cruiser I've become a great proponent of shaft drive, especially for long distance cruising or touring. One less worry when far from home.

However, my earlier bike driving was in the '60's and '70's when chains were a constant #$%#@$% pain in the #@%$^#@^. That said, though, I'm sure if I ever get back into off-road riding I'd want to be on a chain driven bike. I don't know that I've seen a shaft drive engineered well enough to take the severe abuse off-road riding delivers.

Belts? I just have a totally irrational dislike for them (and this said by one who used to sell the damn things at a Harley dealership).

Hooker

Consider the number of teeth carrying the load on a chain or cogged belt , versus a gear.

Chain or belt wins every time.Belts may have advantage in a relatively clean environment, but when it gets really dirty, or muddy, the chain has the advantage.

The spray lube that is commercially available for chain drives is useless in a muddy environment,like moto crosss racing.It attracts dirt and makes an abrasive grinding paste when it mixes, and wears out the sprocket and chain.I am speaking of the "spray grease" compounds that turn thick on the chain after spraying on in liquid form.

The lubrication a chain needs is in the bushings on each link.The link pins pull and rotate in an oilite bearing.Putting the lube there is what counts.External grease on the links only attracts dirt. My advice, based on over 25 years years of moto cross racing:

Use a very thin oil, (sae 20), allow it to penetrate, and wipe off excess.This has extended my sprocket and chain life tremendously in dirty evvironment.

FWIW

HTRN

"Consider the number of teeth carrying the load on a chain or cogged belt , versus a gear. Chain or belt wins every time."

I have to respectfully disagree. The gearing on my shaft driven Honda is helical. Makes for very smooth power transmission to the axle. The downside that I see/feel is in the mass of the shaft drive, in that it tends to resist changes in momentum in the mechanism much more so than in chain or belt drives.

I also seem to have more of a problem if I upshift or downshift too quickly in a hard turn. The momentum of the drive shaft tends to want to kick the rear wheel out harder than normal, worse to the left than to the right. I can only attribute this to the driveshaft as it's the only thing spinning in that axis.

I'm more than open to having my theory proven wrong.

Hooker

I'll go slightly off-topic at this point, with reference to "I also seem to have more of a problem if I upshift or downshift too quickly in a hard turn. The momentum of the drive shaft tends to want to kick the rear wheel out harder than normal, worse to the left than to the right. I can only attribute this to the driveshaft as it's the only thing spinning in that axis." My (obviously shaft-driven) BMW will do between 5 and 60 mph in first gear without using the clutch, and an equally wide range of speeds in the other 5 gears. Given that flexibility, there is no good reason for changing gear during the turn in the course of normal road riding. With the system pioneered by the British police driving school and followed by the advanced training organisations, one is expected first to select a correct speed, which is determined by the visiblity entering the turn, and to choose the correct gear at a point before the turn. This problem with shaft drives does not then exist. If you believe this is an inefficient technique, then you have not ridden, as I have, in the company of a trained policeman. Peter

Good point, and I generally agree that it is a good riding habit to select the appropriate gear before or after a turn, not in it.

I have at least one special case, though. The drive leaving my workplace is uphill and I must turn left or right out of it. If I'm at a moderate roll in first gear checking for traffic (this is a rural road so there's never very much) the rpm tells me it naturally wants me to shift into second before I complete the turn. Incidentally, the main road at this point is sloping away from me; ie, falling to my right on a left turn. This exacerbates the situation even more if I shift into second gear in the turn.

I know your BMW has a more optimum gear set than my Honda Aero but it's not hard to get into these situations of needing to do a gear change at the least opportune time, especially on unfamiliar roads.

BTW, on my Aero, I can get the back tire to skip to the left on hard braking action accompanied by aggressive down shifting even in a straight line. It seems to be the nature of this beast.

Hooker

Consider a rear sprocket with 40 teeth.Normally, about 20 teeth are engaged.The front sprocket, if it is a 14 tooth, has about 7 teeth engaged.A spiral bevel has no where near as many teeth carrying the load.Now planetary/sun gears can be a different story,with multiple smalll gears inside a large gear.This is the type they use on monster trucks for durability.

Spiral bevel drives are smooth and quiet, and very durable if kept lubed, but cannot handle large shock loads.For street use, where noise is a drawback, spiral bevel is probably best, all other factors(drivehaft inertia, etc) aside.

On the racertrack, you can't hear a chain anyway, but they take a lickin' and keep on tickin'.I have seen sprockets with teeth as sharp as razors from wear, still good enough to finish a competition.

Hi Tek wrote: "Use a very thin oil, (sae 20), allow it to penetrate, and wipe off excess.This has extended my sprocket and chain life tremendously in dirty environment."

Back in the 60's I purchased a CB450 twin, postured as as a street "scrambler" it had a chain drive.

I got an old cookie tin and prepared my own brew of Chain Bar oil, Hypoid gear oil, and generous dose of molybdenum powder.

I removed the master link, coiled the chain into a tight spiral and lowered into the brew. I then heated the mix until the oil just started to smoke. I then pulled a low vacuum using a diaphragm pump and left it alone to cool.

Afterwards I wiped the surplus from outside the chain and reinstalled it. When I sold the bike years later, the original gears and chain were still in place with 40,000 miles and the adjuster indicator had moved about 1/4 inch from where it was when new/

In theory, the heating expanded the clearances and allowed the brew to get into the innards, helped along by the vacuum.

I'd like to think it worked but I am too busy with other interests and priorities to spend the time with such a regimen today.

L. J.

Obviously you have never ridden competetively on a motocross track.I had tried every method known to man, including "cooking" as per the raceing magazines suggested.

As stated, the thin oil performed better as far as sprocket life and chain life.I could not afford to keep using anything that did not give the best results.Factory riders have deep pockets, but privateers have to work for every cent they spend on the track.

My son raced for many years competitively and did well against the factory riders, and finished 3rd overall in the 500 cc open class in Hurricane Mills Tennessee.This with a right off the show room floor Honda. All we modified was the reed valve, and set the race sag.

If he had started younger, he could have picked up a factory sponsorship, but he was in his 20's when he raced in Tennessee.Too old for factory riders.

He now rides in a seniors class (over 25 years old is a senior in motocross!)

I still drive and ride Hondas, but I don't compete.

best person to us is probably a custom bike builder or someone who has proper experience with all bikes!I have a shat drive kawasaki and i love it-but it has its draw back -1)its cause & effect are instant -therefore not as forgiving if the rider gears down to fast in a turn or when the road is wet--belt & chain over time give more and therefore are more forgiving when death is close at hand or you are a novice.but good question--What is your ride?

The only shaft bike I rode was a dressed Moto Guzzi California II for a couple of months after I re-assembled the bike and sold it for the widow of a co-worker and friend who died of a heart attack. He had the bike stripped down and was in the middle of a top-end job. It was a nice comfortable bike and the shaft drive worked well as long as you don't try to push it too hard. It was great in the sedate to mildly brisk mode. If you took it much above 6/10th's the shaft jacking and squatting became noticeable to somewhat scary. I did ride it a couple of times on the Sunday Morning Ride (late 80's, Cal Rt. 1 Marin County) but quickly went back to my 500 and 750 Interceptors.

I have to agree with the above posters about chains. Lightweight, easy to replace/re-gear, very strong, compact, but messy and a little noisy. I would get about 20,000 miles out of a typical O-ring chain with just the basic maintenance and occasional cleaning.

A couple years ago I bought a Buell Ulysses. I must say that I like the belt drive on this machine. It is light weight and quiet. It seems to hold up well to the prodigious torque from the Thunderbolt engine. With a constant force tensioner, there are no adjustments. It is very clean and Buell claims it will last the life of the bike. The only down sides are the extra width has to be considered in the design and changing the sprocket ratios would be expensive (if different parts were even available). Fortunately, I don't feel any need to re-gear this Buell anyways. Buell did extensive testing with the set-up and the videos showed the belt ingesting rocks and sticks with no damage. The tensioner will allow the path length to change depending on suspension attitude and if you manage to get a rock past the guard.

I guess it really comes down to ones personal preference. Those riding dirt bikes and carving up the canyons will stay with chain drives for their durability, ease of re-gearing, light weight, low cost, and the favorable interactions with typical motorcycle suspensions. H-D's and Buells will continue on with their belt drives that have some of the advantages of chains without the maintenance and mess factor. Shaft drives will rule the import cruiser market, touring and most of the sport tourers because they are smooth, quiet and mostly maintenance free. Those folks generally don't do things like chopping the throttle mid-corner, full-tilt and bottom a case. That's scary.

I like having choices. I remember when all bikes were the same, like the CB750 (the first UJM). They all looked the same leaving the dealer floor and the rider then made the changes to turn it into a chopper, drag bike, sport tourer, tourer, cafe racer or just left it stock (yikes!)

Cheers!

I have been riding motorcycles for over 40 years on different types of motorcycles. I have found that the best drive to be Belt drives. Chain drives require constant adjustments and causes vibration and has numeriouse moving parts that can break and cause damage and injury as well as leave you stranded. Gears also require maintance and has a vibration that transfers throughout the motorcycle. Belts require hardly any maintance and do not vibrate. However the early Harley's had a problem with misalignment and breaking. In fact in 1980 the late Phill Ross of Supermax belt drives was called into a meeting with Harley Davidson and Gates Rubber as they had learned that Supermax belt drives did not have a problem. Phil rode his dual belt shovelhead Harley from California to Elizabethtown, Kentucky, and met with Gates and Harley reps about their problems. Phil and Gates were aware of the misalignment between the engines and transmissions with the Harleys, but the H-D people had no understanding of what these problems were. He met the whole gang at the front door. They were pleasantly surprised that he had ridden all the way from California to meet with them, and with dual belts both proimary & final drive on his bike. Phil was presented a table covered with broken belts. Eighty percent of them had side wear, and the rest appeared to have been kinked due to mishandling. Phil said to the Harley rep that they would have to align these bikes if they expected to have a trouble free drive. "The H-D people answer to Phil was, and I quote, 'This is a production motorcycle and we don't have any time to line them up'". To the horror of the Gates reps, Phil's reply them was, "If you don't want to line 'em up then you should put a chain on them." And that is exactly what they did. Harley finally took Phil's advice and the new Harley's are aligned. However they still use a metal pulleys and rubber belts while Supermax uses polyurethane pulleys and No. 80 cord Kevlar belts by Gates. I have ridden with Dual Belt Drives since the mid 80's and have put on over 250,000 miles on that bike and never had a drive train problem. I believe in what Phil Ross would say "Buy your last belt drive first, buy a Supermax Belt Drive!" For more info. www.supermax.net or sleepynkat@hotmail.com Robert F. Laurin

I may be completely out of line here to say this, and I might even be wrong, too, but...

Wouldn't a belt heat up an awful lot while trying to run down the track at 200 mph?

I know the Harley guys are going to jump all over this, but there are not a lot of truly fast Harleys out there that are actually sustained run at high enough speeds to generate some internal heat in a belt. Notice that most of the sporty and/or race quality Harleys are chain driven? When Eric Buell was making the only truly race bred modern "Harley" they were all chain driven. Unfortunately he is no longer doing that..

I have had great luck with chain drives, but you have to pay attention to them and you have to do what they are asking for. A shaft drive might be less demanding to live with, but I can afford to replace a broken chain! Most importantly, over the lifetime of a bike you will never spend $1000 on chain and accessories, unless you change ratios a lot, and you will pay twice that at the showroom for the shaftie. More importantly, you don't have to carry around 3x the unsprung weight for the entire time you own the bike.

You need to experience a belt driven HD V-Rod. They run fast and long.

When I worked at a Harley dealer in Portsmouth, VA we had a lot of young European NATO officers buying them and shipping them back to Europe. They "claimed" they were beating the snot out of the best road bikes BMW could offer, both in speed and endurance.

Not sure how much I believed them, but that's what they claimed.

Hooker

Frank asked: "Wouldn't a belt heat up an awful lot while trying to run down the track at 200 mph?"

If you are referring to the heat build up due to hysteresis, then probably not.

Tires are subjected to essentially the same transfer of power and flexing and they seem to manage the situating quite well.

Assuming they are properly inflated

L.J.

In the 90's Easyrider Magazine decided to go for the land speed record on a motorcycle at Bonniville Salt Flats and to build a multi engine Harley with dual blowers on each engine. They went to Supermax for all the belts for the Blowers and the drive belts and went over 320 MPH never broke a belt. Now BUB owns the bike and again went to Phil Ross of Supermax and this time went over 326 MPH. Heat is not a problem with the Kevlar Belts but you do need air flow on all belts

Sleepy

I remember a time when there was no choice: If you rode a motorcycle, it had a chain drive.

Wow! You must be older than dirt! If we figure that you would have to have been 10 years old to sufficiently understand the details of one drive system over another, then you would have been born in 1900, to appreciate the first shaft-drive motorcycle, developed by FN in 1910. Shaft drive bicycles were around since the 1830's.

...in street machines of using spiral gear differentials

... but only in the four wheel motorcycles, in which differential action is useful.

Have there been advances in lubrication or metallurgy that I am not aware of that have given the ubiquitous chain drive a new lease on life?

Are the newer chain drives longer lived and more maintenance free than when I was younger?

Yes. The main innovation was o-rings, which seal in lubrication and which make re-lubrication more or less useless other than to keep the chain from rusting externally. O-ring chains are a huge improvement over standard chains, which have pretty much disappeared from motorcycling. Chain drives are more efficient than belt or shaft (particularly more so than shaft).

(As an aside, I put a chain drive on my generator for my plug-in hybrid trike proof of concept. I used industrial chain and sprockets for ease in selecting and changing ratios, availability, etc. Realizing that this drive runs pretty fast [and that the chain had no o-rings] I expected to have to lube the chain every hour -- but for the POC, that would be fine. [For the real deal the drive will be direct, with generator winding optimized for optimal engine speed.] I used a teflon grease which comes out of the spray can as a low visc liquid -- which i imagined would penetrate to the inside of the rollers, and which would leave at least some teflon to reduce friction. In about 20 minutes of running, the chain was entirely dry and too hot to touch -- so ,much for my guesstimate. Rather than build a proper sealed oil bath enclosure, I have switched to belt drive -- again in the interests of saving time.)

Good motorcycle shaft drive systems are the ultimate in durability, and every true touring bike should probably have one -- but only if the market for the bike strongly favors reliability and low maintenance over vehicle dynamics, and is willing to pay the substantial extra cost of sealed housings, high precision gears and splines, a few extra bearings, and lower efficiency.

Belt drives look clunky, and add a little width to the overall drive package (which in a crotch rocket could mean the the engine/transmission assembly is 1/2" wider than it otherwise would be, and that therefore the pegs are 1/4" further out than they otherwise would be, and therefore the bike cannot be leaned as much. Chain drive might have a slight advantage in lowering unsprung weight, because of the lower width of the driven sprocket (but this is cancelled by the higher weight of the chain itself -- so it would be very very close.)

Chains are easier to evaluate for wear than belts, which can fail suddenly, while still looking pretty much OK. But following scheduled maintenance is all that is required here.

The only sporty bike I can think of that has belt drive is the Buell (sadly gone ...) and it demonstrates that a belt can work very well on a sporty bike. I think the differences are very slight, belt vs chain, in almost all respects. For my proof of concept, I use a chain for final drive because it is much easier to experiment with ratios (and to this end, having a master link -- absent on most production bikes -- makes things easier, and cheaper). (The final drive chain speed around the sprocket is much lower, so fling off is not a serious issue. In a production version, I could go either way, o-ring chain belt, but will probably go with belts, in the interests of smoothness and quietness.)

Traditional shaft drives (like BMWs for many years) had an annoying tendency to "jack up" under acceleration (the pinion climbs the ring). Because shaft drive used to be applied only to motorcycles with longitudinal crankshafts, shaft drive motorcycles also use to have an annoying torque reaction to changes in flywheel speed, so if you blipped the throttle, the whole bike would lean to the side. The Honda Goldwing cured this, while retaining a longitudinal crankshaft by having counter rotating flywheels.

The jacking up effect can be eliminated with more complex linkages which decouple the torque reaction -- most, if not all BMWs now have multilink rear suspension for this reason. (Rear brakes on motorcycles are subject to similar issues, with, in the simplest set up, braking tending to compress the rear suspension. This is not necessary bad, because it tends to reduce the pitching that accompanies braking. But it also loads up the rear suspension, making the rear wheel less responsive to bumps -- so in motocross bikes it is not uncommon to see the brake reaction arm coupled to the frame, rather than to the swing arm.)

In bikes with transverse cranks, there is typically an additional set of bevel gears (which in the name of low noise and vibration are hypoid... and therefore not optimally efficient) so the overall transmission efficiency drops even more that in a longitudinal crank bike.

Ignoring primary drive, I'd estimate efficiencies at: 99% - well lubed, clean chain. 98% toothed belt. 96% longitudinal crankshaft w/ shaft. 92% transverse crank with shaft.

So... I think that chain drives will continue to be the norm for quite a while on sporty bikes. Drives shafts will continue to be seen more frequently on touring bikes, and belts will continue to be seen on cruisers -- they are a little bit smother, and little lower maintenance than a chain, and not as costly as a shaft.

Blink quoted me as saying: "I remember a time when there was no choice: If you rode a motorcycle, it had a chain drive."

And responded with: "Wow! You must be older than dirt!"

I am not older that dirt although admittedly, there are times when I feel like it. If you wish scientific accuracy however, there are parts of me that were generated during a Super Nova. Don't ask. I don't remember which one or when.

The context of that statement was the domestic North American Market as it existed in the 60's.

The only shaft drive option I had then was as single cylinder 250cc BMW which was woefully out of breath at 50 mph and likely to burst if one sustained that speed long enough. It had all the acceleration of a crippled cow and a flywheel that weighed almost as much.

One dared not add a windscreen to so anemic a machine lest one risk being outperformed by Vespas. Furthermore, one's masculinity was certain to be questioned if he showed up on a BMW at a rally populated by young men riding Triumphs or BSA's and trying to look like Marlon Brando or James Dean.

You quoted me: "...in street machines of using spiral gear differentials"

and responded with "... but only in the four wheel motorcycles, in which differential action is useful.

The term differential here, which you are apparently too young to remember, is used in it's original form which was to change the direction of rotation to something "differ"ent.

Since the addition of spider gears, the term differential has been bastardized to include any device applying power to two wheels, traveling in arcs of different radii, and thus different speeds.

"And now you know the rest of the story"

Your turn!

L.J.

"The term differential here, which you are apparently too young to remember, is used in it's original form which was to change the direction of rotation to something "differ"ent."

Extremely doubtful, IMHO; I believe that the term more closely ties to "difference" - exactly why it's needed for two wheels travelling in separate arcs.

"Since the addition of spider gears, the term differential has been bastardized to include any device applying power to two wheels, traveling in arcs of different radii, and thus different speeds."

Spider gears, per se, are not required: epicyclic or planetary differentials provide concrete examples. And all inputs, outputs, and intermediates have parallel axes... But if Wikipedia can be trusted (or the sources upon which it depends, actually), then the origin of the differential came about from two-wheeled devices pulled by humans or animals, where the path-length comparison was used to move a pointer so that it always pointed in a single direction [traditionally south]: http://en.wikipedia.org/wiki/Differential_(mechanical_device) also follow the "South-Pointing Chariot" link.

If you have any reference showing an origin for the term being as you describe it, please provide a link. Thanks!

I wrote: "The term differential here, which you are apparently too young to remember, is used in it's original form which was to change the direction of rotation to something "differ"ent."

Both Ron and Blink challenged that statement, Since I've not questioned he who told me in over 50 years, I thought, naively, that I might find Pop Drew who was my mentor when younger.

With one call I got "Are you nuts? Man he died in the 70's!"

Pop was a cam wizard with flat heads, especially those 60 cubic inch flat heads that showed up in B model fords in 32. Cams are all he did. He had a knack for regrinding cam profiles for alcohol burning race boats that ran in the regattas in the Hudson River.

After WW2, some guys started running that same engine in dirt track midgets and Pop ground the cams for them too.

He had a rear end center section out of a dirt track car, a Halibrand and showed it to me as part of my weekly lesson. It was there that the term differential became part of my lexicon. On dirt track cars both wheels turned the same. Go figure.

Smart as he was I don't think Pop had more than an 8th grade education so perhaps he was mistaken. So was I in thinking I could trust a conversation from five decades back when I was a young boy idolizing a race mechanic.

Live and learn

Don't feel bad - I had a similar experience just a couple of months back, regarding where the energy is stored in a conventional ("Kettering") ignition system. I'd always been told that the capacitor was charged while the points were open, and discharged through the coil to generate the spark for the plug. I think I even saw that description on print in supposedly technical articles. But it turns out that the energy is stored magnetically in the coil, and that the capacitor ['condenser'] is there to prevent or reduce burning of the points.

While I did NOT get that piece of misinformation from him, I was once present in a crowd when Charles Kettering, aka "Boss Kett", the inventor of that very system, spoke. The occasion was when the village of Kettering, Ohio, named for him, became a city. My brother lives there today. Yet somehow I'd never investigated the workings of one of his inventions, perhaps the one I should have understood best. Man, I spent a LOT of years understanding it all bass-ackwards!

By the way: thanks for supporting the notion of taking the pseudo-science digression up as a separate thread. It is looking quite healthy!

At the risk of again trusting my memory, didn't Boss Kett also invenmt the starter?

L.J.

Ron wrote: "By the way: thanks for supporting the notion of taking the pseudo-science digression up as a separate thread. It is looking quite healthy!"

My pleasure Ron. Wow! He rally ran with it didn't he!? I'll get over but not tonight.

Thanks for the Kudu's

LJ.

With one call I got "Are you nuts? Man he died in the 70's!"

I've had too many calls like this. If only we could at least say goodbye.

If you wish scientific accuracy however, there are parts of me that were generated during a Super Nova. Don't ask. I don't remember which one or when.

Very good point. Was it the Dalai Lama who said to the hot dog vendor, "Make me one with everything" ?

It had all the acceleration of a crippled cow and a flywheel that weighed almost as much.

At about that time, I had an Indian 30.50 Sport Scout which, although twice the displacement, performed about as well as a 250 BMW (which as you know, was even then considered a slug). (A friend had a Honda Super 90, and I think even it would give the Indian a run for the money.) (The Indian did have stump puller gearing, though, so would spin the rear wheel down the length or our gravel driveway... and it was loud, so it gave a pretty good illusion of power.) I was lucky enough to live in a community (a large development) in which the homeowners owned the roads in common (a corporation) so kids could drive around in all sorts of things, if their parents were foolish enough to let them so do. My parents were at odds re the advisability of letting a 12-year old drive a motor cycle, but my dad, perhaps wanting to relive his youth vicariously, advocated for me. What a great thing it was to be able to argue in favor of a leather jacket... for safety. My parents would not buy us kids any of this stuff, fortunately, but all three of us were entrepreneurial and made enough money among us to have a pretty good collection of bikes, lawn tractors, electric vehicles, etc that we bought as basket cases.

At the time, (early 60's) the coolest guy in town (who all of us younger kids looked up to) had a BMW 600 (or it may have been a 500) with Earls forks and sidecar. He'd give us little twerps rides and we'd spend most of the time up on two wheels, or hanging out over the edge of the sidecar, racer style. Great fun, and no one got killed. Much later, after college, I worked in a BMW/Honda/Maico/Bultaco dealership, and would love to ride the older customer bikes which had the distinctive sound and smooth power delivery of the BMW I knew as a kid.

More than any other car, Porsches (excluding of course, the SUV atrocities and the oddballs that have carried the badge) have the same ability to stimulate memories, based on the sound and feel of the engine. A few years ago, I drove a friend's Boxter, and it was crystal clear that it came from the same family as the 911's that I'd driven three decades earlier. Old friends. *

Furthermore, one's masculinity was certain to be questioned if he showed up on a BMW at a rally populated by young men riding Triumphs or BSA's and trying to look like Marlon Brando or James Dean.

I was anything but immune to such pressures, but nevertheless tended to prefer finely honed bikes over those with (what passed for) brute power. (Today, Triumph Bonneville TT special power would be considered barely adequate for a cruiser/ commuter.) It is easy to make the argument that the Marlon Brando wannabees were compensating for their inadequacies. I compensated in slightly different ways. Even in road racing, where there is little time to think such thoughts, I used to occasionally think "I must look cool as hell here, with sparks flying off the pegs and pipes." Probably, if you're having such thoughts, you're not riding well.

The term differential here, which you are apparently too young to remember, is used in it's original form which was to change the direction of rotation to something "differ"ent.

I think we are both teetering on the brink of senility -- so in my case, at least, I am not too young to remember, but too old to remember. One of the early differential gearsets was this one. While I respect your opinions (and think highly of you) I am nevertheless recommending that we convene a CR4 tribunal re your definition... which I am not buying. My hope is that you will not be badly flogged, but sometimes these things go too far, and I'm sure you will understand. If forced, I am willing to scan pages of my old mechanical computing devices text from the WWII era... but my hope is that it does not come to that.

Yours, in deadly earnest,

Blink

* This is the point where I could lapse into a rant about the destruction of real brands: VW Bugattis !!?? VW Bentleys!!?? Ford Volvos??!! Stryker Saabs!!??? (At least the new owners are from roughly the right part of the world.) Alfaferrarifiatmaseratis ??? Audi Lamborghinis!!!???

As for the original poster's question, it depends on the application.There is no "one size fits all".Each system has it's attributes that make it better for certain purposes.These same attributes make it unsuitable for other uses.

For dirt bike racing, the chain is still king, due to light weight, and durability in dirty environment.For touring bikes,belt, chain, or shaft drive is better according to the preference of the rider and the purpose of the bike.Each type has it pros and cons.

Perhaps one day, electric direct wheel drive will be possible, using a pancake motor or internal wheel-motor.(They already have conveyors with Motorols, which is a motor inside a roller ).No gearing required, a VFD for speed and torque control.

This should satisfy just about everyone.

In-the-wheel has a MAJOR drawback regarding unsprung weight.

I would like to use this discussion on my web site-I cannot believe (all good) how much has been written about this subject-good on all of you.May I use and readers digest this conversation ,with all of your permissions?

Ok by me...

Drew

OK by me. Go for it!

L.J.

Sure. You might want to give attribution to CR4.

Perhaps one day, electric direct wheel drive will be possible, using a pancake motor or internal wheel-motor.

These are actually very common in China, on motorscooters. Interesting that PML Flightlink (who have changed their name... which I can't remember) have supplied the prototype motors for a 640 hp Mini and a Ford F150 (both with one motor per wheel -- four wheel drive) have not built a motorcycle with one -- or better, two for 320 hp. With that hp, the batteries (of a size you could tuck into a motorcycle frame) would only last for a few minutes... but it would be fun while it lasted!

FYI, while your inquiry is focused on bikes, there is a fellow, Dennis Palatov in Portland OR, designing a family of track cars using chain drive in 2 and 4 wheel drive. They are very impressive. Take a look at www.dpcars.net when you have a few hours or days...