My first ebike project

[Jo.qc]

Hi guy's, I'm in process of designing and building myself a ebike. This is my first ebike build. I've built a electric go kart for kids last year. https://www.youtube.com/watch?v=taNLWk31oeU

I'm looking for ideas and advices to continue my project. I'm relativly on a budget for this build. I'm in Canada and every things get real expensive with exchange rate, brakerage fee and shipping. I know some parts are maybe on the cheap side but will do for now.

Parts I want to use:
Motor: Bafang Ultra
Battery: 52V 14ah
Fork: DNM ORL 27.5 120mm travel
Rear shock: DNM RCP-2S 200 × 56 mm
Wheel: I got cheap 20in wheel with 2.80 wide tire for now but I'd like Stranger Crux XL Rim 20" with Michelin Pilot Street 80/90 - 16 48S
Brake: Sram level
Derailleur and shifter: Shimano XT
Headset: FSA Orbit Z Deep Cup 1 1/8S
Handle bar: STAY STRONG EXPERT ALUMINIUM RACE BARS 4,5" rise
Stem: BMX Stem
Modular dropout

Design:

So please let me know what you guy's think and feel free to give ideas and advices.

 

[bakaneko]

the pictures are not showing up for me. the real question is what is the purpose of the ebike and intended range? dude, i am building a 36v 500w ebike for a friend that cost $160 excluding the motor that i just want to get rid of. this same motor i went 5k miles and 160miles in one day on a $75 walmart bike. its all about purpose.

 

[E-HP]

Parts I want to use:

I see you list rear shock, but it looks like you left out what frame you'll be using.

 

[Jo.qc]

the pictures are not showing up for me. the real question is what is the purpose of the ebike and intended range? dude, i am building a 36v 500w ebike for a friend that cost $160 excluding the motor that i just want to get rid of. this same motor i went 5k miles and 160miles in one day on a $75 walmart bike. its all about purpose.

Should be better with pictures. I want to build the frame. I will use it to commute to work (17km from my home) and have fun on dirt roads and trails.

 

[flat tire]

1) your bike is possibly a little too small
2) your bike is way overbuilt for a bafang
3) your wheels are too small for riding offroad

 

[Hummina Shadeeba]

I like the design. I like the little wheels even. But the position of the rider isn’t good and if the bike is going to be so small and that person there represents ur real dimensions at least set the seat way back. The seat also has an angle with nose pointing down which I see often but doesn’t make for a comfortable position
It really is too small a bike though and u can’t extend ur legs when pedaling with a non-adjustable seat. Maybe since the seat support is long and angeled you could just push the seat back or getting a longer one.

 

[Jo.qc]

1) your bike is possibly a little too small
2) your bike is way overbuilt for a bafang
3) your wheels are too small for riding offroad

1) In wich way you think it's too small. I use dimensions from my Giant escape bike. I want the seat lower to be abe to stay on it when I stop. I know It's not optimal for pedaling but with pedal assist it should be to bad

And compare to the Luna banana

2) If you meen too strong, probably, and I rather going too strong for now then not enought. I could use thinner aluminium if I find it too strong and too heavy. What mid drive would you use?

3) I don't want to go with 26in or bigger wheels, I don't like the look of it and I find nothing affordable between 20 and 26 wheels. I like the fact i can put scooter tires on BMX wheels with the 20in wheel. If you have affordable wheels choices in 22 or 24 in, I will for sur look into it. For now I already got 20 wheels I will start with.

 

[Hummina Shadeeba]

I see those scooters around that u have ur bike superimposed over with the low non-adjustable bench seats and they work ok I think because they’re level and you can slide back on it if ur taller. Ur bike seat on the regular bike is a lot higher. If u don’t plan to pedal much it looks pretty good.

 

[flat tire]

I would use CYC X1 pro with at least 26" wheels if not 29". Bigger wheels are much much nicer offroad and will hold up just fine at these speeds and power levels.

The low seat would work better with pegs. It will be a disadvantage all the time with pedals except for when you need to stand and move around.

 

[Jo.qc]

For pedaling, I don't need it to be as easy as a normal bike. I just want to complain with regulation to go on bike path, pedal it without to much hassle if the battery is empty and get a little more range. If I really want to pedal I will use my normal bike.

It will mostly be used to commute to work on roads with pedal assist and as a toy to mess around sometimes. I don't need it to be as good as a mountain bike offroad.

For the seat I rather compromise on the pedaling effectiness then having to get off the seat everytime I stop.

The suspension will be more for comfort rather then anything else

I will look more into the CYC motors. But I liked the fact that I don't need to put a buttom bracket on my frame with the Bafang ultra and just weld the bracket directly to my frame.

 

[Grantmac]

If I was designing from scratch I would look at parallel rather than a serial mid-drive like LMX and Boxxbike use.

Also I echo the advice for larger wheels. 20" just won't cut it on any actual off-road stuff.

 

[Jo.qc]

I don't really like the look of it with 26in wheel

 

[Hummina Shadeeba]

Looks dope/fly w the little wheels! Any difficulty offroad will just make u better. Never seen a trials bike w 26”

 

[Grantmac]

Trials bikes run 21" moto tires up front which are similar to a 27.5 bicycle wheels.

It would be a shame to build something that could be good but gets let down by lack of travel and inability to roll over the smallest of obstacles.

 

[Hummina Shadeeba]

I don’t know why u say 27.5 wheel, the trials wheels I see are all smaller than a 26”. I like riding off-road w rigid fork n rear and even thin slicks these days. Off-road is a broad category. This with the bench seat and slicks looks good to me if not really going to pedal it

 

[Grantmac]

You're talking trials bicycle, although they also use 26" for the "big wheel" class.

I'm talking trials motorcycle which is much more applicable to a heavy ebike.

 

[Jo.qc]

The bike should weight around 50 pounds. I will continue my reflexion on the wheels choice. I think I'll check how diffrent wheels size would affect the bike geometry. But keeping the 20in wheels I already have would save me a bunch of money I rather not spend before testing the bike.

I was also inspired by the super moto Sur Ron wich have 17in moto wheel that are almost the same size as 20" bike wheels I have. Is the Sur-on super moto bad on bump ?

Compare to Sur Ron super moto:

 

[Grantmac]

The Supermoto is designed for pavement.

Also you need to look at much more fork travel if offroad is the goal.

50# is extremely optimistic. Think 70-75# realistically.

 

[Jo.qc]

The Supermoto is designed for pavement.

Also you need to look at much more fork travel if offroad is the goal.

50# is extremely optimistic. Think 70-75# realistically.

So I should be ok cause I will almost only use it on pavement and not offroad. :wink:

I will have 120mm of travel at the front and rear

15pounds for the motor
7pounds for the battery
12-14pounds for the frame
and all the other stuff so yeah probably a bit above 50pounds but not that far

 

[Grantmac]

I didn't realize you were building a scooter, disregard my comments.