Ebike for kids

[Az.]

Thank you for your explaination. I appreciate it
We have a 250watt bike at home and its very bad and hardly gets us uphill and we have had a 1000watt kids bike that wasnt any good either so our experience is from that.

I appreciate everyones concern but im here for help.
Wether a hub motor brings enough torque or if we should go for a tongsheng tsb, I dont have any experience so thats why im here asking

Speed limit here for assist is 20km/h i believe or 25 and I have no intention of going above that, there is no reason what so ever, we have plenty of hills here so we need that power to bring us uphill.
Thank you

Speed limit is 25km/h and motor rated power limit for adults is 250W (for EAPCs), so 1kW will be 4 times that.

I am 90kg and my bike with 250W rated motor takes me up any hill (including very steep hills in local forests). I ride mostly on 1st and 2nd level of assistance. 3rd is reserved for very steep hills and only when I don't want to make any effort. 4th level of assistance is insanely overpowered.

Just to be sure we are on the same page. Do you want to install 1kW motor on a bike like this one?

Apollo Envy Junior Hybrid Bike - 20" Wheel | Halfords UK

Shop the latest Apollo Envy Kids Hybrid Bike - 20" Wheel at Halfords UK

www.halfords.com

 

[Dixonk]

I

Speed limit is 25km/h and motor rated power limit for adults is 250W (for EAPCs), so 1kW will be 4 times that.

I am 90kg and my bike with 250W rated motor takes me up any hill (including very steep hills in local forests). I ride mostly on 1st and 2nd level of assistance. 3rd is reserved for very steep hills and only when I don't want to make any effort. 4th level of assistance is insanely overpowered.

Just to be sure we are on the same page. Do you want to install 1kW motor on a bike like this one?

Apollo Envy Junior Hybrid Bike - 20" Wheel | Halfords UK

Shop the latest Apollo Envy Kids Hybrid Bike - 20" Wheel at Halfords UK

www.halfords.com

Good for you that you find your 250watts to be enough, thanks for sharing. I think youve made your point and opinion clear. I appreciate you.

We want more than what we need for headroom, we can always limit if needed.

 

[Dixonk]

It's all about the battery. A motor will take as much as the battery can provide, until it get's too hot. Get the best battery you can afford and a cheap kit, then you have an upgrade path, if you decide to let them have more power later. If you have steep technical climbs where you need to ride slowly,, the mid drive is the way to go. It will also require more pedaling, so good for fitness.

Is there no difference between a 250-750watt hub motor?
Not much price difference between the different wattages.
We rather have headroom than not.

Thanks.

 

[E-HP]

Is there no difference between a 250-750watt hub motor?
Not much price difference between the different wattages.
We rather have headroom than not.

Thanks.

What % grade are the hills and for what distance would you typically climb? A 250w and 750w hub will be different, and the 750 can run longer before it melts down so yes, the 750w will have more headroom, but both will be geared hubs, and can’t shed excess heat, so will meltdown in an extended or steep climb. In that case, get the mid drive. A direct drive hub can shed heat more quickly and with a few cc’s of Statorade for cooling can climb a lt longer and take more power without melting. Geared hubs are good for smaller hills and shorter climbs. The cheap kits I linked were direct drive. Direct drives do better in smaller wheels. I used to run 26, but am currently on 24s.

You could play with the Grin motor simulator to see how various motors perform on different grades or other conditions, including mid drives. it’s really accurate. The time to meltdown gives you a good idea if you can make it up your steepest longest hill before cooking the motor. For direct drive you can also model with or without Statorade for cooling.

Motor Simulator - Tools

Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...

ebikes.ca

PS. You can add oil and sometimes water to a geared motor for cooling, but it’s messy and will leak over time. You can model that in the simulator as well.

 

[Dixonk]

What % grade are the hills and for what distance would you typically climb? A 250w and 750w hub will be different, and the 750 can run longer before it melts down so yes, the 750w will have more headroom, but both will be geared hubs, and can’t shed excess heat, so will meltdown in an extended or steep climb. In that case, get the mid drive. A direct drive hub can shed heat more quickly and with a few cc’s of Statorade for cooling can climb a lt longer and take more power without melting. Geared hubs are good for smaller hills and shorter climbs. The cheap kits I linked were direct drive. Direct drives do better in smaller wheels. I used to run 26, but am currently on 24s.

You could play with the Grin motor simulator to see how various motors perform on different grades or other conditions, including mid drives. it’s really accurate. The time to meltdown gives you a good idea if you can make it up your steepest longest hill before cooking the motor. For direct drive you can also model with or without Statorade for cooling.

Motor Simulator - Tools

Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...

ebikes.ca

PS. You can add oil and sometimes water to a geared motor for cooling, but it’s messy and will leak over time. You can model that in the simulator as well.

Ill go in and see what the grin motor simulator is about but im going to buy the cheapest best bang for the buck, so if a 500w hub motor is 150 but a 1000w is 160, im going for the 1000w.

We will do mostly woods trails and jumps, hills are short but steep, we wont do any difficult terrain.
We dont use our bicycles for transportation and have little intention for it as of now.

I dont like the fact that middrives makes the pedals further out, we would like throttle option only too and not only using in conjunction with pedals.
But middrive seem to be the cheapest option..
Hub motors seems better for us but I dont know how to make a wheel or how much it costs for someone to make a wheel.

 

[E-HP]

If you're doing jumps, then I'd go for the tsdz2b if you can get it for the price you mentioned. The downside of the hub is weight. I could do a bunny hop with the 1000w motor, but it was difficult because of the weight. Maybe if you had rear suspension.
Get the best battery you can afford, in case you change your mind later or want to upgrade.
Note, there is an ES long running thread on the tsdz2. The main design flaw appears to be poor bottom bracket spindles, with a few (several?) accounts of them breaking. Might not be an issue with the weight of a kid.
e.g. TSDZ2 120mm Axle Broke for the 2nd time on my Fatbike

 

[Dixonk]

If you're doing jumps, then I'd go for the tsdz2b if you can get it for the price you mentioned. The downside of the hub is weight. I could do a bunny hop with the 1000w motor, but it was difficult because of the weight. Maybe if you had rear suspension.
Get the best battery you can afford, in case you change your mind later or want to upgrade.
Note, there is an ES long running thread on the tsdz2. The main design flaw appears to be poor bottom bracket spindles, with a few (several?) accounts of them breaking. Might not be an issue with the weight of a kid.
e.g. TSDZ2 120mm Axle Broke for the 2nd time on my Fatbike

Thanks a bunch for sharing your knowledge, perhaps I should look deeper into the tsbz2b, using a middrive makes it easier to change their bikes aswell.
Can they be used with throttle only for when and if you want?
ill go read the thread.

 

[qwerkus]

I'm usually not the law abiding fanatic, but I think this a very tricky scenario.: You wrote that you live in Sweden. Please keep in mind Sweden adheres to EU ebike regulations, wherein motor choices are restricted to 250 continuous watt and 25km/h max. How strictly anyone complies with it is one's own responsibility - as an adult. But in your case if you don't comply, and your kid has an accident, you're basically screwed and the kid too for the rest of her/his life.
That's why in Switzerland for an instance, Children aren't allowed on ebike until age 14 when they pass a basic form of dmv test and can ride on their own. AFAIK the EU allows Children ebikes, but only within the aforementioned limits.