5 ms·

I'll tell ya what I see: no rollers. Pins rubbing (wearing) both sides of the tooth. Including the back side, which will never exert any forward longitudinal fo

I'll tell ya what I see: no rollers. Pins rubbing (wearing) both sides of the tooth. Including the back side, which will never exert any forward longitudinal force on a chain unless it's made of magnets. I also see a highly suspect FEA diagram on the right, where teeth not even engaged still show non-zero stresses (lighter blue, not the darkest blue), indicating that the color/stress scale has been changed compared to the baseline on the left. So it's not an honest comparison. Add to that the fact that this is a 'better mousetrap' that requires you to first replace all the mice in the house, and I guess I'm a bit (to use one of Bike Snob NYC's favorite words) nonplussed.

ComputerGuru 6y ago
> I guess I'm a bit (to use one of Bike Snob NYC's favorite words) nonplussed. JK Rowling taught me that nonplussed is apparently a part of the daily vernacular in the UK.
- rdiddly 6y ago
  I like how it can mean either 'confused' or 'unimpressed' which in certain situations can almost be opposites of each other. But both apply to me with this chain system!
  - switch007 6y ago
    I (a Brit) was confused by the apparent use to mean "unimpressed" but I stumbled upon this: > Note: The use of nonplussed to mean "unimpressed" is an Americanism that has become increasingly common in recent decades and now appears frequently in published writing. It apparently arose from confusion over the meaning of nonplussed in ambiguous contexts, and it continues to be widely regarded as an error. https://www.merriam-webster.com/dictionary/nonplussed https://www.merriam-webster.com/dictionary/nonplussed
    - pbhjpbhj 6y ago
      Well I (a Brit) have only ever understood it to mean 'not sufficiently impressed to know what to say'; in a sort of bemusement or indecision as to one's reaction. A sort of confusion as to how unimpressed one is. The Collins dictionary I have to hand doesn't capture that nuance though. I actively try to avoid USAmericanisms, except for "y'all". Go figure ;o) [That last phrase is a USAmericanism, used for amusing intent.]
      - HelloMcFly 6y ago
        Y'all fills a hole in the English language that is not suitably filled by any other single word! It's a great word!
  - jacobolus 6y ago
    Nonplussed means “so confused that you are completely paralyzed”. Think deer stopped in headlights. Rough synonyms: confounded, flummoxed, bewildered, perplexed, stunned, shocked, dumbfounded, flabbergasted, thunderstruck. Using nonplussed to mean “unimpressed” or “apathetic” will leave listeners both unimpressed and confused.
    - raverbashing 6y ago
      > NOTE: The use of nonplussed to mean "unimpressed" is an Americanism that has become increasingly common in recent decades and now appears frequently in published writing. It apparently arose from confusion over the meaning of nonplussed in ambiguous contexts, and it continues to be widely regarded as an error. https://www.merriam-webster.com/dictionary/nonplussed https://www.merriam-webster.com/dictionary/nonplussed My observation: "continues to be regarded as an error" is a bit of a "that's not how linguistics work" thing
- forest_dweller 6y ago
  Not really. I've never heard it used in the the general publice. It is normally used by office manager types and by talking heads in politics.
  - filterfish 6y ago
    Granted, it's not a common but it's not uncommon.
  - Symbiote 6y ago
    My dad managed to say it about once a week, generally when describing disappointing work or behaviour from the children at his school.
pengaru 6y ago
I suspect lack of need for rollers is a primary feature. Conceptually, to me, the new interior bits serve as a sort of individual tooth holder that is free to rotate with the tooth as the tooth orbits the axle. So there's not much friction at the tooth:holder junction as the sprocket turns. That friction is now occurring at the narrower intersection of a hinged tooth holder and chain link. Being a narrower hinge joint, just the length of a chain link's thickness, it has less surface area for friction, and less room for debris ingress etc. Conventional chains rotate a pin across the sprocket's thickness, and AIUI use a roller to try keep debris out of and lubricant within that interface to reduce friction. This contraption takes it a step further. You can actually envision the tooth holder as analogous to the roller in a conventional chain, just with less surface area at the twisting intersection. They've obsoleted the conventional roller.
to11mtm 6y ago
If this chain is truly more efficient and/or durable, I would expect them to be selling to two specific markets: - BMX: This market would be all over anything that would be an improvement in durability, and frankly a percentage would just do it for the different tooth design. - Auto: Admittedly, the site for the company that is making this new chain mentions automotive in a blog post, but I don't see anything specific to an automotive product. A more durable and efficient timing chain is something I'd expect most of the automakers to care about.
- dharmab 6y ago
  Tangent: BMW has developed a new diamond-coated chain for motorcycles which they claim requires no regular maintenance. (Motorcycle chains, which are external and near the ground, have to be cleaned and re-lubricated every 300-500 miles for maximum life.) https://www.bmwblog.com/2020/08/27/m-endurance-motorbike-chain/ https://www.bmwblog.com/2020/08/27/m-endurance-motorbike-cha...
  - calvinmorrison 6y ago
    Another point: BMW Motorrad has used driveshafts on their bikes since the 80s. In a conventional setup much like a automobile. The only real majntaining is to lube the end gear which sits in a kind of differential housing (there's no diff, but imagine how a car's driveshaft connects to the rear axle). My bike (a k75) has it and well it's pretty cool!
    - dharmab 6y ago
      That's only on the touring models, where the lower maintenance intervals justify the weight and inefficiency. The smaller off-road models like my F750GS and the performance-oriented models like the S1000R use chains for durability/repairability and efficiency.
      - bch 6y ago
        It’s every K and R bike they’ve make since the 1930s (for the R models), including touring bikes but also the GS (which perhaps is a tourer these days, granted), R Nine T (street/sport), R18 (bobber/cruiser), and R1250R roadster.
rconti 6y ago
I don't know anything about FEA, but in reading this article and thinking it through, was the first time it hit me how bad a conventional chain and sprocket is. On a brand-new set with perfect tolerances, you might be able to use many of the front side of many of the teeth, but as SOON as the chain begins to stretch (wear) even fractionally, most of the stress goes to the 'first' teeth in any given power stroke, and the same spot on the chain. I imagine if you're putting, say, 1000w through 2 teeth and 2-4 chain endplates, wear is an order of magnitude higher than if you're able to effectively transfer power through double the teeth and endplates. Likely the "pins rubbing" you mention doesn't really matter, because the wear from inserting and removing the chain as it cycles around has to be a miniscule fraction of the wear that occurs under load.
- Obi_Juan_Kenobi 6y ago
  Bike chain teeth do not have straight sides or a convolute profile. They are wedges that act as ramps for the rollers. As the chain wears, it is no longer possible for the rollers to all sit at the base of the teeth. Instead, to account for the increased pin-pin distance, they begin to ride 'up' the teeth at the point of first engagement. You can easily see this when looking at a worn cassette used with a stretched chain. The tooth profiles become sharply hooked as the roller wear works in from the 'side' of the tooth. https://pbs.twimg.com/media/EFYuxlJXYAA89-b.jpg https://pbs.twimg.com/media/EFYuxlJXYAA89-b.jpg Note that the lowest point of the profile remains at the original base of the tooth, and then is angled up. In a worn chain, the rollers engage high up, and then work their way down (under high load) until seated at the base. In the unworn condition, engagement begins at the base of the tooth where the forces are better spread over the roller. In point of fact, the forces are spread out over more teeth when worn. The first tooth engagement might begin 3mm high, then 2.5mm, then 2mm, etc. over ~6 teeth. Whereas the fresh chain might manage 2 or 3. But the wear and friction of the worn chain is much higher as you have a great deal of motion under high load as the loaded rollers creep down. The unworn chain has perhaps higher loads, but the roller is essentially seated and immobile at the base of the gear for this.
- foobar1962 6y ago
  > ..it hit me how bad a conventional chain and sprocket is. Not at all! The article claims 98% efficiency. Roller chains are used to transfer torque in bicycles and motor cycles, inside internal combustion engines to drive cam shafts... and many more applications covering a huge range of power levels and environments. Not only is it efficient, it's cheap. If that last 2% of efficiency was important (or easy to obtain) it would have been on a GP motorcycle already.
baybal2 6y ago
I'm afraid this is kind of a scam too. The solution clearly loses on weight/benefit ratio to just making a thicker chain.
- pcl 6y ago
  At the pro level, bicycles are regularly below regulation weight, and then dead weight is added to get back to spec. So, there is budget for extra weight for higher performance parts. However, the rule of thumb is to minimize rotational weight (e.g., wheels) due to the increase in rotational inertia. I wonder whether chain weight is similarly problematic.
  - aardvarkr 6y ago
    Just for argument’s sake, does rotational weight really give a performance impact? I expect it marginally improves initial acceleration but I also expect top speed is unchanged. Heavier wheels would allow you to coast for longer without needing to pedal (conservation of momentum) but besides the initial acceleration performance is mostly unchanged. Unless you’re constantly stopping and starting idk if it makes much difference. Similarly, I’d expect the chain’s weight to have a minuscule impact on acceleration but the increased efficiency sounds like it is several orders of magnitude beyond whatever trade off there is to a slightly heavier chain.
    - TylerE 6y ago
      Yes. More rotating weight = more energy expended to accelerate the wheel.
    - pcl 6y ago
      In many types of races, cyclists are pretty much constantly changing speed, so the extra inertia matters a fair bit. Often, races are won and lost in the final dash to the finish line, which is pretty much all about acceleration.
    - derbOac 6y ago
      No. https://m.youtube.com/watch?feature=youtu.be&v=0QDnUkUaQfk https://m.youtube.com/watch?feature=youtu.be&v=0QDnUkUaQfk It's interesting to look into what's actually scientifically supported in biking and other sports, and the implied effect sizes.

ComputerGuru 6y ago

> I guess I'm a bit (to use one of Bike Snob NYC's favorite words) nonplussed. JK Rowling taught me that nonplussed is apparently a part of the daily vernacular in the UK.

rdiddly 6y ago
I like how it can mean either 'confused' or 'unimpressed' which in certain situations can almost be opposites of each other. But both apply to me with this chain system!
- switch007 6y ago
  I (a Brit) was confused by the apparent use to mean "unimpressed" but I stumbled upon this: > Note: The use of nonplussed to mean "unimpressed" is an Americanism that has become increasingly common in recent decades and now appears frequently in published writing. It apparently arose from confusion over the meaning of nonplussed in ambiguous contexts, and it continues to be widely regarded as an error. https://www.merriam-webster.com/dictionary/nonplussed https://www.merriam-webster.com/dictionary/nonplussed
  - pbhjpbhj 6y ago
    Well I (a Brit) have only ever understood it to mean 'not sufficiently impressed to know what to say'; in a sort of bemusement or indecision as to one's reaction. A sort of confusion as to how unimpressed one is. The Collins dictionary I have to hand doesn't capture that nuance though. I actively try to avoid USAmericanisms, except for "y'all". Go figure ;o) [That last phrase is a USAmericanism, used for amusing intent.]
    - HelloMcFly 6y ago
      Y'all fills a hole in the English language that is not suitably filled by any other single word! It's a great word!
- jacobolus 6y ago
  Nonplussed means “so confused that you are completely paralyzed”. Think deer stopped in headlights. Rough synonyms: confounded, flummoxed, bewildered, perplexed, stunned, shocked, dumbfounded, flabbergasted, thunderstruck. Using nonplussed to mean “unimpressed” or “apathetic” will leave listeners both unimpressed and confused.
  - raverbashing 6y ago
    > NOTE: The use of nonplussed to mean "unimpressed" is an Americanism that has become increasingly common in recent decades and now appears frequently in published writing. It apparently arose from confusion over the meaning of nonplussed in ambiguous contexts, and it continues to be widely regarded as an error. https://www.merriam-webster.com/dictionary/nonplussed https://www.merriam-webster.com/dictionary/nonplussed My observation: "continues to be regarded as an error" is a bit of a "that's not how linguistics work" thing
forest_dweller 6y ago
Not really. I've never heard it used in the the general publice. It is normally used by office manager types and by talking heads in politics.
- filterfish 6y ago
  Granted, it's not a common but it's not uncommon.
- Symbiote 6y ago
  My dad managed to say it about once a week, generally when describing disappointing work or behaviour from the children at his school.

pengaru 6y ago

I suspect lack of need for rollers is a primary feature. Conceptually, to me, the new interior bits serve as a sort of individual tooth holder that is free to rotate with the tooth as the tooth orbits the axle. So there's not much friction at the tooth:holder junction as the sprocket turns. That friction is now occurring at the narrower intersection of a hinged tooth holder and chain link. Being a narrower hinge joint, just the length of a chain link's thickness, it has less surface area for friction, and less room for debris ingress etc. Conventional chains rotate a pin across the sprocket's thickness, and AIUI use a roller to try keep debris out of and lubricant within that interface to reduce friction. This contraption takes it a step further. You can actually envision the tooth holder as analogous to the roller in a conventional chain, just with less surface area at the twisting intersection. They've obsoleted the conventional roller.

to11mtm 6y ago

If this chain is truly more efficient and/or durable, I would expect them to be selling to two specific markets: - BMX: This market would be all over anything that would be an improvement in durability, and frankly a percentage would just do it for the different tooth design. - Auto: Admittedly, the site for the company that is making this new chain mentions automotive in a blog post, but I don't see anything specific to an automotive product. A more durable and efficient timing chain is something I'd expect most of the automakers to care about.

dharmab 6y ago
Tangent: BMW has developed a new diamond-coated chain for motorcycles which they claim requires no regular maintenance. (Motorcycle chains, which are external and near the ground, have to be cleaned and re-lubricated every 300-500 miles for maximum life.) https://www.bmwblog.com/2020/08/27/m-endurance-motorbike-chain/ https://www.bmwblog.com/2020/08/27/m-endurance-motorbike-cha...
- calvinmorrison 6y ago
  Another point: BMW Motorrad has used driveshafts on their bikes since the 80s. In a conventional setup much like a automobile. The only real majntaining is to lube the end gear which sits in a kind of differential housing (there's no diff, but imagine how a car's driveshaft connects to the rear axle). My bike (a k75) has it and well it's pretty cool!
  - dharmab 6y ago
    That's only on the touring models, where the lower maintenance intervals justify the weight and inefficiency. The smaller off-road models like my F750GS and the performance-oriented models like the S1000R use chains for durability/repairability and efficiency.
    - bch 6y ago
      It’s every K and R bike they’ve make since the 1930s (for the R models), including touring bikes but also the GS (which perhaps is a tourer these days, granted), R Nine T (street/sport), R18 (bobber/cruiser), and R1250R roadster.

rconti 6y ago

I don't know anything about FEA, but in reading this article and thinking it through, was the first time it hit me how bad a conventional chain and sprocket is. On a brand-new set with perfect tolerances, you might be able to use many of the front side of many of the teeth, but as SOON as the chain begins to stretch (wear) even fractionally, most of the stress goes to the 'first' teeth in any given power stroke, and the same spot on the chain. I imagine if you're putting, say, 1000w through 2 teeth and 2-4 chain endplates, wear is an order of magnitude higher than if you're able to effectively transfer power through double the teeth and endplates. Likely the "pins rubbing" you mention doesn't really matter, because the wear from inserting and removing the chain as it cycles around has to be a miniscule fraction of the wear that occurs under load.

Obi_Juan_Kenobi 6y ago
Bike chain teeth do not have straight sides or a convolute profile. They are wedges that act as ramps for the rollers. As the chain wears, it is no longer possible for the rollers to all sit at the base of the teeth. Instead, to account for the increased pin-pin distance, they begin to ride 'up' the teeth at the point of first engagement. You can easily see this when looking at a worn cassette used with a stretched chain. The tooth profiles become sharply hooked as the roller wear works in from the 'side' of the tooth. https://pbs.twimg.com/media/EFYuxlJXYAA89-b.jpg https://pbs.twimg.com/media/EFYuxlJXYAA89-b.jpg Note that the lowest point of the profile remains at the original base of the tooth, and then is angled up. In a worn chain, the rollers engage high up, and then work their way down (under high load) until seated at the base. In the unworn condition, engagement begins at the base of the tooth where the forces are better spread over the roller. In point of fact, the forces are spread out over more teeth when worn. The first tooth engagement might begin 3mm high, then 2.5mm, then 2mm, etc. over ~6 teeth. Whereas the fresh chain might manage 2 or 3. But the wear and friction of the worn chain is much higher as you have a great deal of motion under high load as the loaded rollers creep down. The unworn chain has perhaps higher loads, but the roller is essentially seated and immobile at the base of the gear for this.
foobar1962 6y ago
> ..it hit me how bad a conventional chain and sprocket is. Not at all! The article claims 98% efficiency. Roller chains are used to transfer torque in bicycles and motor cycles, inside internal combustion engines to drive cam shafts... and many more applications covering a huge range of power levels and environments. Not only is it efficient, it's cheap. If that last 2% of efficiency was important (or easy to obtain) it would have been on a GP motorcycle already.

baybal2 6y ago

I'm afraid this is kind of a scam too. The solution clearly loses on weight/benefit ratio to just making a thicker chain.

pcl 6y ago
At the pro level, bicycles are regularly below regulation weight, and then dead weight is added to get back to spec. So, there is budget for extra weight for higher performance parts. However, the rule of thumb is to minimize rotational weight (e.g., wheels) due to the increase in rotational inertia. I wonder whether chain weight is similarly problematic.
- aardvarkr 6y ago
  Just for argument’s sake, does rotational weight really give a performance impact? I expect it marginally improves initial acceleration but I also expect top speed is unchanged. Heavier wheels would allow you to coast for longer without needing to pedal (conservation of momentum) but besides the initial acceleration performance is mostly unchanged. Unless you’re constantly stopping and starting idk if it makes much difference. Similarly, I’d expect the chain’s weight to have a minuscule impact on acceleration but the increased efficiency sounds like it is several orders of magnitude beyond whatever trade off there is to a slightly heavier chain.
  - TylerE 6y ago
    Yes. More rotating weight = more energy expended to accelerate the wheel.
  - pcl 6y ago
    In many types of races, cyclists are pretty much constantly changing speed, so the extra inertia matters a fair bit. Often, races are won and lost in the final dash to the finish line, which is pretty much all about acceleration.
  - derbOac 6y ago
    No. https://m.youtube.com/watch?feature=youtu.be&v=0QDnUkUaQfk https://m.youtube.com/watch?feature=youtu.be&v=0QDnUkUaQfk It's interesting to look into what's actually scientifically supported in biking and other sports, and the implied effect sizes.