adlai

Like instead of having to deal with expensive belts and sprockets, if you enclosed a single speed drivetrain with a tight-fitting and sealed enclosure, you would get most of the benefits of a belt without the expense of the belt components including the frame.

It seems to me that most of the enclosures were removed because they were too bulky but it should be possible to engineer an enclosure that is tighter fitted.

base2 

You mean something like this?


Whose to say you can't put a belt in a chain case? I would if I had the opportunity. But that's just me being me.

I think the reason chain cases are out of favor in many places, (we know who we are) is likely down to the number of derailleur drive trains in non-utility cycling so vastly swamps the market that most people are scarcely aware IGH drivetrains exist. Then add to that the extra added production cost of said case & the fitment issues concerning flat tires and what not...A Utility bike with a chain case and IGH is probably a tough sell in a market that has never seen a utility bicycle. It screams low performance and unfamiliar in a world obsessed by performance and visible, easily understood, exposed drivetrains.

The market in recreational cycling dominated places tends toward the most enthusiastic, knowledgeable and well funded buyer. The Venn diagram overlap that also includes the Utility cyclist is pretty slim. Most likely that buyer would be the enthusiast interested in novelty of an IGH & the idea of utility moreso than the day to day practice. Belts fill this niche buyer nicely. ("Gravel-Packing, Yay!" )

Elsewhere, where cycling is a utilitarian function of daily life are unlikely to see the cost/benefit over existing oil bath chain norms. A stolen €75 omafiets is unlikely to cause heartache. My guess is the cost/benefit of a belt system probably just doesn't pencil out for this buyer.

A genuine innovation tends to see widespread adoption in a short amount of time.

79pmooney

Yup. This has been known for many years. Our love on derailleurs, weight obsession and marketing plus manufacturers' love of reduced costs between conception and the sales floor means those enclosures disappeared years ago. Common knowledge in mechanical engineering that you can make chains smaller, lighter and much longer lasting if you run them in a clean environment. That the old 1/8th' by 1/2" chain on old single speeds is the appropriate size to run in crap conditions.

veganbikes

Except not. The benefits of the belt are they take a long time to wear out and are pretty maintenance free regardless of conditions. A chain in a case is a chain in a case so it sees a little less of spray but it makes it harder to clean and lubricate and replace. Some covers are probably easier and some are a huge pain in the ass plus if you have a flat it is easier to deal with a belt than a chain and full chain case. But also the chain weighs a lot and then you are adding a full chain case which is adding even more weight a belt weighs very little.

A belt drive system is pretty cheap. If I can get say 40000kms per belt and probably longer in belt ring and sprocket (potentially almost infinite) I am spending a bit more initially but saving a lot long term and also again no maintenance at all as in no lubrication or cleaning needed (unless it gets really muddy but you would be cleaning the bike anyway).

Certainly yes a chain in a chain case is better than a fully exposed chain but compared to a belt I don't think they would win except maybe in initial cost.

slow rollin

Maybe for mid drive e-bikes you could run a wet sump chain case as a cheaper alternative to belt drive. Biggest con would be weight which is why belt drive is king. I like the look of enclosed chain bikes and could appreciate my calf not getting gunky from oil(or just use chain wax).

PeteHski

You might as well have just stopped right there. It simply isn’t practical to house a complete derailleur drivetrain in a lightweight sealed casing.

Being fully exposed to the elements is definitely the main issue with chain drives, but fortunately it is reasonably manageable.

tcs

Prototype enclosed derailleur drivetrain by Sturmey-Archer for the Gazelle Company:

tcs

Hebie Chainglider 350:

https://www.hebie.de/en/protection/c...ainglider/350/

icemilkcoffee 

That is the difficulty. It has to form a seal with the hub. Once you do that, then wheel removal will be pretty difficult.

jfouellette

It depends a lot on the user scenario. For commuting and urban use. Having chain grease soil the bottom of your pants is not fun. Enclosed chain guards can be a bigger benefit than the unlikely flat repair event which would result in your hands full of black grease.

DangerousDanR

The wheel removal problem was solved many years ago in the motorcycle world. I had a shaft drive Moto Guzzi where the rear wheel had slots that the drive mechanism fit into. Remove the through bolt and the now loose spacer. The wheel came out. A very simple design. Totally practical for a winter commuter. Probably too heavy for a sport bike when compared to an open chain drive derailleur system.

Rick_D

Agree. Belt might have a bigger up-front cost (but, we're also in an age of $80 chains) counterbalanced by vast lifespans of basically no stretching, no maintenance and the lovely silent ride. Mine has about 20k miles on the original belt and sprockets.

Pratt

Well, an enclosed chain would not cost as much as a belt drive, it wouldn't need a break in the seat stay, it would probably only last as long as the rest of the bike. There are probably other disadvantages that I just can't think of right now.

50PlusCycling

There are a lot of old bikes here in Japan, dating from the prewar years which have enclosed chains, and they are still running. The climate here runs from hot and humid to cold and dry, with lots of rain and snow, and these old bikes keep going. There were many of these bikes around the Tsukiji market in Tokyo, where they were used basically as small trucks (as the area is too tight for actual trucks), and they keep going and going. They are still common enough that you can easily find and buy one, I had one which used to be owned by the Post Office, getting to the chain was hard, there was an access point for the oil, but despite decades of use hauling mail and packages, the original driveline was in remarkable shape.

Smaug1

1. A belt weighs a lot less than a chain and has no pivot points to keep lubricated. (even if they are not dirty from outside, the oil wears out a lot faster than a carbon belt does)
2. If a chaincase were provided (as shown in the second post) that is more weight AGAIN.
3. If a belt drive is used, the chain case is completely unnecessary.

The main thing is that a clean, well-maintained chain/sprocket derailleur drive is more efficient than an IGH or Pinion gearbox.

Efficiency varies by make, model and gear ratio, but here is a chart I found recently.



My Priority Apollo 11 has the Afline 11, which we can see is between about 87 and 94% efficiency, where single speed is about 97% efficiency. I guess derailleur gears would be at 97% or pretty close to it as long as the chain line is pretty straight.

Belt drive + IGH is for low maintenance, not high performance. That bike is my slow gravel bike.

Maelochs

After many, many years as a car-free commuter, I can say that I got a lot more flats when riding every day in an urban/suburban environment, and riding pretty much daily in high-traffic commercial areas (where people shop and work.)

Also ... if a rider is not smart enough to somehow deal with long pants-legs ... maybe best s/he stay home. There have been numerous commercial and also home-made solutions. A simple wrap of any type not only guards against grease, it limits flapping int he wind. QAs far as getting greasy changing flats, I recommend nitrile gloves or their equivalent---or waxing one's chain, or just being really careful. Also, I always brought a rag just to to do clean-up in case of the need to repair. I also have a small tube of hand-sanitizer.Even if I have to do major surgery to change a tire, I could get clean before riding on.

None of the issues you mention are really issues.

Maelochs

As for chain-case bikes ... I am sure one could be built which could last a long time ... (Flying Pigeon bikes survive hard using in Beijing (not nearly so much as a couple decades ago) and if all you want to do is get form here to there .... okay. Go with an inch-wide chain. Why not mount solid tires as well ... no flats, ever.

Maybe those old Japanese bikes have lasted without maintenance for 75 years ... but I doubt it. I am sorry, but I don't see a roller chain lasting seven decades without maintenance. Even if all the rides were under a mile, grease gets old and metal wears. A chain case doesn't keep out time. let me know about the actual time between chain swaps on those old bikes and we can talk further. (I mean, most of us have picked up old bikes, even if they have been garaged for a decade or more, with rusted, seized chains ... tell me about these magic Japanese chains .... )

However, if you want a smooth-running, quiet bike which transfers as much of your physical energy into motion down the road, a sealed chain with an IGH hub is Not ideal. A chain with IGH is far superior. Anyone who was not fixated on preserving tradition of who was actually looking for the most efficient, effective solution (say, if I was buying bikes for a bike-delivery business) the superiority of a belt/IGH screams out. Clean, lower maintenance, simpler, lighter, more reliable. If what is needed is the best Bike---and the benefit of the bike is that it is the most efficient hu8man-powered transport device, and in some situations (inner cities, dense commercial districts) is probably overall better on energy/mile. And if it was a business, much, much better on cost/mile.

I don't care much, frankly, because i am fine with chains, and my commuting/utility riding days are behind me---but I can see facts. if I wanted a bike for an urban/suburban environment, daily use, low maintenance, reliable .... belt/IGH checks all the boxes.

jfouellette

I agree, belt and IGH is a hard to beat solution. I have three bikes with IGH. One of them I m thinking of converting to belt drive but this $$$.

terrymorse 

If longevity is the important feature, and you're tasked with choosing belt or chain drive, there is an example in the world: internal combustion engines.

An IC engine uses either a timing belt or a timing chain, and reportedly a timing chain in a properly maintained engine can last the life of that engine. A timing belt, not so much.

PeteHski

As we know from experience, chain life on a bicycle is quite limited due to stretch. A cleaner, enclosed drivetrain would almost certainly extend chain life, but it would still be unlikely to last forever unless you made it heavier. So the chain would still end up being a service item.

I don’t know how long belts last on bike drivetrains, but I would guess that they last considerably longer than chains in this particular application.

downtube42

I'm not sure I'll go back to a belt, after having sold my Priority Eight. It was low maintenance in terms of lubrication, but getting belt tension right after wheel removal was rather fiddly.

Maelochs

Not sure where you heard that ... timing chains can stretch just like any chain. Maybe the chain will last 250,000 .... or maybe it won't and all your valves will slam into the piston heads when the chain snaps .....

I did a little research and this is representative---and apparently, a timing chain might last 250,000. (https://www.carsome.my/news/item/rep...ing-belt-chain)

Of course, that is a short chain in a clean environment --- cleaner than an enclosed bike chain? Usually double-row too---after all, the chain is Designed to run in ICE operating conditions, and to be long-lasting .... so I would say, a lot stronger than a bike chain. Also ... in both cases regular maintenance will lenghten chain life. Seventy-five years out of a bike chain, though? I would think just rust from condensation would be an issue ... but I am not an expert in the specifics.

Rick

Belts are the best but most BD bikes don't have the range of gears to make people happy. My bicycle is as dependable as my car. A freshley oiled chain or waxed chain on a single speed or internally geared bicyle is more efficnent than a belt driven bicycle. Add some road crud and the efficency goes away. Alee at cyclingabout broke a belt at around 20,000 miles. This was from heavy use but not abused. The Duzor abused and broke a belt really quick. A belt drive bicycle with a wide gear range like the Rohloff or Pinion is going to weigh more. It is more expensive to produce belt drive bicycles with a wide range than chain driven bicycles. The belt is not the expensive part considering how long it lasts. If i had the money my next bicycle would be another belt drive with a Rohloff. It would bee a Brompton Rohloff.

terrymorse 

I heard that from Toyota:

"If your vehicle is equipped with a timing chain rather than a timing belt, there is no prescribed replacement interval."

I recently had the timing belt replaced on my Toyota Highlander, per the schedule maintenance (90k miles). Mrs tm's Prius has a timing chain, reportedly good for the life of the vehicle.

Maelochs

As I posted, timing chains are good for 250,000 miles, apparently. I had not known that until you mentioned it.