Automatic gears!?

dave2041

http://www.gizmodo.co.uk/2012/01/two-speed-internal-gear-hubs-designed-in-the-sixties-now-appearing-on-a-bicycle-near-you/

Also just a thought:

Wouldn't it be interesting to have an automatic gear changer based on your "ideal" cadence. So you're in an easy gear and the legs are going crazy, the cadence is too high and the gear is changed. Cadence is lowered initial by the change in resistance but you speed through this gear and again cadence is too high, next gear.

Alternately you brake sharply and you cadence falls drastically, the gear is lowered untill your ideal cadence is met...

Just a thought!

CiB

Never. Imagine finding the sweet spot climbing a hill and the bikes decides you need to be in another gear and changes just as your foot passes TDC. Crump. Goolies? Meet Mr Crossbar...

A continuously variable system might do the job though; on second thoughts no it wouldn't. Legs don't have a power band like engines - it would never be just right, in the way that 53/23 is just a bit nicer than 39/19 (for example, made up too so don't knock it as wrong), or how sometimes cruising in a big gear is right but two days later spinning at 110 on exactly the same road is the right thing to do.

ToeKnee

CiB wrote:

Never. ...

+1 ... Is it April already?

bails87

In theory.....

How about a CVT with a trim lever, that allows you to set the ideal cadence.

You're riding along at 20mph, doing 80 rpm, decide you want to spin your legs a bit more, so shift the lever a bit, it changes to give you a gear which means 100rpm, and keeps you at that cadence regardless of speed until you move the lever again. Sensors make sure the gears change at the best position in the revolution.


'Normal' gears would be cheaper and easier, but still....

CiB

Bails - the CVT that you describe would need a pressure switch under the saddle like the one in my car that suppresses the radio until I put the seat belt on, so that when I knock it up a gear or two and leap out of the saddle to launch myself up a climb and there's a greater resistance to my legs of awesome [(c) DDD] that effectively keeps me at the same cadence when stood up, the CVT does the same trick.

Still not keen. I will have Di2 or whatever it is next year. I like that.

bails87

CiB: It all sounds so simple, Our Dear Leader has just announced cheap loans for entrepreneurs.....I think I'll start up a new company.....

rolf_f

Hmmmm, not quite sure I see the point! I think we can manage with the physical exercise of shifting a little lever and I trust my brain to know what gear I want to be in more than one made by the likes of Shimano etc

Ultimately, with cars you are not the engine so you don't necessarily have the mechanical sympathy to know what the optimum gear is. I think with your own body, you probably do!

tiny_pens

Been done years ago by a company called Nuvinci. Problem is that after years of development, the hub still weighs something like 5kg ( I think it was about 9kg when they started). Too heavy to become mainstream (i.e. not on an electric bike that already weighs loads) even before you consider the costs of the thing.

bails87

Rolf F wrote:

Ultimately, with cars you are not the engine so you don't necessarily have the mechanical sympathy to know what the optimum gear is. I think with your own body, you probably do!

hmmm, I see more people grinding along on bikes at 30rpm than I see people in cars doing 7000rpm

rolf_f

bails87 wrote:

Rolf F wrote:

Ultimately, with cars you are not the engine so you don't necessarily have the mechanical sympathy to know what the optimum gear is. I think with your own body, you probably do!

hmmm, I see more people grinding along on bikes at 30rpm than I see people in cars doing 7000rpm

There you go - can you imagine the sight of all the 30 rpm'ers bailing off their bikes because it is making their legs go all thrashy?

desweller

It would be just like an auto transmission in a car. Utterly awful for anything apart from noodling along on the flat.