Why no N x 1 instead of 1 x N?
#76
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I would argue that having a smaller cassette might even offset some of the weight penalty, too.
We saw at least one company in recent years throw a lot of marketing budget and effort into a rear hub that mixed internal gearing with rear derailleur shifting, and call it a “front derailleur killer.”
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This.
You are overly dismissive of the work that other people did. It's weird arrogance from an internet nobody.
Note that the "we" doesn't include you because you are the one saving the day with your "great" new idea. You have no basis for accusing other people of "doing the same thing" and "stagnating" just because you came up with some idea. "Bad ideas" aren't not "doing something different" anyway. Unless, you execute the bad idea.
No, not "just" that. The problem is that you don't seem to know enough about what you are talking about and the rest of us are stuck having to read it.
You are overly dismissive of the work that other people did. It's weird arrogance from an internet nobody.
Note that the "we" doesn't include you because you are the one saving the day with your "great" new idea. You have no basis for accusing other people of "doing the same thing" and "stagnating" just because you came up with some idea. "Bad ideas" aren't not "doing something different" anyway. Unless, you execute the bad idea.
No, not "just" that. The problem is that you don't seem to know enough about what you are talking about and the rest of us are stuck having to read it.
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The way FDs currently work, it doesn't so much pull the chain off the current ring, as it does feed the chain on to the intended one. Once you have enough links engaged on the new ring (about 1/4 rotation) the FDs job is done, and the rotation of the crank finishes off the rest of the shift, using the chain tension to your advantage.
Shifting "from the bottom" would mean pulling the chain over, and lifting it off of the chainring teeth against the tension which, I imagine, would require a much more substantial and complicated mechanism than existing FD designs.
I suppose you could get around the chain tension issue by backpedaling during the shift, but the whole point of a derailleur drive train is that you can change gears without stopping pedalling
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Anyway ..... lots of very good reasons why having a dozen chain rings and only two cogs is not at all a good idea and not at all an improvement.
Also ... one way of describing the "stagnation" of a long-used machine is ..... "perfection."
If no one has come up with anything better, maybe .... we should be glad we have what we have.
Front derailleurs meet a certain definition of mechanical and engineering "elegance" in that they are ridiculously simple and ridiculously effective. To be "better" a device would have to either shift significantly more smoothly or be even smaller, lighter, and/or simpler, or all of the above.
I am willing to stipulate the electronic derailleurs might be "better" for most uses, even though they are not nearly as simple ...
Sure, there are designs for internal-gear hubs, gearboxes, etc, but in terms of what makes the best engineering sense ..... light, cheap, strong, simple, reliable, effective ..... I am sure some day scientists will concoct some sort of readily moldable, incredibly strong and flexible unobtanium compound which can be used to make bike frames with tubes the diameter of pencils and ten times the strength of steel or carbon fiber or whatever .... and I am sure someday someone will develop a miniaturized, piezo-electric fully automatic bicycle gearbox is smaller, lighter, and more reliable than modern derailleurs ... and cheap enough to be fit on Walmart bicycles. And we will all fly down to Walmart in our hovercars to buy them.
In the meantime ........
Also ... one way of describing the "stagnation" of a long-used machine is ..... "perfection."
If no one has come up with anything better, maybe .... we should be glad we have what we have.
Front derailleurs meet a certain definition of mechanical and engineering "elegance" in that they are ridiculously simple and ridiculously effective. To be "better" a device would have to either shift significantly more smoothly or be even smaller, lighter, and/or simpler, or all of the above.
I am willing to stipulate the electronic derailleurs might be "better" for most uses, even though they are not nearly as simple ...
Sure, there are designs for internal-gear hubs, gearboxes, etc, but in terms of what makes the best engineering sense ..... light, cheap, strong, simple, reliable, effective ..... I am sure some day scientists will concoct some sort of readily moldable, incredibly strong and flexible unobtanium compound which can be used to make bike frames with tubes the diameter of pencils and ten times the strength of steel or carbon fiber or whatever .... and I am sure someday someone will develop a miniaturized, piezo-electric fully automatic bicycle gearbox is smaller, lighter, and more reliable than modern derailleurs ... and cheap enough to be fit on Walmart bicycles. And we will all fly down to Walmart in our hovercars to buy them.
In the meantime ........
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There's plenty of room for improvement of gearboxes (weight, efficiency, cost, standardization). Seems like a logical place for the industry to develop THE NEXT BIG THING THAT YOU ABSOLUTELY MUST BUY.
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Let’s stop with the accusations and insulting posts. This thread is pretty good and we don’t want to close it.
#83
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On upshifts, if the front derailleur were to magically disappear before the chain is meshing with the next ring, the chain would tend to go back to doing what it was doing on the initial chainring.
But on downshifts, the chain needs to drop in height before it can mesh with the new ring. This generally won't happen until after it stops engaging with the initial ring.
I suppose you could get around the chain tension issue by backpedaling during the shift, but the whole point of a derailleur drive train is that you can change gears without stopping pedalling
Even when a derailleur doesn't require that a rider stop forward pedaling, they generally work better if pedal pressure is eased off. Various advancements have reduced this, but even modern rear shifting can sometimes get crunchy at full stomp.
Historically, there have been commercially-produced derailleurs that required backpedaling. This was especially true for racing designs from the 1930s, which often put forks or paddles on the top of the chainstay. These designs include the original Osgear Champion, the Vittoria Margherita, and Campagnolo's early derailleurs.
The earliest well-documented commercially-produced derailleur, the Gradient from the late 1890s, used a mechanism to lift the chain off of the rear cluster while changing gear. In some forms of the system, the chain-lifter was engaged by backpedaling.
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I guess not, and I presume it’s been looked at. But it appears to bring the best cases of 1x (you can use a single narrow-wide chainring, no issues with front retention) and 3x (you can have a close-spaced cassette and still have wide range)
I would argue that having a smaller cassette might even offset some of the weight penalty, too.
We saw at least one company in recent years throw a lot of marketing budget and effort into a rear hub that mixed internal gearing with rear derailleur shifting, and call it a “front derailleur killer.”
I would argue that having a smaller cassette might even offset some of the weight penalty, too.
We saw at least one company in recent years throw a lot of marketing budget and effort into a rear hub that mixed internal gearing with rear derailleur shifting, and call it a “front derailleur killer.”
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Here's an example of box-free thinking about front shifting: the Browning Transmission. Post no. 8 is from an industry guy who gives an insider's perspective.
https://www.bikeforums.net/classic-v...nsmission.html
https://www.bikeforums.net/classic-v...nsmission.html
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This is sort of a shower thoughts question, but why do bikes favor large numbers of gears in the rear vs the front? I understand why many prefer 1x setups, but when I underestimate a climb and need a bailout gear fast, shifting to a smaller chainring is just mechanically easier than having to push up to a larger rear cog.
I’m sure there’s a good reason that we have “1x”instead of “x1” and that rear clusters almost invariably outnumber chainrings, but I’m just curious what that reason is. Would the right foot hit the chain line? Something else?
I’m sure there’s a good reason that we have “1x”instead of “x1” and that rear clusters almost invariably outnumber chainrings, but I’m just curious what that reason is. Would the right foot hit the chain line? Something else?
#87
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Read the first couple of chapters of The Dancing Chain by Frank Berto to learn about the early days of derailleur gearing (1895~1935) and what was tried, what didn't work, and what lasted.
Last edited by tcs; 07-20-23 at 10:32 AM.
#88
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#89
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Here's an example of box-free thinking about front shifting: the Browning Transmission. Post no. 8 is from an industry guy who gives an insider's perspective.
https://www.bikeforums.net/classic-v...nsmission.html
https://www.bikeforums.net/classic-v...nsmission.html
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The OP isn't talking about triples.
The OP is talking about "many" gears in the front. Given that the current norm for the rear is 10 to 12, you really have to address why there aren't more than 3 used in the front.
Except for really odd examples, 3 appears to be the practical limit.
The OP is talking about "many" gears in the front. Given that the current norm for the rear is 10 to 12, you really have to address why there aren't more than 3 used in the front.
Except for really odd examples, 3 appears to be the practical limit.
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#93
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#94
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The way FDs currently work, it doesn't so much pull the chain off the current ring, as it does feed the chain on to the intended one. Once you have enough links engaged on the new ring (about 1/4 rotation) the FDs job is done, and the rotation of the crank finishes off the rest of the shift, using the chain tension to your advantage
It's both.
On upshifts, if the front derailleur were to magically disappear before the chain is meshing with the next ring, the chain would tend to go back to doing what it was doing on the initial chainring.
But on downshifts, the chain needs to drop in height before it can mesh with the new ring. This generally won't happen until after it stops engaging with the initial ring.
On upshifts, if the front derailleur were to magically disappear before the chain is meshing with the next ring, the chain would tend to go back to doing what it was doing on the initial chainring.
But on downshifts, the chain needs to drop in height before it can mesh with the new ring. This generally won't happen until after it stops engaging with the initial ring.
I should have specified that FDs don't lift or push the chain down; all they do is move it side to side; preventing it from engaging on the current ring.
The rotation of the crank is what moves the chord of the derailed chain; in a downshift, it "falls" off the side of the ring, until it encounters the top of the small ring; in an upshift, the chain side plates engage with the teeth, ramps and pins of the larger ring, lifting the chain until the rollers start engaging the teeth of the selected ring.
The chainring actually does the lifting, not the FD
Changing gears without stopping pedaling is nice, but I don't think I'd call it "the whole point." Even a derailleur that requires a large disruption to pedaling rhythm can be far less disruptive than, say, getting off the bike to move a chain to a different cog.
Even when a derailleur doesn't require that a rider stop forward pedaling, they generally work better if pedal pressure is eased off. Various advancements have reduced this, but even modern rear shifting can sometimes get crunchy at full stomp.
Historically, there have been commercially-produced derailleurs that required backpedaling. This was especially true for racing designs from the 1930s, which often put forks or paddles on the top of the chainstay. These designs include the original Osgear Champion, the Vittoria Margherita, and Campagnolo's early derailleurs.
The earliest well-documented commercially-produced derailleur, the Gradient from the late 1890s, used a mechanism to lift the chain off of the rear cluster while changing gear. In some forms of the system, the chain-lifter was engaged by backpedaling.
Even when a derailleur doesn't require that a rider stop forward pedaling, they generally work better if pedal pressure is eased off. Various advancements have reduced this, but even modern rear shifting can sometimes get crunchy at full stomp.
Historically, there have been commercially-produced derailleurs that required backpedaling. This was especially true for racing designs from the 1930s, which often put forks or paddles on the top of the chainstay. These designs include the original Osgear Champion, the Vittoria Margherita, and Campagnolo's early derailleurs.
The earliest well-documented commercially-produced derailleur, the Gradient from the late 1890s, used a mechanism to lift the chain off of the rear cluster while changing gear. In some forms of the system, the chain-lifter was engaged by backpedaling.
The movement of a couple of fingers and a half-stroke of soft pedaling should allow almost anyone to successfully complete a gear shift on a halfway -in-tune bicycle. It both higher performance, and easier to use. What's the big design shortcoming I'm not seeing?
#95
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I presume you mean the 2-speed Classified Powershift hub, which I really do like but it is very expensive and limits your wheel choices. But if one of the big players took it on along with plenty of wheel and cassette choices then I would be very interested. But a more simple 1x13 is very tempting for me on a road bike and an electronic version can’t be more than a couple of years away. I very nearly built a road bike with Ekar last year, but component availability at the time put an end to it.
#96
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"The way FDs currently work, it doesn't so much pull the chain off the current ring, as it does feed the chain on to the intended one."
...is a good description of front upshifts, but can be misleading as a description of front downshifts. "Feed on to the intended one" is suggestive that the front derailleur primarily guides with respect to the destination, but on a downshift, the front derailleur's role is largely around guiding it off the origin.
My objection to your wording was not about how much horizontal versus vertical guidance a front derailleur applies to a chain.
So, what sort of advantage do these historic cambios offer over a modern derailleur/shifter setup?
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Well that's only an issue while it remains a niche product rather than an inherent problem with the concept. Moving it to the front increases torque and reduces rpm compared to the hub so it might not be quite as slick. Either way you are stuck with a proprietary hub or crank and so it isn't really going to go anywhere unless Shimano/SRAM get involved and it becomes part of a high-end mainstream group. But I think the push to 1xN will probably kill it off in this respect.
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- Q factor.
- No derailleur exists that moves that wide.
- Nothing exists that would move the derailleur (friction would be the easiest option.
- The market is moving to fewer rings (not more).
- Not a big enough market or (maybe) way too expensive or too stupid (even) for kickstarter.
- Etc.
Last edited by njkayaker; 07-20-23 at 03:35 AM.
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Yeah, I know the theoretical question was multiple gears in the front. But he also mentioned the mechanical difficulty of downshiftig in the back (moving to a larger sprocket). I was simply mentioning that a "bail out" situation is easy with a smaller front chain wheel compared to a larger sprocket in the back. that's all. I have no illusion that multiple (beyond 3) in the front is practical.
#100
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Fashion is not really part of it ... they simply are not necessary for most riders. With 11 or 12 cogs (versus five or six) it is easy to have a wide range of ratios with a double chain ring (or even a single) and with modern indexed shifters, easy to get to any of those gears even under load.
The added ratios a triple would provide are beyond what most riders would use, and since rear shifting is quicker and easier, there really isn't a necessity for a triple .... maybe for touring, where a rider might want a really low option for hauling full kit up mountains, but for most riders, a triple offers no benefit over a double.
Also, with front derailleurs now handling a 16-tooth spread (or more) as opposed to ten .... (standard 10-speed gearing was what, 52-42x14-34? or maybe 12-25?) I toured flat lands with a 52-42-32 triple and a 34-toorh big cog. Now I can ride a 50-34 with 11x36 and get almost the same range. Only for mountain touring where a 22-tooth chain ring might be needed, can I see a triple really paying off any more ....
Also, with front derailleurs now handling a 16-tooth spread (or more) as opposed to ten .... (standard 10-speed gearing was what, 52-42x14-34? or maybe 12-25?) I toured flat lands with a 52-42-32 triple and a 34-toorh big cog. Now I can ride a 50-34 with 11x36 and get almost the same range. Only for mountain touring where a 22-tooth chain ring might be needed, can I see a triple really paying off any more ....
I think triples fell out of fashion because most riders simple never used the small ring once they got seven or eight cogs in back.
I have lower gearing and, more importantly, higher gearing than you can get with a 1x or 2x wide range system. I’m not “weak”. I’m smart and know how to design and use a very wide range triple system.
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Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!