In-wheel battery electric bicycles

[shemozzle999]

New Chinese offerings:

http://www.alibaba.com/product-detail/28inch-electric-wheel-with-battery-inside_1657085182.html

http://qyyebike.en.alibaba.com/product/284862027-209543152/high_quality_Mountain_Fashion_Electric_bike_with_EN15194.html

http://qyyebike.en.alibaba.com/product/1959182831-209543290/fashionable_20_foldable_electric_bicycle_with_250W_motor.html

also available in kit form:

http://www.alibaba.com/product-detail/CE-cheap-36v-10ah-electric-bike_1045211266.html

edit: link corrected - sorry no porn

edit: link for kit added

 

[flecc]

The first link seems invalid shemozzle999.

On the second link, not sure what to make of that comment, "with battery inside for woman"
.

 

[Gubbins]

It still looks like the future is hiding an all in one solution for my Boardman......

 

[trex]

It still looks like the future is hiding an all in one solution for my Boardman......

this is rather the last resort solution when you can't find a place to put your battery. This system has high 'polar momentum of inertia', or resistance to turning. It's the opposite of crank drive systems with bottle batteries. The latter don't have this problem and feel so much more like riding normal bicycles.

 

[Gubbins]

Don't understand the terms but get the drift! All the weight needs effort to turn, but once turning will the Wright act like a flywheel conserving the energy input? A bit like on old engine with a heavy flywheel.

 

[shemozzle999]

this is rather the last resort solution when you can't find a place to put your battery. This system has high 'polar momentum of inertia', or resistance to turning. It's the opposite of crank drive systems with bottle batteries. The latter don't have this problem and feel so much more like riding normal bicycles.

Don't understand?

The batteries are stationary fixed to the stationary shaft only the casing body rotates thus no resistance effect.

Methinks your reasoning is clouded by your insistence of all things Woosh

 

[trex]

Don't understand?

The batteries are stationary fixed to the stationary shaft only the casing body rotates thus no resistance effect.

Methinks your reasoning is clouded by your insistence of all things Woosh

Not at this moment.

http://en.wikipedia.org/wiki/Second_moment_of_area

You'd want your bike to have its mass distributed like this:

or like this:

 

[shemozzle999]

You have omitted a the substantial mass of the rider in the diagram which would drastically effect your theory. Notwithstanding the limited bike speed.

 

[trex]

the centre of mass of bike and rider needs to be kept close to middle between the two contact points with the road where the road exerts the reaction forces to minimize deflection effort. On e-bikes, the posture is a bit more towards the rear wheel, hence it's logical to put the battery on the downtube.

 

[Gubbins]

the centre of mass of bike and rider needs to be kept close to middle between the two contact points with the road where the road exerts the reaction forces to minimize deflection effort.

Or else What exactly? I for one dont understand all this gobbledegook, but it sounds a bit like racing cars and bikes where you need to move the weight to make them go around corners at 200 mph.. Surely all this make little difference to an e-bike doing 10 or 15 mph...

 

[RobF]

Battery position makes a difference to the feel of the ride.

I'm not keen on batteries on the carrier, or even behind the seatpost.

Low down on the downtube is the best I've come across.

Never tried a battery in-wheel bike.

 

[trex]

Or else What exactly? I for one dont understand all this gobbledegook, but it sounds a bit like racing cars and bikes where you need to move the weight to make them go around corners at 200 mph.. Surely all this make little difference to an e-bike doing 10 or 15 mph...

it's just a bit of technical banter. Shemoz keeps us posted with what's new and I feel it's useful to point out the bad points so everyone can make an informed purchase decision. The CB bikes are sporty and pretty, my guess you are keen on a hub kit. I honestly think crank drives are much better.

 

[shemozzle999]

With a fixed straight ahead rear wheel and a twisting front wheel where exactly is the pivot point on the bike?

 

[flecc]

Most bicycle like for me was the Giant Lafree Twist with the first Panasonic unit, motor unit and battery in the centre and low. Neither the well weight balanced Torq (front motor and rear of seatpost battery) or the Quando were anywhere near as good at being normal bicycles in handling.

For a real battery-in-wheel experience the 30 mph Tidal Force took some beating:

 

[trex]

With a fixed straight ahead rear wheel and a twisting front wheel where exactly is the pivot point on the bike?

the pivot point is approximately in the middle, prorata of the weight at the two poles, but the user input required to deflect the bike when turning is much more than if both polar weights are located near the centre of gravity. This effort is proprtional to the sum of (Mass * square of distance from the centre of gravity).

http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics

 

[shemozzle999]

Most bicycle like for me was the Giant Lafree Twist with the first Panasonic unit, motor unit and battery in the centre and low. Neither the well weight balanced Torq (front motor and rear of seatpost battery) or the Quando were anywhere near as good at being normal bicycles in handling.

For a real battery-in-wheel experience the 30 mph Tidal Force took some beating:

Bet it was like the 3 litre Ford Capri and the E type - great in a straight line but useless at going around corners

 

[RobF]

Bet it was like the 3 litre Ford Capri and the E type - great in a straight line but useless at going around corners

I liked those rear wheel drive Fords - you could have some tail out fun at relatively low speeds.

 

[shemozzle999]

Perhaps I need to fit a rear spoiler to my bike

 

[shemozzle999]

I liked those rear wheel drive Fords - you could have some tail out fun at relatively low speeds.

My passion was for front wheel drive Mini Coopers never really liked rear wheel drive -seen too many BMW's struggling in the winter

 

[flecc]

Bet it was like the 3 litre Ford Capri and the E type - great in a straight line but useless at going around corners

That Tidal Force was very much a straight line bike, felt more like a motorbike but without the throwability. Unsurprisingly they failed, French car company Matra licenced the design and produced this concept e-bike. At least it had great disc brakes, unlike the rim brakes on the fast and very heavy Tidal Force: