best value hub motor for mountain bike conversion

[zogthegreat]

Hi everyone!

I'm looking at converting a mountain bike to an ebike hybrid for my daughter. I already have a 48v lifepo4 battery pack to power the bike. I assume that I will also need a controller for the motor, so recommendations for that would also be appreciated.

My daughter weighs 50kg/110lbs and she is planning to use this mainly to go to school, about 5kms from where she lives, (although once she has it, she will probably go father than that!). This will be a winter project, (we live in Montreal, where winter is about 7 months!), so I have plenty of time to order parts from China if necessary.

I'm perusing the site for more information, but does anyone have any suggestions or thoughts?

Thanks!

zog

 

[2old]

Since you're in CA, look at ebikesca (Grin). They will advise you and have kits. Don't discount a front hub system. They provide a more balanced ride, are lighter and don't feel like you're riding a bike with concrete in the rear than rear hubs IMO.

 

[zogthegreat]

Hi @2old, thanks for the reply.

I have been going through the ebikes.ca website. Lot's of information there. However, I have a mailbox across the border, so shopping in the US is also an option for me.

BTW, in regard to your name, it's not the age that counts... it's the mileage! :lol:

[EDIT] Also, thanks for the tip on the front hubs, I was thinking that a rear hub was better for weight balance.

 

[Chalo]

I favor front hub motors for "low power" (legally compliant) builds. They're simple to install and least disruptive to the bike's other functions. But if your daughter's bike has a suspension fork, best limit yourself to rear hubs.

I would try to find a 250-500W geared hub motor kit with a display that allows parameter setting. You don't say how old your daughter is, but for safety or her own confidence it may be useful to limit current or top speed to something less than the maximum available. Relevant kits are available for about USD$300 at this time.

 

[zogthegreat]

Hi @Chalo, thanks for the reply.

My daughter is 17 next month, (gaaa my little girl is getting big!), so I want to keep the speed to a reasonable number. When I was that age, I tended to be somewhat stupid about things like speed, and if I am honest, my common sense was also lacking then, which is how I ended up jumping out of perfectly good airplanes and helicopters in the US Army/USAF!

The bike is a Brodie Force with a RockShox front suspension, so I guess that cancels out the front hub motor. Having said that, $300 USD seems like a reasonable price for a conversion. You wouldn't happen to have any US links would you? ebikes.ca is a nice site, but they add the "Canadian tax", i.e. adding extra costs to their product because most people in Canada don't have a US shipping address. As much as I like living in Canada, the extra 25% - 60% that Canadian retailers add to the price really sucks!

 

[Chalo]

For this project, I would be inclined to buy one of the small geared hub motors from topbikekit.com along with a battery that contains the controller inside the same case (if there's enough space to mount it).

You don't need a ton of power, so you might as well get a lightweight motor with good starting torque. Even a 7-1/2 pound Bafang geared hub motor is overkill for carrying a very light rider at modest speed. But topbikekit.com has hub motors down to about 3 pounds, with several options to choose from. Getting a battery with integrated controller reduces the amount of necessary cabling and makes it easier to find room for everything on a small bike.