Probably don't even have to worry about it with that low of torque.
Put it on there anyway.
250W 15A motor, 15A controller, 48V 15Ah battery with 30A BMS compatibility?
- Thread starter leakimc
- Start date
Put it on there anyway.
A steel fork with twin torque arms is safest. After that it’s just degrees of risk. Forks vary in quality, so suggesting it’s OK for no TA on an aluminum fork wouldn’t be advice you’d get on this forum. Opinions may vary on using a low powered front hub with an high quality aluminum fork, but likely not vary on whether to use a TA with a hub motor.
As an aside, I saw a pic of a “fork” once on this forum that looked like it was made of tubing, smashed flat at the end, with an axle slot cut into the flattened end. Scary. It made me realize how international this forum really is and not assume things based on descriptions without seeing them.
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You don't want to get flipped over the handlebars, use the torque arm, at least one.
I found a way to bolt it through a hole somehow. Putting one on each side will
probably require cutting all your phases and halls and installing quick connects on them all.
So like..13 connections. Pretty sure some halls don't fit through the nut holes.
I found a way to bolt it through a hole somehow. Putting one on each side will
probably require cutting all your phases and halls and installing quick connects on them all.
So like..13 connections. Pretty sure some halls don't fit through the nut holes.
Except you are not planning to have small 250W motor. You are planning to have 48V(54V when battery is fully charged) and 15A controller, which will give you 800W of input power. It is a LOT! Far to much for a front hub in my opinion. Also installing front hub on MTB is an error of judgement IMO. Go for mid drive or rear hub motor instead.
Rear hub above 350watt
Rear hub 48v 15ah and 18amp 22amp controller..
True and adjust and tighten spokes a must
Make a cardboard box the size of the battery make a cardboard box the size of the controller see where they fit best on the bike.
At that wattage you can probably get a controller and battery in the same setup low wattage.
Rear hub 48v 15ah and 18amp 22amp controller..
True and adjust and tighten spokes a must
Make a cardboard box the size of the battery make a cardboard box the size of the controller see where they fit best on the bike.
At that wattage you can probably get a controller and battery in the same setup low wattage.
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Motors rated above 250W are illegal in Europe.
There is no need to get motors above 250W anyway as power is delivered by controller, so you can have all power you want within legal limits.
Right, that's a good point. What's the significance of the 250W rating if the potential output is up to 800W? Is it about continuous power or? Also, I'm not really looking to put it on a MTB, more like a hybrid or a sturdy city-ish bike. It would mainly be used on roads and urban areas. You seem to also have a front hub motor on your hybrid (or is it a MTB?), what are your specs? Thanks for the advice!
Main difference is that 250W rated motors are legal and those above are not. You want 250W motor.
Forget word "continuous" it will only confuse you. Majority of motors rated 250W should be able to take 800W without overheating.
I have two bikes with front wheel motors and two with mid drives. Bike on my avatar is an MTB. It is OK on roads and OKish on mild off-road, but take my advice and install rear hub or mid drive. You simply don't want added weight to your fork especially when you are planning to use a lot of power.
What you want is a 48V system. You want 250W rated motor and 15W up to 20W controller. It will give you all the power you need to climb hills without effort and it will be legal. You just want rear hub or mid drive - trust me.
It is aluminum and I didn't install torque arm (I should have), but it is a low powered bike I converted for my wife to ride on tarmac easy bike trails. Completely different cup of tea to what you plan to have. My main bike is 48V mid drive with 16W controller.
This is my main bike. Motor is 48V TSDZ8. Controller set to 16A. Really it is 750W motor which was rated 250W by Tongsheng for legal reasons (I paid good money for that). 90% of time I use first level of assistance. 10% of time I use second to climb all hills I need without effort. I don't use third or fourth level. This motor has all the power I need.
It was my first conversion. Yosepower 36V 250W front wheel kit. I don't know what is the exact power (it is low - maybe 300W). I would have to open battery base to check as controller is there. It is OK, but what you really want is a bike like mine. Legal and powerful. You can use this power or not, but it is there if you need it.
Go to your local bike store and try a front motor bike and try amid drive and see the difference for yourself
It's like buying Italian shoes some are very pretty and some you can't get your feet in. And if you do get your feet in they hurt like hell. So go try the different bikes on first
It's like buying Italian shoes some are very pretty and some you can't get your feet in. And if you do get your feet in they hurt like hell. So go try the different bikes on first
If you have a choice, a rear motor is always better. It's safer, has better traction, gives better steering, makes less noise (apparent), and doesn't comromise the front suspension.
If you must use a front 250w motor, you should always use a torque arm with aluminium forks. Not all forks are suitable for a front motor. They must have inboard drop-outs otherwise the tube will run on the motor. the drop-outs must have a lot of meat around them. Some are just too weak. The problem isn't just the strength. Aluminium suffers from metal fatigue, so a drop-out could pop randomly at any time in the future when you least expect it. When that happens, you go straight over the handlebars and land on your face. I've seen that happen twice, right in front of me, which is why I say you need to be really cautious with a decision to fit a front motor.
I fitted a relatively high torque front motor once. It was a triple motor bike for a hill-climbing challenge. It worked fine with two well anchored torque arms, but when I took the wheel out to fix a puncture, both drop-outs had popped. Only the torque arms were holding the wheel in.
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Thanks for the info. Do you think changing the front fork into a steel one would be a realistic solution? If I had a 36V motor with a 15A controller + a torque arm.
It is better to reduce Amps than Volts...
I wonder why you insist on front hub conversion? Is there a reason you didn't mention before?
There is one more important thing for you to consider - torque or cadence sensor?
I’m planning to covert good quality second hand bikes into ebikes as a sort of business, and initially I figured a front hub would be the most convenient when it comes to installation and compatibility with varying bikes. It’s just an assumption based on the information I’ve gathered so far though and feel free to correct me.
Also, wouldn’t reducing the voltage also reduce the peak power of the motor? Why is it better to reduce amps?
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Just a reminder. One of the failures I saw that sent the rider over the handlebars was on a bumpy trail uphill, so the motor was running slowly with full torque, which had previously been OK, but the extra impact from a bump was enough to pop the drop-outs. In other words, if you care about your wife, you need to get on your bike, so to speak. I'll even send you one if you give me your address because I care about her.
That is very kind of you Seneagle. I really appreciate your offer. Rest assured, my wife is safe. She has completely new e-bike now. Mentioned above front wheel conversion is gathering dust in shed as my spare bike. I must find some time and energy and sell it on Ebay. Before that I will of course install torque arm.
You want to compete with the Chinese for labor and parts in building e-bikes. Sourcing quality batteries and liable for cheap Chinese products that you must guarantee because where you live is a small place.
I've seen other people lose lots of money even going to China getting a company to put his name on eBay it was a disaster he's now retired for that business with a warehouse full of bites he can't sell as they're out of date.
There's a e-bike in front of my house on the sidewalk for free no tires on the rims but the rims look good I bet the battery is dead I wouldn't touch that money pit even though it is free and looks nice.
Remember I been doing this for 15 16 years and I have a bunch of bikes and motors and controllers in my garage throttles everything. If you try and do this as a business you'll be crying.
I've seen other people lose lots of money even going to China getting a company to put his name on eBay it was a disaster he's now retired for that business with a warehouse full of bites he can't sell as they're out of date.
There's a e-bike in front of my house on the sidewalk for free no tires on the rims but the rims look good I bet the battery is dead I wouldn't touch that money pit even though it is free and looks nice.
Remember I been doing this for 15 16 years and I have a bunch of bikes and motors and controllers in my garage throttles everything. If you try and do this as a business you'll be crying.
Yeah, there's no money in converting a bike into an ebike, though I do know somebody who does just that and makes some bucks!
There's an endless supply of quality used bikes out there going for next to nothing that would make great donor bikes.
But with all those cheap ebikes that are produced an ebike conversion makes no economic sense. So all those pedal bikes get crushed. And those cheap ebikes, they get crushed too.
It's a tragedy of micro mobility, so much waste.
There's an endless supply of quality used bikes out there going for next to nothing that would make great donor bikes.
But with all those cheap ebikes that are produced an ebike conversion makes no economic sense. So all those pedal bikes get crushed. And those cheap ebikes, they get crushed too.
It's a tragedy of micro mobility, so much waste.
That is one more reason to do it right. Shortly after buying, your customers will probably sign in on a forum like this one and start asking questions:
- How to derestrict my bike?
- How to increase amps?
- Where can I buy fast charger?
...and then they will blame you is something goes wrong.
I disagree with some comments above. I think there is a gap on the market and there is a need for bike mechanics who convert bikes. Maybe not as a full time job, but as a second income.
...so good luck.
docw009
1 MW
Rear drive, geared 500W motor, 48V15Ah, 20A controller. That's about 600WH of useable power. At 25km/hour, you should approach 100 km for range on pedal assist. Should run easily to 35-40 km/hour.
No need to go overboard on battery AH. You're building this bike, and if you watch the marketplace, you can pick up a spare battery pack and be able to wire it in, if you really need to ride longer than 80km in a day, Buyers of commercial bikes don't have that kind of freedom.
Front drive is too slippery in winter. You could make it work with the right tires, but why bother. Choose rear drive now, eliminate the concern over broken fork, wheels slipping, heavier steering feel,
And noise. Some motors are quiet, but my front Bafang motor resonates thru the forks (steel). Frame is alloy. I can feel it thru the handlebar grips and pedals. I've filled the forks with expanding foam which has cut down the noise. I plan to to fill the frame next. I have two of these motors (cost $45 USD ) and both do it. My other FWD bike uses a small 250W geared motor and is pretty quiet.
No need to go overboard on battery AH. You're building this bike, and if you watch the marketplace, you can pick up a spare battery pack and be able to wire it in, if you really need to ride longer than 80km in a day, Buyers of commercial bikes don't have that kind of freedom.
Front drive is too slippery in winter. You could make it work with the right tires, but why bother. Choose rear drive now, eliminate the concern over broken fork, wheels slipping, heavier steering feel,
And noise. Some motors are quiet, but my front Bafang motor resonates thru the forks (steel). Frame is alloy. I can feel it thru the handlebar grips and pedals. I've filled the forks with expanding foam which has cut down the noise. I plan to to fill the frame next. I have two of these motors (cost $45 USD ) and both do it. My other FWD bike uses a small 250W geared motor and is pretty quiet.
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