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electronic shifting

Old 04-13-10, 09:06 AM
  #1  
4evrplan
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electronic shifting

I find shifting with two separate shifters and figuring out which gear combo. is the best to be unnatural and counter-intuitive versus the more linear shifting in a car with a manual gearbox. Furthermore, derailleurs seem to be a common source of mechanical problems, especially in regards to adjusting them to properly shift into every gear without rubbing or overshooting the largest/smallest cog. And, I can't tell you how many times I've read about home builders (anything from minor mods to radical scratch built recumbants) saying they couldn't use every gear combination on their creations; one more complication to remember.

Well, I thought if you could use a computer to control the shifters, it could use a single up/down pushbutton device to select the gear and keep track of which combo has the next higher or lower ratio, completely hiding the fact that it's two shifters, making it seem like a single linear range. It could be done by attaching the shift cables to stepper motors with a custom controller - really doable stuff here.

If you added some kind of sensors, it could conceivably even monitor the position of the derailleurs and automatically adjust to eliminate rubbing and overshifting by compensating for chain stretch and other problems.

And lastly, it would be very simple to program the computer to avoid certain gear combos, skipping over them transparently and going to the next ratio.

As I was pondering all of this, I thought, "someone's surely done it already", so I google for "electronic bike | bicycle shifter", and sure enough, Shimano has Di2, but it works differently than what I had in mind, where it uses a special derailluer as opposed to a special shifter connected to a standard derailleur.

Even so, it brought up an interesting point. The tone of the articles I read about it had a distinctly negative tone to them. One of the arguments was that they didn't want to depend on a battery, but a small dyno could be used to keep it charged, and if you used a quality capacitor instead of a battery it would outlast the rider. I liken this retro grouchery to old men who refuse to give up their carburetors for the advantages of fuel injection, but I wanted to get a feel for the general opinion.

How would you feel about using such a setup, given all or some of the advantages I've listed, especially virtual linear shifting?

EDIT: When I said "chain stretch", I meant "cable stretch".

Last edited by 4evrplan; 04-13-10 at 12:12 PM.
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Old 04-13-10, 09:33 AM
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It's a decent idea, but the problem is that front shifting and rear shifting are still very different animals- even though DI2 is better than anything else on the market, front shifting under power is still not a flawless endeavor. shifting sequentially as you suggest would result in some front shifts and some rear shifts in a non-predictable order, which most competitive riders would hate.
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Old 04-13-10, 09:45 AM
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Do you mean they'd hate it because the ratios would be close together on some shifts and further apart on others? If so, I see your point.
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Old 04-13-10, 09:49 AM
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Perhaps it'd be best for the controller to stay on the middle chain ring unless you request a gear higher or lower than it can provide? It wouldn't give you the use of all ratios, but it'd keep the spacing more consistent and help with chain line issues.
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Old 04-13-10, 11:03 AM
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The 2 problems of traditional drivetrains that you mention (linear shifting and mechanical problems) are solved by internal hubs like the Shimano Nexus. Unfortunately I don't think they have the same gear range as a traditional triple chainring system.

I think that the main issue is weight. Racers and most recreational riders are willing to live with the shortcomings of a traditional drivetrain because nothing yet has come along that offers the same performance with low weight.

Last edited by noonito; 04-13-10 at 11:16 AM.
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Old 04-13-10, 12:08 PM
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That's also an excellent point. Durability/reliability could be designed into an electronic shift system, but it will add weight. Though, I believe a home builder could put one together for pennies on the dollar compared to the Di2, there is also a cost.
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Old 04-13-10, 01:01 PM
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Road bikes are just getting in to this. Shimano I believe offers an electronic shifting system for road bikes on their highest end components.
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Old 04-13-10, 01:53 PM
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I like the idea of eletronic shifting but I think it will be awhile before it gets mainstream.
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Old 04-13-10, 02:24 PM
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Electronic shifting for the dirt is here: G-Boxx2:





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Old 04-13-10, 02:57 PM
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G-Boxx 2: Now only 15 lbs, but with the brick-like aesthetics that made G-Boxx 1 such a huge hit.
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Old 04-13-10, 04:36 PM
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Maybe someday we will have ultra light shaft driven bikes so it can be accomplished. There are shaft driven bikes on the market but to make them light weight even for the weekend warrior is impossible right now or within pricing reason.
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Old 04-13-10, 04:45 PM
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Take a look at this bike with shaft drive........

http://www.dynamicbicycles.com/buy/Bikes.php?prodid=47#
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Old 04-13-10, 05:10 PM
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Originally Posted by m4ximusprim3 View Post
G-Boxx 2: Now only 15 lbs, but with the brick-like aesthetics that made G-Boxx 1 such a huge hit.
Aesthetics is everything with a drive train for sure

G-Boxx2 is 4400g (9.7 lbs) and since it's replacing a 1500g crankset/BB, 325g cassette, 235g derailleur, some chain, cable and hub weight plus maybe a lb or more of frame plus turning a lot of unsprung weight into sprung i'd say it's not that bad a trade-off for what it accomplishes.

Last edited by ImOKUrSo-so; 04-13-10 at 07:03 PM.
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Old 04-13-10, 05:48 PM
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I just don't see the need for a computer to do a simple task as selecting the proper chainring/cog combo. I like my mountain bikes to be reliable, don't see electronics being reliable let alone making as good a decision or shift as I can on my own. One good crash and what happens then? Riding in sloppy conditions would you get electronically driven chain suck? Heck, my phone isn't even reliable.

Do you have problems with different gate patterns (which aren't linear to my mind) with the various manual auto transmissions?
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Old 04-13-10, 05:49 PM
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hey, what's going on here?
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Old 04-13-10, 06:39 PM
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I wouldn't want my front shifter to shift without me telling it to.

I like the sound of electronic shifting, and if I get enough money for a road bike with a high end groupset then Di2 would be my number one choice. I wouldn't like shifting to be as independant as you're suggesting though.
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Old 04-13-10, 07:22 PM
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Originally Posted by 4evrplan View Post

How would you feel about using such a setup, given all or some of the advantages I've listed, especially virtual linear shifting?
Sure. I'd use it....if-

1. It really has to work - no smoke/mirrors/hype/marketing. I'm talking about years of development and testing before it's released to the public.

2. It must have built in test capabilities. The average rider should be able to troubleshoot any component of the system on the side of the trail at night by the light of a flashlight while a gentle snow is falling. Spare parts should be available at any bike shop worldwide.

3. It has to weigh the same or less than current systems.

4. It has to cost the same or less than current systems.
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Old 04-13-10, 11:02 PM
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do it and show us! interesting idea and i want to see it happen even if it's rough and not tested.
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Old 04-14-10, 09:03 AM
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Originally Posted by bikinfool View Post
Do you have problems with different gate patterns (which aren't linear to my mind) with the various manual auto transmissions?
I haven't driven enough different manuals to know. Yes, the gate pattern isn't a straight line, and I would prefer for that to be the case, but it still makes more sense in my mind than two separate transmissions. Paddle shifters would probably be even better yet, though I haven't had the chance to try those either.

Originally Posted by Dheorl View Post
I wouldn't want my front shifter to shift without me telling it to.
That's not the point. I think you must have misunderstood my description. It wouldn't automatically shift without input, but it would automatically shift to the next higher gear ratio once you told it to shift up or the next lower ratio if you told it to shift down. You just push the button, and it does the rest. It would give you complete control over when and what direction to shift, and would allow you to program it to customize which gear combinations to skip over completely (for example, don't use both big cogs or both small cogs at the same time, or don't use some ratios that are too close to others to really be useful).
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Old 04-14-10, 09:05 AM
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Originally Posted by Dheorl View Post
I wouldn't want my front shifter to shift without me telling it to.
Nevermind. I realized what you're saying. Missed the word "front".
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Old 04-14-10, 09:18 AM
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From everything I'm seeing, it seems like an IGH with a greater gear range would be the best compromise. The problem of course, is that it still weighs more and costs more. So, allow me to pose a new question:

If an IGH were developed with the same or better gear range as a conventional drive train, would you be willing to take the weight penalty?

Or, perhaps a mechanical single-lever shifter could be developed which controls both derailleurs. People have built mechanical systems to shift a manual transmissions linearly in race cars, so why not. The shifter would most likely be heavier than a normal one, but you'd be able to eliminate one.
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Old 04-14-10, 12:19 PM
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The Rohloff doesn't have sufficient gearing range?
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Old 04-15-10, 12:05 PM
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Originally Posted by bikinfool View Post
The Rohloff doesn't have sufficient gearing range?
I was just taking noonito's word for it (post #5), but I guess he may have been talking specifically about the Nexus. I see now that the range of the Rohloff Speedhub 500/14 is very good. http://www.rohloff.de/en/products/sp...ge_comparison/ It's also very expensive.
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Old 04-15-10, 12:09 PM
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Originally Posted by ImOKUrSo-so View Post
Ooooo, I'm liking the look of this.
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Old 04-15-10, 12:29 PM
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I thought the Di2 is a cool idea.

I read about it in the MTB Magazine I picked up for my Rome trip.
They had it all mounted to a Mtn bike and said it worked good. The front auto trims, and the rear can auto adjust and align.

I think with some more development Shimano might have something here. They battery also lasts quite some time.(3 months? if I remember correctly)

I like mechanical things, and usually dislike computers running everything, but I like the concept of Di2.

The magazine said that it provided very smooth and responsive shifting.
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