Automatic gear shifter?

[Dogtrousers]

It's something that gets reinvented every so often, like oval chainrings, L-shaped cranks and indicator / brake light systems.
Like all of the above, it then sinks without trace, because it's a terrible idea.
The latest iteration I can find was this from 2016, but it's like the Deal Drive from the mid-80s.

I never understood why the Deal Drive never caught on.

A super lightweight, simple and efficient solution to a problem that everyone agrees needs to be solved. (Fact check: Some of this statement may be open to question)

Some more recent weird and wonderful attempts:
https://vectr-gear.com/
https://arstechnica.com/cars/2023/1...t-is-wild-and-spiky-and-could-be-a-big-shift/

 

[Dogtrousers]

Not quite the same subject but aren't front mechs supposed to be dead by now?

A couple of years Ganna rode a time trial with a "front mech killer" two speed chainring (not automatic transmission). But I've not heard of it since.

 

[PaulSB]

You think it is dreadful. Every review I have seen thinks the opposite.

And while I haven't yet tried a bike with Di2, I can only imagine it being of benefit, since I do what it does almost every time I change rings. The change between rings is always much bigger than the change between two sprockets, so you almost always want to change both together, in the same direction (opposite effect).

And you can always turn it off if you don't like it.

Yes, after riding several hundred miles I've concluded it's dreadful. My preference for selecting a gear is how I feel, wind, road and how the group is riding at that point. I don't like the system making uninformed changes which take no account of the local situation. Shifting is so quick and simple any misjudgement I might make is corrected in a flash.

On the other hand you have not ridden di2 and can only imagine it's a benefit based on the reviews of unknown individuals. I prefer to reach an opinion based on my personal experience. I could point you to reviewers who have reached a similar conclusion. These took five minutes to find.

I switched it off many months ago.

 

[Chislenko]

I've never heard of one but imagine someone, somewhere will have dreamt it up.

One only has to ride di2 with the "auto" setting, I don't know its name, to understand this can never work. Shimano in their wisdom introduced a di2 setting which shifts the rear derailleur when the rider shifts the front. It's dreadful.

Gear selection on a bike is about the rider's feel and intuition. No automatic system could better that.

My mate has his set up that way, I think something along the lines of if you go from big front to small front it auto shifts the rear something like three cogs because it thinks that's where you should be. My di2 isn't set up to do it, you just do it yourself so I presume it can be programmed out.

 

[Ming the Merciless]

What’s wrong with friction shift?

 

[Dogtrousers]

What’s wrong with friction shift?

They are the future!

If you slacken them off just right the spring in the mech will give you automatic upshifts.

 

[PaulSB]

My mate has his set up that way, I think something along the lines of if you go from big front to small front it auto shifts the rear something like three cogs because it thinks that's where you should be. My di2 isn't set up to do it, you just do it yourself so I presume it can be programmed out.

Yes, that's it but on mine it was two cogs. I've set mine to "manual" or whatever Shimano call it.

 

[TheDoctor]

What’s wrong with friction shift?

Exactly! My Brompton has now got a three speed hub gear (indexed) and a three speed derailleur (friction).
I can't see that being confusing at all.

 

[presta]

Simply set your desired cadence once (how many pedal rotations feel comfortable for you) and the Enviolo Hub will constantly adjust its internal gear ratio to maintain a steady smooth cadence regardless of the speed or riding conditions

But that's just the point, optimum cadence is not a constant, even for one particular rider, it depends on power output, and thus anything that affects power, such as speed and gradient. (By optimum I mean most efficient, not a subjective opinion, although IME those two turned out to be the same.)

 

[rogerzilla]

The reason automatic shifting is a bad idea on a bike is simply that you are not a machine, and you feel different at different times. A car engine doesn't want to plod at 70rpm towards the end of a long ride when it's tired.