First Build Advice

BoronLump

1 µW
Joined
May 18, 2024
Messages
2
Location
Miami, FL
Hello everyone, I am looking at building my first Ebike. Ideally I would like to keep it under $2000. I love the enduro frame builds with motorcycle seats and motorcycle tires. Here is my main inso, but I think I don't need quite the power this person is running: First Enduro Build For My Boys (14 & 12)

My requirements:
- At least 30mph max speed
- Can hold 300lbs
- At least 20 miles range throttle only around 20mph
- Easy-ish to assemble, preferably order motor already on a rim
- 20"x4" rims with motorcycle tires
- Dual suspension

I'm thinking of essentially copying almost everything from my inspo post but I don't think I need a QS205 necessarily and definitely not a 72v battery. Any frame/battery/motor/controller recommendations would be much appreciated! I'd also like to keep this bike at least semi weather-proof. Lastly, I do not need it go to 50mph or something crazy,
Thanks everyone!
 
I love the enduro frame builds with motorcycle seats and motorcycle tires.

Great! That's not a bike. If you're going to ride a moped or motorcycle, please adhere to your local requirements for those things and FFS stay out of bike lanes and paths.

I recommend using a bicycle. Just sayin'.
 
Great! That's not a bike. If you're going to ride a moped or motorcycle, please adhere to your local requirements for those things and FFS stay out of bike lanes and paths.

I recommend using a bicycle. Just sayin'.
Yes, I intend to be compliant to every local requirement.
 
https://ebikes.ca/tools/simulator.html with parameters batt=B4816_GA&wheel=20i&frame=fat&motor=MG310_STD&axis=mph&hp=0&autothrot=true&throt=95.2&mass=140

According to the simulator, you need about 400W motor power (500 W out of the battery) to go 20 mph on flat ground with a 20" 'fatbike'. I assume 4" tire width qualifies as 'fat'?
Anyways, this motor+battery+controller combination should work and get a range of 32 miles, says the simulator.

I assume this is then a US class 2 ebike (throttle, max. speed 20 mph)? So not allowed on separated (not road-adjacent) bike paths, but street legal. Just make sure your kids don't ride on the side walk either; I see that a lot here, and it seems like a recipe for disaster (and liability), especially with old people around.

With 30 mph I think you would need motor vehicle insurance and some kind of license and registration, no?
 
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I weigh about 245 pounds right now, and my fast e-bike (32+ mph on flat, no wind) uses a direct drive QS212 motor in a 26" wheel. The bike is heavy and very non-aero. I get about 50 wh/mi when I'm stomping on it mercilessly, which gets me at least 40 miles from my 44V 47Ah battery. I reckon I could double that range if I maxed out at 20 mph and limited starts and stops. My guess is that 48V 12Ah of battery would meet the criterion here, depending on how inefficient the specific tires are. More battery capacity is better in terms of how much lifespan you ask of the battery.

If you're cool with a front hub motor, you can use a "normal" 135mm rear motor for a fat front wheel. That buys you a lot more economical options than using a 170+ mm hub in the rear.
 
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