What is pedal assist?

[Kerrith]

I'm ordering a folding e-bike and have the option of having, or removing, pedal assist.

Because of a limited range of motion of one knee (gunshot wound Vietnam) I'm unable to pedal as I used to with my ten-speed Huffy 40 years ago. In other words, I'll be totally dependent upon the 20" rear wheel 1000w gearless motor and the 48V 20ah batt. If the batt dies while I'm on the road I plan on pedaling the 5 miles home by standing up which I can easily do.

I explained how I'll be using the e-bike and the manufacturer offered to remove pedal assist. I have no idea what this means.

The bike will have front and rear disk brakes.

Please advise.

Thanks,

Kerry

 

[mlt34]

pedal assist means that when you pedal (even lightly), the motor gives power. It's essentially like controlling the throttle by pedaling your feet instead of twisting a hand throttle like you would on a motorcycle.

my opinion is that pedal assists systems are annoying, and also that if you have a knee injury then you won't want to be using it anyways.

more to the point, you should determine if the pedal assist system on the bike you want is a AND or OR situation, meaning if you have pedal assist, does the bike also come with a hand throttle or do you only get one or the other. Because of your injury, you will need a hand throttle.

So I recommend just telling the manufacturer that you want a hand throttle and be done with it.

 

[Kerrith]

Thanks for the explanation. You're right, I wouldn't want to have to pedal to get moving also, the e-bike will have full twist throttle,

Kerry

 

[d8veh]

As long as you have a throttle, it's no problem. The throttle normally overrides the PAS. On a low power bike PAS is easier than a throttle as long as you want to pedal as you go along. Most PAS system these days have several levels that you can select on an a handlebar panel. If you don't have the panel, it'll probably give full power when you pedal, which would be a problem on a 1000w bike. It's normally a two minute job to find the PAS connector and disconnect it if you don't like it.

 

[Kerrith]

Thank d8veh,

Kerry

 

[mlt34]

It's normally a two minute job to find the PAS connector and disconnect it if you don't like it.

Its just important to make sure that it's not a 'one or the other' type scenario. a lot of chinese ebikes I saw at my shop had only the option pedal assist OR throttle.

 

[Kerrith]

For sure I'll reply here again if I have a problem with my new leaf e-bike — http://www.leafbike.com/products/electric-bicycle/20-inch-folding-electric-bike/new-20-inch-1000w-folding-electric-bike-957.html. I've ordered it with an upgraded (48V 20ah) batt which should allow me to ride to and from town (never more than 14 miles 2 x per week). I plan on hauling a Aosom Elite II Bike Cargo trailer.

This is such a great forum. Thanks all,

Kerry

 

[The fingers]

Nice looking trailer also, by the way! 8)

 

[d8veh]

For sure I'll reply here again if I have a problem with my new leaf e-bike — http://www.leafbike.com/products/electric-bicycle/20-inch-folding-electric-bike/new-20-inch-1000w-folding-electric-bike-957.html. I've ordered it with an upgraded (48V 20ah) batt which should allow me to ride to and from town (never more than 14 miles 2 x per week). I plan on hauling a Aosom Elite II Bike Cargo trailer.

This is such a great forum. Thanks all,

Kerry

That bike has 5 levels of PAS and an independent throttle. I forgot to mention that some (not many) of bikes with LCD displays use level 0 for throttle and 1 - 5 for PAS, which means that you can't get instant throttle when you need it. Let us know how your one works when you get it.

 

[Kerrith]

Hi d8veh,

That bike has 5 levels of PAS and an independent throttle. I forgot to mention that some (not many) of bikes with LCD displays use level 0 for throttle and 1 - 5 for PAS, which means that you can't get instant throttle when you need it. Let us know how your one works when you get it.

You're saying it's possible that I'd twist the throttle and not move?

They are still building and testing it—should I ask them for a specific configuration? I don't know what PAS is. :?

Thanks,
Kerry

 

[Kerrith]

What does PAS mean?

 

[cal3thousand]

What does PAS mean?

Pedal Assist Sensor

 

[Kerrith]

Thanks cal3thousand,

Do you know what d8veh is referring to, ". . . which means that you can't get instant throttle when you need it."

I'm concerned because Leaf appears to be willing to customize it to my wants and, it's scheduled to ship in 7 days. I don't want to have to pedal except by standing up in case it breaks down. I want to be able to to twist the throttle and go.

 

[chas58]

Well, it says 40mph with throttle control. You could ask. Sounds kinda strange to me that throttle wouldn't give full power, otherwise what is the point? d8veh obviously has seen something like that.

Hey, what is "carbonsteel?" sounds pretty cool

40mph is possible, but sounds like an exaggeration. Looks like 15-25 in that video.

I would guess 30mph tops with 20mile range is more typical, FYI.

 

[spinningmagnets]

Two types of Pedelec systems that I know of. The more expensive system uses a torque-sensor. The generic term is a "strain gauge", and when placed properly it senses how much bending is taking place on some part of the bike. It sounds odd, but they can accurately sense an incredibly small amount of "strain" on the metal. Justin @ ebikes.ca is developing one of these, rather than just buying from another supplier.

The common variety is a speed sensor. The usual technique is to attach a plastic ring around the Bottom Bracket shaft (BB, pedal axle) that is embedded with a series of small magnets, and a hall sensor/reed switch picks up when a magnet passes by. The computer calculates how much time has passed between one magnet and the next, then it calculates if you are speeding up, maintaining, or slowing down. The computer takes the info and sends a signal to the controller to increase, maintain, or decrease the amount of amps going to the motor.

There seem to be two benefits to pedelec that customers like. One is that they always have their hands free, instead of one hand always managing the throttle, and the other benefit is that if you are running more power than is legally allowed...you have to pedal to get the power, so the police will never accidentally see you zooming by without pedaling.

Some riders have mentioned that they like the pedelec because if they had a throttle, they would always use it, and never get any exercise. I believe for most people, if you are forced to pedal to get power, you will actually use your E-bike less. I always suggest having options...nothing requires you to use the throttle, but it's good to have if you strain your knee and want a "no pedal" month to recuperate.

It's only been recently that I've seen reports of bikes that have both as an option...good to see.

 

[Kerrith]

Can I assume that with mine I'll be able to twist the throttle from stop and it will go or do I have to request that configuration from Leaf? I don't want to have to pedal except in case of batt failure. In other words, mine will not be used for exercise at all.

Thanks,

Kerry

 

[d8veh]

Can I assume that with mine I'll be able to twist the throttle from stop and it will go or do I have to request that configuration from Leaf? I don't want to have to pedal except in case of batt failure. In other words, mine will not be used for exercise at all.

Thanks,

Kerry

For most bikes that have PAS and throttle, the PAS is active all the time except when you use the throttle, which instantly over-rides the PAS. There's lots of different systems: Some only give one level of PAS power - maximum, which can be a nuisance because it can give too much power when you let go of the throttle even when you're not pedalling. You can get a surge of power when you throttle back for a corner because there's a time delay on PAS sensing, so power continues for from between 0.5 to 2 seconds after you stop pedalling. It's no problem if you don't pedal.

The point I made earlier is that some controllers have a nice LCD display with levels 0 to 5. Level 0 is for throttle only (PAS disabled) and levels 1 to 5 are PAS only (throttle disabled). If you want to ride with throttle only, you just select level zero. If later, you want to give your throttle hand a rest, you can select one of the other levels, but you lose instant throttle until you re-select level zero. Other controllers have LCD displays with levels 1 to 5, where both PAS and throttle are active all the time with throttle taking precedence. There'es lots of different systems. Without knowing which controller and display you have it's not possible to say how it works, and I'd be surprised if you get a sensible answer from the vendor, but you should ask anyway if it's important for you. If you get a controller with several levels of PAS, I think you'll be using the PAS rather than the throttle. It's much more convenient. you'll see when you try it.

More unusual, but they crop up from time to time are controllers that require you to pedal before the throttle will operate.

 

[Kerrith]

Thanks for the clarification.
I've been assured that I don't HAVE to pedal from stop.
I'm assuming I could change it easily if I don't like the way it comes.

Kerry

 

[mlt34]

Thanks for the clarification.
I've been assured that I don't HAVE to pedal from stop.
I'm assuming I could change it easily if I don't like the way it comes.

Kerry

I think you should be happy with it. The "twist to go" is pretty much the standard for ebikes, it's tried and true, people like it. I don't think you'll be regretting not having PAS...

 

[Kerrith]

Thanks for the reassurance. I'm very excited; it opens up parts of the Big Isle to me. I can even envision checking it as baggage to the other islands.