Usually my google-fu lets me find out someone else has already thought of everything I can imagine, and I can then see just how bad an idea it is before I try it out. :lol:
THis one, though, I havent' found yet, after a couple of hours of poking around and reading forums and articles on regular biking sites.
Since this isn't ebike-specific, I considered posting this up on a regular biking forum, but since many of the experts on those sites don't seem to like non-traditional suggestions or ideas, I figured I'd try it out here on ES first.
Anyhow: Has anyone ever seen an existing system to use a single shifter that will "automatically" shift front and rear derailers thru their most effective combinations from highest gear to lowest, and back?
Presently all the systems I know of control each derailer separately. If one happens to be at top speed, largest chainring in front and smallest in back, then suddenly needs to slow to a stop for some reason, it can get a little complex for someone with slow reactions and/or coordination problems (like me) to downshift on both shifters at the same time as braking and signalling a stop (presuming no brake lights, just hand signals). For me personally, it's pretty much impossible, and I might be able to downshift one derailer and brake--and whichever brake I have to use means it's only the *other* hand's derailer that gets downshifted.
Example: a bike has a front triple chainring, and a rear six-sprocket cluster, there's 18 possible combinations, some of which are duplicates of each other in gear-inches / etc.
So, couldn't a simple mechanical system use a single shifter to control both derailers to shift from each of the possible combinations to the next?
Electronically, with something like pull-and-hold servos to manage the derailer cables, I can imagine a few ways to do it--at least one of which wouldnt' require an MCU and custom programming to do it, but none of these are really "simple", and all of them require a significant power source to control and operate them, and they won't work without power--they'd automatically let each derailer drop back into it's lowest-tension mode.
Geared / linear actuators could be used instead of the above, so that no power is required to maintain a shifter position. But it's still not simple and still requires power to shift.
But I am apparently too tired and distracted to think of any mechanical way to do this, other than a little clockwork gearbox that would take a single shifter input and convert it to two separate shifter outputs. And I don't really know how to design such a gearbox, much less make one. :/
Any ideas? Existing systems? New ways? Am I just crazy? (don't answer that :lol
FWIW, what got me thinking about this was the bike I"m building for Bill, and how I could simplifiy shifting for him. The only pedal bikes he's had were all singlespeed coaster-brake types (everything else on two wheels has been a motorcycle of one size or another). He's not incapable of dealing with the shifting, but the easier it is the more likely he'll be able to use the gears to help him exercise with it properly without injuring his knees/etc by using the wrong gears for startups/etc.
(Many people I know that ride (or rode) bikes don't shift at all cuz they "forget" or because it is "too complex" to remember which gear is for which speed, so they leave it in a "middle gear"...eventually they get tired of how hard it is to startup from a stop or go up a hill, or not be able to pedal faster, because they even forget the shifters are there at all, or how to use them, or whatever, and then they stop riding the bike at some point and give up on the idea. I don't know if this would simplify things enough for them or not, but....).
THis one, though, I havent' found yet, after a couple of hours of poking around and reading forums and articles on regular biking sites.
Since this isn't ebike-specific, I considered posting this up on a regular biking forum, but since many of the experts on those sites don't seem to like non-traditional suggestions or ideas, I figured I'd try it out here on ES first.
Anyhow: Has anyone ever seen an existing system to use a single shifter that will "automatically" shift front and rear derailers thru their most effective combinations from highest gear to lowest, and back?
Presently all the systems I know of control each derailer separately. If one happens to be at top speed, largest chainring in front and smallest in back, then suddenly needs to slow to a stop for some reason, it can get a little complex for someone with slow reactions and/or coordination problems (like me) to downshift on both shifters at the same time as braking and signalling a stop (presuming no brake lights, just hand signals). For me personally, it's pretty much impossible, and I might be able to downshift one derailer and brake--and whichever brake I have to use means it's only the *other* hand's derailer that gets downshifted.
Example: a bike has a front triple chainring, and a rear six-sprocket cluster, there's 18 possible combinations, some of which are duplicates of each other in gear-inches / etc.
So, couldn't a simple mechanical system use a single shifter to control both derailers to shift from each of the possible combinations to the next?
Electronically, with something like pull-and-hold servos to manage the derailer cables, I can imagine a few ways to do it--at least one of which wouldnt' require an MCU and custom programming to do it, but none of these are really "simple", and all of them require a significant power source to control and operate them, and they won't work without power--they'd automatically let each derailer drop back into it's lowest-tension mode.
Geared / linear actuators could be used instead of the above, so that no power is required to maintain a shifter position. But it's still not simple and still requires power to shift.
But I am apparently too tired and distracted to think of any mechanical way to do this, other than a little clockwork gearbox that would take a single shifter input and convert it to two separate shifter outputs. And I don't really know how to design such a gearbox, much less make one. :/
Any ideas? Existing systems? New ways? Am I just crazy? (don't answer that :lol
FWIW, what got me thinking about this was the bike I"m building for Bill, and how I could simplifiy shifting for him. The only pedal bikes he's had were all singlespeed coaster-brake types (everything else on two wheels has been a motorcycle of one size or another). He's not incapable of dealing with the shifting, but the easier it is the more likely he'll be able to use the gears to help him exercise with it properly without injuring his knees/etc by using the wrong gears for startups/etc.
(Many people I know that ride (or rode) bikes don't shift at all cuz they "forget" or because it is "too complex" to remember which gear is for which speed, so they leave it in a "middle gear"...eventually they get tired of how hard it is to startup from a stop or go up a hill, or not be able to pedal faster, because they even forget the shifters are there at all, or how to use them, or whatever, and then they stop riding the bike at some point and give up on the idea. I don't know if this would simplify things enough for them or not, but....).
