Help with my first ebike build

[delboy55555]

So I've been reading this forum and also ES and trying to decide what to fit to my bike and convert it to electric.

The bike is a 2009 specialized rockhopper mtb with 26" wheels front suspension and disc brakes;

I want it mainly for commuting on the roads to work but still with a little off road/trail riding ability. I have a few steep hills where I live to get up but don't mind pedalling a bit. It would be nice not to be sweating before i get to work though. I weigh about 90kg.

After initially thinking of going for the gsm mid drive setup, i'm thinking instead of going for a q128c motor - 36v 201rpm; https://bmsbattery.com/ebike-kit/769-q128c-135mm-500w-rear-driving-ebike-hub-motor-wheel-ebike-kit.html#/213-rpm-201/42-voltage-36v
I think the q128c setup will be a bit more stealth, a cleaner install and I won't have to worry about changing gear under load like you do with a mid drive, is this correct?

I'm thinking of using the 36v version with a 48v 11.6ah battery for more top speed. specifically this one as it comes with controller and lcd display;
https://bmsbattery.com/ebike-battery/680-48v116ah-bottle-09-panasonic-battery-pack-battery.html

Also planning on buying torque support arms.

I'm wondering if i will be able to use this with my existing 9 speed cassette and disc brake and swapping them over to the new wheel? Would it fit? Does my plan seem decent?

 

[Swytch Bike]

Hi Delboy

Your plan sounds sensible - the q128c will probably suit your need and be easier to fit than a mid drive kit. However the mid-drive kits are noticably better for hill climbing and the changing gear under load thing isn't really a problem when you get used to it . Worth reconsidering the mid-drive if the hill climbing is an important reason for wanting the kit

Also - have you read up about over-volting? Using a 48V battery with a 36V kit will potentially have side effects and so it's important to be sure you know what you're doing before you go this route. A common reason to overvolt is to seek a higher speed, but it's much preferable to just buy a motor that is configured to the right speed and that matches your battery and controller voltage

 

[delboy55555]

Hi Delboy

Your plan sounds sensible - the q128c will probably suit your need and be easier to fit than a mid drive kit. However the mid-drive kits are noticably better for hill climbing and the changing gear under load thing isn't really a problem when you get used to it . Worth reconsidering the mid-drive if the hill climbing is an important reason for wanting the kit

Also - have you read up about over-volting? Using a 48V battery with a 36V kit will potentially have side effects and so it's important to be sure you know what you're doing before you go this route. A common reason to overvolt is to seek a higher speed, but it's much preferable to just buy a motor that is configured to the right speed and that matches your battery and controller voltage

Hill climbing is an important reason for me, the main reason really. I don't mind pedalling on the flat its the hills that kill me,and put me off using the bike more. There are some long fairly steep streches where i live maybe 1 in 8 gradient and some crazy steep hills up to 1 in 3.5! To be fair I could avoid those completely and take a different route but it would be nice to have the ability just to show off and to be able to have some fun now and then!
The ability to climb super steep hills is a luxury I don't really need though.

I do like the excercise at times but for commuting to work I just don't want to be sweating before I even start a hard days work! I have looked into the bafang mid drives and the latest gsm, seems to be some issues with motor reliability/cassette and chainwear and also the alignment of pedals causing some people issues with their knees. I have a dodgy right knee so this is a concern for me. Maybe it isn't a valid one I just don't know!
Yes I have read up on overvolting , it was the reason I decided to try a 48v battery with a 36v motor, as the motor I would be buying has a low speed winding of 201rpm and with a 26" wheel I think the top speed would be too low so apparently overvolting to 48v would give a 33% increase in speed and take me to around 22mph which is enough I think...

 

[delboy55555]

I should add I will be hauling the weight of my bike, plus myself at 90+kg and then the kit and battery and also a set of full panniers and a backpack at times too. Reliabilty is the most important thing over speed since this will be my main form of transport (no drivers licence.)

 

[1boris]

I would recomand the Bafang bbs 02 750W from EM3EV.COM with the new infenion controller.Nothing beats it at the moment if you ask me.You have easily 50 kmh top speed.And crazy steep hills are no problem

 

[mfj197]

And I'd recommend the 250w BBS01. Will get up anything using the gears, is reliable, and is nominally legal (although will pack at near 600w).

Mid drives do have a few issues with changing great under drive if using high power levels. I personally don't have a problem as I use lower assistance levels because I enjoy cycling. Mid drives have amazing flexibility though, with Michael the ability to get up any hill you put in front of them but still drive along powerfully on the flat.

I have reprogrammed my BBS01 though...

Michael

 

[delboy55555]

Hmm I'd love a bbs02 its a bit more pricy and a bit more of a gamble when trying to be stealth. I may end up going for one though I need to save a bit more money first. If the bbs01 really can get me up good hills without sweating I may get one of them instead. Its just those geared hub motors sound really good too and are cheaper so its hard to decide!.

 

[trex]

...
Its just those geared hub motors sound really good too and are cheaper so its hard to decide!.

the woosh GSM is just as neat and easy to fit as a BBS01 and does not cost more than a hub kit. GSM + 11.6AH battery £499, with 15AH HL (case 08) battery £549.

 

[1boris]

I think the bbs02 is stealth.especially if your bike is black like the motor.And it is very quiet and reliable.I wouldnt go for a 250w bbs personally,especially if it was my main form for transport.not powerfull enough imo.The bbs 750w is only 5mm wider so it looks exactly the same.And the price diffrence arent that much,depending on where you buy it.Em3ev sell them with a push button for cutting motor power when changing gears.When you get use to it,gear change is very smooth.Also he is known for standing behind his products if something goes wrong.But the q128H motor is also very nice.But maybe for longer hills it has to high rpm.I have not tried the q128C but a 36v 200 rpm motor vith a 48v battery with an 18/20 amp inbuild controller.I belive would be a perfect match.And gear changing with a hub motor is very smooth and easy.Maybe the bafang bbs 250w is powerfull enough for you,
Its not easy to choose.But the only thing I am sure about is that you would not be dissapointed with a bafang 750w.And I also have dodgy knees.

 

[Nealh]

The problem with 750w is that it has so much power that after reasonable use any 250/350w would always feel or appear to be inferior. I find the BBS01 @ 36v more than adequate for mtb offroad and is very good on the road.