Automatic shifting bicycle!

[toker_ace]

i think this would be the coolest bike with a jackshaft! I have seen this commercial on T.V before. Imagine having a HT with a sick jackshaft and the bad boy changed gears automatically.Now thats something to look into. here's a link to the bikes.They are a little pricey! $400.00 (bike) + $110.00 (motor) + $159.00 (jackshaft) = $669.00 That's high but not out of reach. here's the link.
Best Road Bikes, Men & Women Hybrid Bicycles, Cruiser Road Bike, Second Hand Comfort Bicycle, Full Suspension Bikes For Sale, Refurbished Bicycles @ Discount Price – Landrider Bikes

[bandito]

Ive seen those bikes on tv for years and always wondered how they know to up shift when you hit a hill. I can see spring pressure going through the gears from say 1st to 7th but the other way to see how it works would be interesting.

[thatsdax]

The problem with Auto shifting is that the shifting occurs at an unknown " to the rider" preset mechanical time or interval. This spells disaster for anyone serious about riding a bicycle. Ever stand on your pedals and shift at the same time? If so.. Then you already know what planting your knees into the pavement feels like. As long as you stay seated on the seat while pedaling "during gear changes, and who knows when that will happen" knee plants into the pavement can be avoided. If you want to install a motor, electric or gas, and use a front crank free wheel to allow for shifting, this too is problematic since a motor applying power when the rear derailleur decides on its own to change gears would spell disaster. What you need to do is install a motor with a front Crank Free Wheel drive setup on a regular bike so you can see how it works and operates. Then, and only then, should you attempt to propagate or move towards an Auto Shifting derailleur setup. My supposition or feeling would be that you would forgo the Auto shifter. The only way I can see an auto shifting bike could work safely is to install a switch that senses the bicycle gear changes, and would automatically throttle down the motor and once the gear change is complete, would automatically throttle back up. Enjoy the ride..

[Kevlarr]

They work off a governor that runs off a belt and pulley behind the cassette, the faster the governor spins the higher gear it selects. You wouldn't need the whole bike just the pulley setup and the derailleur. When I first saw them years ago I thought they were a cool idea but not worth the $400 price tag. Not sure how they'd react to shifting under power though.

[Humsuckler]

junk. total overpriced "fad" junk.

thats why we dont see any big brand companies producing high price autoshifts.....
it wont work. the flyweights move out towards the rim or some **** and shift the gears.

ill say junk just one more time.... "junk"

if you want something noone else has look into an air shifter

[Kevlarr]

Now there's an idea an air shifter! Connect a big paddle to the derailleur so the faster you go the more air pressure pushes on the paddle shifting you into a higher gear!

[bandito]

I like to see how different stuff works Ive never seen an autorider upclose only in pics or on tv. Dax was talking about planting your knee into the pavement, I havnt gone down yet on a bicycle since I started riding again as an adult. I almost lost it once though when I was wearing tennis shoes and my right foot slipped off of the pedal when I went to push really hard it scared the bejeezus out of me. A shoe with an integrated heel is definately a plus.

[BarelyAWake]

Well, there's the NuVinci hub ofc - I dunno about how it holds up to motorized use and it's a bit pricey... The one the forum sponsor links to is electronic, but there's also cable actuated ones - saw one at my local bike shop. Thought about it a bit for my build, but I think SBP's jackshaft is still the best way to go lol

[xlite]

I bought one of those a few years ago. It was only $200 and worked fine but quite heavy. It's gathering dust in a back room. You can't put an engine on them.

[BarelyAWake]

Originally Posted by xlite

You can't put an engine on them.

Because they can't take it? Or cause it'd need a jackshaft?