Newbie front hub motor

Sweeparound

New Member
Region
Australia
Hi new to electric biking thinking about mounting a front hub motor on one of my hybrid road bikes. I have a bike with a steel front fork and another with aluminium front fork. Which fork would be better to mount the motor on both are non telescopic and have 700c rims. Is the front hub a safe drive. I will mainly be using it on bitumen and paved areas. I am 72yrs old so I am not interested in riding rough terrain. I have a few short hills only climbing 100ft or so. Both bikes have 24speed Shimano gears and are aluminium framed. What are the plusses and minuses of front wheel drive.
 

harryS

Well-Known Member
The obvious answer is use the steel fork, but sometimes a given alloy front fork has a wider/stronger axle mount than a steel one. I have converted two bikes to front wheel drive, with 250W and 500W geared motors, 4.5 and 7.5 pounds. Also have experience with rear motors and one mid drive. For riding on pavement. at bicycle speeds (10-16 mph), FWD seems perfectly normal to me. Sometimes, i'll get some wheel slip up front on wet surfaces when starting out.

Now if you are buying one of them $199 1500W, 12-15 pound, monster hubs to cruise at 45 km/hour, I have no experience with them.

This is a cruiser bike, alloy frame with a steel fork and a Bafang BPM motor on the front wheel. I'm running it on a 36V battery with a 20A controller. It might do 20 mph on throttle, but I get my kicks crusing along at 12 mph, with the high handlebars, and listening to music.

IMG_1456-1-2.JPG
 
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mschwett

Well-Known Member
Region
USA
minuses:
motor is not where most of the weight is - especially uphill
motor can't take advantage of gearing
front wheel becomes much harder to remove / replace
can have a strange torque steering effect
front fork needs to be carefully designed for the load

pluses:
very simple design, can use completely traditional bottom bracket, drivetrain, rear wheel
two wheel drive - if you are also pedaling, possible to distribute power similarly to weight
motor is fully independent from bike drivetrain, can go even with a broken chain

my city/commuter e-bike has a front hub motor, 500w. it's nowhere near as bad from a handling standpoint as many say, and i ride it up very steep hills. but i do not ride in the rain, and i'm relatively large and happy to put weight on the bars and pedal hard.
 

PedalUma

Well-Known Member
Region
USA
Hi new to electric biking thinking about mounting a front hub motor on one of my hybrid road bikes. I have a bike with a steel front fork and another with aluminium front fork. Which fork would be better to mount the motor on both are non telescopic and have 700c rims. Is the front hub a safe drive. I will mainly be using it on bitumen and paved areas. I am 72yrs old so I am not interested in riding rough terrain. I have a few short hills only climbing 100ft or so. Both bikes have 24speed Shimano gears and are aluminium framed. What are the plusses and minuses of front wheel drive.
Welcome! I understand that you want to convert the bike you have. Makes sense. Too many serviceable bikes end up in a landfill. It is a form of recycling, cycling recycling. Also front hub-wheels are easy to install and inexpensive. I see the attraction there as well. Next draw backs: Front hub motors are not efficient, in fact hub motors that do not have Shift Able gears are inefficient and will overheat, dying on a sustained climb. Weight is out at one end of the bike - you would not design a boat like that. Weight is rotational - hard to spin up and hard to spin down to slow or stop. Weight is in the steering. Torque is applied to one side of the fork differently than the other - can cause torque steer. On slippery surfaces the steering wheel will spinout so that steering is impossible - not a good thing. On this final point, if 99.5% of the time you are on the clean dry tarmac fine, but it is the .5% that will cause the crash. It could be a spill you don't see.
That said if you want to go 17Kph with the steel fork and not sweat too much you will be fine. Use torque arms on both sides.
 

indianajo

Well-Known Member
I ride a front hub motor. No problem. 1000 watts. Picture of bike left but avatar editor took off the front hub motor. Short hill climbing is ideal, but climbing slowly 1000' in 30 minutes will overheat a geared hub motor.
Don't power on ice, wet or muddy steel plates or grates, slick or wet wood bridge decks, wet or muddy rock. Pedal in these circumstances. I do ride in heavy rain & snow as long as there is no glare ice or ice ridges piled up by the city trucks.
I put slack in my wires to the front motor, so I can change the front tube without unwiring. I just have to cut and replace a couple of tie wraps. I turn the bike upside down on handlebars & seat. When I had a display, I built a mount for it so I could swing it down for tire chain & shifter maintenance. The slack lets me lay the wheel on the ground as normally.
I don't feel torque steer on regular traction surfaces. I find my bike falls over from the kickstand if the hub motor & battery don't hold down the front. I hated the rear hub motor, that plus panniers plus tools water etc was unbalanced as was, even before I put the groceries in the bags. Had trouble dragging the rear hub motor out of the garage over the step.
Use a steel fork, no suspension. My bike is aluminum frame, steel fork. Use a torque arm supported by a real clamp, not $.50 worm hose clamp. I make 4" long torque arms out of bed frame rail, and make a clamp out of strips of box fan shell.
My motor will drag 160 lb me, 20 lb of tools lights tubes water, 80 lb of cargo, up 15% grades. It will start without help from feet on that grade. With 32:32 low sprocket I can pedal 330 lb gross up a 15% grade without the motor working. (heavy rain stops the throttle sometimes).
Don't try to climb edges at small angles. Unpowered bikes can fall over in this situation, but powered front wheel will jerk on your hands if you do that. 30 deg or greater to climb edges. My edges are ruts in the grass driveway at my summer camp.
Another big plus, you can maintain the 8 speed rear cluster with a front hub motor. When I had a rear hub motor, 7 speed cluster was all that would fit and nobody every stocked one with 32 and 11 sprockets. 28 is max & 13 min I could buy of 7 speed freewheel.
I'm age 71. Keep enjoying the outdoors & exercise.
 
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john peck

Well-Known Member
Hi new to electric biking thinking about mounting a front hub motor on one of my hybrid road bikes. I have a bike with a steel front fork and another with aluminium front fork. Which fork would be better to mount the motor on both are non telescopic and have 700c rims. Is the front hub a safe drive. I will mainly be using it on bitumen and paved areas. I am 72yrs old so I am not interested in riding rough terrain. I have a few short hills only climbing 100ft or so. Both bikes have 24speed Shimano gears and are aluminium framed. What are the plusses and minuses of front wheel drive.
I´d say both are probably okay, but steel would be better for more weight & rough terrain. How many
watts & volts? Front likely will not provide much traction uphill or heavily loaded, but much easier to
install & more accessible for tire repair & other maintenance. Definitely cheaper for most kits, but
careful of low quality batteries.
 

harryS

Well-Known Member
I would add that the motor on my bike came off a defunct Uber/Jump bikeshare venture on the East Coast of the USA. It went defunct, and thousands of front wheel drive bikes were scrapped. I bought the motor from a scrapper. So before it went on my bike, it was on a red one like this.

I would also add that I've given a few of my conversions to friends/relatives, but I would not give away a front motor conversion. While I feel safe enough with mine, I would rather have anyone riding something I put together on a rear motor. For a little more work/effort/cost, there's no risk of a possible failure and face plant.
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jumper.jpg
 

harryS

Well-Known Member
Then you'll be fine with a little 250W motor and maybe a 16-17A controller. Like this one.

The KT controllers/displays have worked well for me. You won't need much battery to power this.
Mathmatically, the above combo exceeds 250W, so you might as well get a 500W kit. Maybe a little bigger motor, and the same controller.