Ghostly bike! Will a moving e-bike balance without a rider?

[eBoy]

Evening, throttle jockeys!

Something's bugging me that I'd like to know! If I fix the handlebars of my bicyclette with a rope, so they are fixed rigidly straight forward, and fix the twist-grip so that the power's on full, then launch the bike forward across a smooth field, will it keep upright by itself and zoom off into to the distance? If no-one knows, I may give it a try!

Johnny

 

[neptune]

It will fall over. A pilot is necessary to balance the bike.

 

[JohnCade]

Assuming nothing like a bump or gust makes it deviate that yes I it should. But in practise something will so the rider compensates for those things. If you fitted it with RC and got to be good at controlling it it would probably ride around on its own like a proper ghost bike.

 

[Deleted member 4366]

It will fall over, but if you don't fix the handlebars it will stay upright and go more or less straight.

I hope you're not hoping to deliver a bomb somewhere or something else unpleasant. I will be passing your details to MI5 just in case.

 

[Fordulike]

Evening, throttle jockeys!

Something's bugging me that I'd like to know! If I fix the handlebars of my bicyclette with a rope, so they are fixed rigidly straight forward, and fix the twist-grip so that the power's on full, then launch the bike forward across a smooth field, will it keep upright by itself and zoom off into to the distance? If no-one knows, I may give it a try!

Johnny

As you appear to be a chap who likes to experiment and tinker, why don't you attach a motorized gyroscope to the saddle. Then it won't fall over

 

[eBoy]

Tee hee, chaps!

I think I'll give it a try in the park, with an oppo to catch it before it gets too far away. I'll have a go with D8V's loose handlebar technique, and then with fixed handlebars, if necessary. I got the idea because a pal had a little toy r/c motorbike. It didn't seem to have any gyro mechanism. It didn't steer by turning the front wheel, but by simply slanting the whole wheel and forks assembly quite minutely to the left or right, if you see what I mean. Bikes are full of mystery - if I want to go to the right, on my motorbike, I can do it by pushing the right handlebar grip forward, which you'd think would make me go leftwards. But it doesn't - it takes the bike to the right! Never quite worked out what's happening there. Spooky!

Don't stay up all night worrying about this, throttle jockeys! LOL!

Johnny

 

[VictoryV]

Tee hee, chaps!

I think I'll give it a try in the park, with an oppo to catch it before it gets too far away. I'll have a go with D8V's loose handlebar technique, and then with fixed handlebars, if necessary. I got the idea because a pal had a little toy r/c motorbike. It didn't seem to have any gyro mechanism. It didn't steer by turning the front wheel, but by simply slanting the whole wheel and forks assembly quite minutely to the left or right, if you see what I mean. Bikes are full of mystery - if I want to go to the right, on my motorbike, I can do it by pushing the right handlebar grip forward, which you'd think would make me go leftwards. But it doesn't - it takes the bike to the right! Never quite worked out what's happening there. Spooky!

Don't stay up all night worrying about this, throttle jockeys! LOL!

Johnny

Look up "Sperry's Rule" of gyroscopic precession on google. Bike wheels have strong gyroscopic properties. It will explain why you have to steer a bike at low speed using the handlebars, and then lean it to steer at high speed. It is that transition that has to be learned with a two wheel bike.

 

[Fordulike]

Look up "Sperry's Rule" of gyroscopic precession on google. Bike wheels have strong gyroscopic properties. It will explain why you have to steer a bike at low speed using the handlebars, and then lean it to steer at high speed. It is that transition that has to be learned with a two wheel bike.

Just did and my brain exploded into the stratosphere

 

[VictoryV]

Just did and my brain exploded into the stratosphere

part of my RAF Halton Apprentice training in 1963 as a "navigation instruments fitter" - it gets easier after 50 years!

 

[eBoy]

Thanks, throttle jockeys - and Victory V. I'll re-read Sperry at bedtime - it may replace the sleeping-tablet that matron brings round to me nightly! LOL!

I looked on Youtube and saw some kids rolling a pushbike down a hill. It seemed to want to stay upright but soon came to wobbly grief.

It's amazing how quickly balance kicks in. If you, say, sit on a static bike and lift up your feet, you cannot balance for toffee. But just a mild push on the pedals, and almost instantly, after about three feet or so of travel, you're on your way, as right as ninepence.

I also remember Kermit the Frog riding a bike, and he seemed to make easy work of it all!

Johnny

 

[mfj197]

If you have the bars rigidly fixed ahead it'll fall over quickly, but if the bars are free to move you'll get a good amount of distance. That distance may well be in an arc though.

 

[anotherkiwi]

It's amazing how quickly balance kicks in. If you, say, sit on a static bike and lift up your feet, you cannot balance for toffee.

I used to be the young smart alec who would stop at the lights and balance the bike till green with my feet strapped in. It can be done with training and a reasonable sense of balance (impossible on the way home from the pub...).

 

[VictoryV]

If you have the bars rigidly fixed ahead it'll fall over quickly, but if the bars are free to move you'll get a good amount of distance. That distance may well be in an arc though.

Searching for "runaway dirt bike" found

which shows it is perfectly possible

 

[mfj197]

Good example. Looks a bit chaotic for all involved - hope there weren't any injuries!

 

[flecc]

I used to be the young smart alec who would stop at the lights and balance the bike till green with my feet strapped in. It can be done with training and a reasonable sense of balance (impossible on the way home from the pub...).

As well as on bicycles, always used to do that on my last motorbike, Honda CB500R, it was well balanced anyway and I could last any lights phase.

Weird thing is that I have such poor balance on my feet, I can't stand on one foot without wobbling and having to put the other down. Just as well we don't have the American sobriety tests, I'd fail ever time. Even as a teenager I used to remark that I should have been born with wheels instead of feet.
.

 

[D C]

http://gearjunkie.com/how-do-bikes-stay-upright

Interesting explanation.

Dave.

 

[Black Dog]

There's a superb video on Youtube of a guy riding a Suzuki Hayabusa who attempts a wheelie and falls off the back at about 40 mph. The bike continues riderless and in a straight line for about quarter of a mile, when it hits a tree, still upright. A two-wheeler with the wheels rotating as gyroscopes is remarkably stable.

 

[mfj197]

There's a superb video on Youtube of a guy riding a Suzuki Hayabusa who attempts a wheelie and falls off the back at about 40 mph. The bike continues riderless and in a straight line for about quarter of a mile, when it hits a tree, still upright. A two-wheeler with the wheels rotating as gyroscopes is remarkably stable.

Yes, as long as the forks are free to move. If the forks are rigidly fixed straight ahead it won't stay up, but if there is even a little free play it'll keep going.

 

[Black Dog]

Bikes have a remarkable ability to manage themselves, as long as some damn fool human doesn't interfere.