electric assisted bikes & their speed?

I am considering getting an electric motor assisted bike.

1) I assume you can use it as a regular bike without the electric assist, meaning it doesn't add a drag to pedaling, other then the extra weight on the bike.

2) Are they typically variable speed or high/low or what?

3) They always talk about "top speed". So what happens if you pedal hard at this speed? Does the electric motor sort of govern your speed? Say it has a top speed of 15 mph and I am going down a hill at 20 mph and turn it on, would it add drag and slow me down or do nothing or increase my speed?

Re: electric assisted bike & their speed?

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Re: electric assisted bike & their speed?

Brock said:

1) I assume you can use it as a regular bike without the electric assist, meaning it doesn't add a drag to pedaling, other then the extra weight on the bike.

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It depends upon the type of system. A geared motor, especially a DC motor with brushes, will add some drag when pedaling. A hub mounted AC motor will add the least drag. However, they will all be harder to pedal than a bike without a motor. IMHO such a bike is best used either with electric assist or with the motor alone. Pedaling without the motor will be a chore due to the extra drag and weight.

2) Are they typically variable speed or high/low or what?

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Most of the ones I've heard of, except the very cheap ones, vary the duty cycle of the motor in order to vary the speed. There are some that just have an on/off switch. I'd recommend staying away from those.

3) They always talk about "top speed". So what happens if you pedal hard at this speed? Does the electric motor sort of govern your speed? Say it has a top speed of 15 mph and I am going down a hill at 20 mph and turn it on, would it add drag and slow me down or do nothing or increase my speed?

Click to expand...

Again, it depends upon a lot of factors, especially the gearing. All motor assisted bikes have a no load top speed. This is the speed the motor will turn the wheel at by itself. It is always somewhat more than the rated top speed of the electric assist. Therefore, you will get electric assist up to this slightly less than this no load speed although the amount will get smaller and smaller as you approach it. Above the no-load speed the motor would probably start acting as a brake. However, operating in this manner might cause harmful voltages feeding back into the control system/battery so some manufacturers don't recommend it. Also, DC motors can "birdsnest" if you exceed their rated speed by a significant margin. This has actually happened with DC traction motors on trains when the train's brakes failed and it ran away going downhill. While the result wouldn't be as dramatic with an electric assist bike, the traction motor birdsnesting could cause the wheel to lock up, resulting in a fall.

If I ever personally decided to use an electric assist bike (I have no need of one right now) I would probably build my own similar to this one since most of the available ones can't even match my normal unassisted riding speeds of 20 to 25 mph, let alone exceed them. Here's his description of the bike. His bike manages 45 mph on the level (adequate to keep up with traffic in my area), and one video shows the no load speed of the wheel at ~70 mph, so up to this speed downhill there would be some power assist. He claims that by using a larger battery/controller the motor is capable of powering a bike to around 60 mph on the level.

Re: electric assisted bike & their speed?

I have known a couple that do better then normal bikes.

They are heavier. no matter what.

If you are looking for an electric assisted bike, I have seen a bunch, but the best ones seem to require you to pedal at least some and this one can usually 4x your power, which gets around many of the laws of where the bike can be used.

I almost purchased one of these, but my use for it because of a change in job disappeared. They can be had for about $600.

http://abc.eznettools.net/D300013/X300109/eBike1.html

It can be easily modified to allow you to go as fast as you can pedal. Most of the bikes because of laws limit the max assist to 15-23 mph. This one can be modified.

Let me know if you want more info.

If you want a bike that propells you with a motor without pedaling you are going to have to keep looking. I can't help there.

Re: electric assisted bike & their speed?

Thanks all. Nope I definitely want to pedal and do so when I am just out by myself. I will be moving to about a mile from my work if things go well. It would be about a 500 foot drop to work, which is good, just getting home wouldn't be as fun so an assist would be nice and I either have to bring along my office attire or wear it for the ride.

Re: electric assisted bike & their speed?

Any faster than 25mph (depending on local laws) and you'll probably have to register it as a motorcycle.

( In my area, motorized scooters and bicycles have a maximum limit of 16mph and can only be ridden on bike lanes or streets with speed limits less than 35mph )

Re: electric assisted bike & their speed?

yuandrew said:

Any faster than 25mph (depending on local laws) and you'll probably have to register it as a motorcycle.

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Here in NYS motorized bicycles (standard bicycles with motors attached) are illegal, period, and mopeds are considered limited use motorcycles (license, helmet, registration, and in some cases insurance are required).

List of state moped laws

I tend to think the politicians who make these laws are paid off but the automakers to purposely discourage any form of alternate transportation. IMHO, anything small like a bicycle with a top speed of 50 mph or under (meaning that it can't use freeways) shouldn't be required to have insurance, registration, or a license to operate. The only requirement should be a minimum age of maybe 16 to 18.

Re: electric assisted bike & their speed?

Probably easiest just to ride a regular bike with low gears but rollerblading to work and walking back would be another option.

If no pedaling is OK, a Segway is legal to use in most places except San Francisco (where they are available for rent anyway). Even the 2004 ban on motorized scooters in NYC specifically excluded "self-balancing, two non-tandem wheeled devices."

Re: electric assisted bike & their speed?

This is all great info.

So does anyone have an electric moped or electric assisted bike?

Re: electric assisted bike & their speed?

Have you checked out the ZAP (Zero Air Pollution) bikes? Evidently there is a kit you can adapt to any bike, and it can be disengaged from the wheel for 'normal' pedaling. This site has a bunch of customer reviews..

http://www.electric-bikes.com/zap.htm


electric trike.

Re: electric assisted bike & their speed?

I actually used one of the Chargers for 2 weeks. It was still like riding a bike, but just easier and faster.

Re: electric assisted bike & their speed?

wow lookit these; made in USA, 550 lb capacity carries a load;

http://www.worksman.com/pav.html


giant pic; http://www.worksman.com/images/PAV/Image21.gif

** Electric Motor Kits. We currently offer two electric systems. The simplest is a front wheel mounted friction drive which rubs against the front tire to assist with power when needed. This is a good choice for limited requirements at a cost of $499. The deluxe system is the front hub electric system which actually makes the PAV3 into a sophisticated and powerful vehicle. The Hub motor is integrated into the front wheel and is powerful, silent and amazing. Cost is $1250 for this up-charge. Check your local laws regarding use of electric vehicles..."

Re: electric assisted bike & their speed?

bfg9000 said:

If no pedaling is OK, a Segway is legal to use in most places except San Francisco (where they are available for rent anyway). Even the 2004 ban on motorized scooters in NYC specifically excluded "self-balancing, two non-tandem wheeled devices."

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Even though they're legal to use here in the streets remember that the Segway is designed specifically to be used on sidewalks, and thanks to our idiotic citywide sidewalk cycling ban they're forbidden there. For some reason electric wheelchairs are allowed on sidewalks even though they're usually heavier than bikes, can move just as fast, are far less maneuverable, and the driver is usually an elderly or disabled person with poorer reflexes than the average cyclist. If the ostensible goal is to protect pedestrians then electric wheelchairs should be one of the first things to be banned from sidewalks. So should cyclists under 14 since this age group usually causes the most problems when riding, but here again in their illogic the City Council allows them to cycle on sidewalk. Like I said earlier, I strongly feel that legislators purposely restrict, license, and or ban many alternative forms of transportation because they are beholden to the automobile lobby. In NYC especially we should encourage use of bicycles, electric or otherwise, Segways, etc. by having zero restrictions on where they can be used. Many people who would otherwise cycle don't because they have a choice of either riding on the sidewalks and risking a $1000 fine/15 days in jail, or risking getting killed by riding on crowded streets where many drivers routinely zip past red lights. Bike lanes really aren't a help, either, unless there is a physical barrier between the bikes and automobile traffic. Sad to say, 99% of the time this isn't the case.

Re: electric assisted bike & their speed?

Well said, jtr1962.

Re: electric assisted bike & their speed?

Article on "Critical Mass" bicycle politics in San Francisco.

And some history on Critical Mass in San Francisco.

-Bill

Re: electric assisted bike & their speed?

Has anyone heard of a moped (Tomos/Puch/or such) being converted to electric? I'm aware of electric scooters but I'm specifically looking at mopeds (must have pedals).

Re: electric assisted bike & their speed?

Brock said:

1) I assume you can use it as a regular bike without the electric assist, meaning it doesn't add a drag to pedaling, other then the extra weight on the bike.

Click to expand...

You do have to drag the motor along, but it's not a very noticeable drag in the type of bike that usually gets sold (motor in the hub). If it's chain/gear/belt driven then you'll feel it much more, but such bikes are usually those that are made by people in their garages with an angle grinder, a welder and and a few old pipes.
I don't know if there exist bikes with a clutch assembly that disengages the motor; one of those would be pretty much drag-free.

2) Are they typically variable speed or high/low or what?

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Again, there's no telling if the bike's of the homemade/supercheap variety, but the normal ones have either a lever or a handle that's gradual. Like a motorbike, in other words... except without the performance.

3) They always talk about "top speed". So what happens if you pedal hard at this speed? Does the electric motor sort of govern your speed? Say it has a top speed of 15 mph and I am going down a hill at 20 mph and turn it on, would it add drag and slow me down or do nothing or increase my speed?

Click to expand...

You'd probably damage the motor or the electronic controller.

My personal suggestion (I know it hasn't been asked, but since the internet gives me the ability to suggest things to people whether they want to or not I'm damn well going to): ditch the electric bike idea. They are all crap.
Expensive, awfully short range and heavy and inefficient SLA batteries.
Oh, and slower than a go-ped.

Get an old-style dinosaur-burning moped, even a tiny 50cc one. You won't be a part of the ecological tree-hugging movement (although four-stroke 50ccs consume ridiculously small amounts of fuel), but you'll be able to actually go up a hill, move faster than a turtle on narcotics and go farther away than the next block.

Re: electric assisted bike & their speed?

..just remember; the turtle won the race...

Re: electric assisted bike & their speed?

TedTheLed said:

wow lookit these; made in USA, 550 lb capacity carries a load;

http://www.worksman.com/pav.html


giant pic; http://www.worksman.com/images/PAV/Image21.gif

** Electric Motor Kits. We currently offer two electric systems. The simplest is a front wheel mounted friction drive which rubs against the front tire to assist with power when needed. This is a good choice for limited requirements at a cost of $499. The deluxe system is the front hub electric system which actually makes the PAV3 into a sophisticated and powerful vehicle. The Hub motor is integrated into the front wheel and is powerful, silent and amazing. Cost is $1250 for this up-charge. Check your local laws regarding use of electric vehicles..."

Click to expand...

There is actually an old man in my city that drives these around on the street. His is electric, too. Doesn't seem to go very fast, though.

Re: electric assisted bike & their speed?

TedTheLed said:

..just remember; the turtle won the race

Click to expand...

The turtle won the race because the hare was stupid.

I'm not saying everybody should get a Yamaha R1 or a Hayabusa, just that at least some power and range are good things to have, and electric bikes don't give you those.

Either get a gas-powered moped (you could maybe convert it to LPG or something if it's a four stroke; its already low fuel cost would become negligible) or wait for fuel cells (or important developments in lithium battery technology). Current batteries are too inefficient to run small vehicles.