Back Wheel Motor vs Front

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adamsavage79
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Back Wheel Motor vs Front

Post by adamsavage79 » Dec 15, 2017 11:27 pm

I've noticed that vast majority of the pictures I see of Ebikes, have rear end motor vs front. I'm thinking of getting a rear motor that works with disc brakes, from Golden Motor. I find it's getting harder to find a good frame that supports V brakes, and I find the front motor is a pain when dealing with forks, and such. The only advantage is that it spreads the weight of the kit out.

So my question is, why do so many go with a Back Wheel motor vs front ?

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Re: Back Wheel Motor vs Front

Post by wesnewell » Dec 16, 2017 12:13 am

Better traction since most of the weight is on the rear wheel even without a motor. Stronger than front mount. If the rear wheel breaks you won't do a face plant on the ground like can happen if a front wheel comes off. All in all it's just safer in all riding conditions.
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adamsavage79
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Re: Back Wheel Motor vs Front

Post by adamsavage79 » Dec 16, 2017 1:11 am

Some valid reasons for the rear wheel motor. I would of never thought about clearance for the back disc brake. I know I have clearance issuses with my fronk fork and nut..which is part of the reason why I want to get away from front end drive. What is intresting though, about both front and back, is the common thing I've noticed, is that they say they are rated for 45kph, and the motor goes up to 1,000 watts. I was told mine is 500 watts, and I've reached speeds close to 55 kph, mind you this was with slicks, and I was pedaling hard. I could hit 60 doing the same thing going down a hill. On average with knobby tires, I go about 50 kph.

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Re: Back Wheel Motor vs Front

Post by tomjasz » Dec 16, 2017 1:17 am

Since i only ride my front drive bike on flat city streets! I find it my favored ride. Flat foot comfort frame, easily 27mph. Easiest build, and bike to maintain. I have a rear drive too, but find no advantage for city riding on flat streets.
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Re: Back Wheel Motor vs Front

Post by amberwolf » Dec 16, 2017 1:49 am

Motor ratings, winding versions, tires, etc., are a whole other set of discussions that have also happened lots of times. :)

Power ratings of motors...some are about right, some are underrated, some are overrated, and it also depends on who's giving you the rating: manufacturer (probably about right), seller (possibly overrated), etc. Basically has to do with heat dissipation ability.

Speed ratings...those (should) depend on the winding, which means they are usually listed as a certain speed for a certain wheel diameter at a certain voltage battery pack for a certain winding of a motor.


You might want to go to http://ebikes.ca/simulator and mess around with it.

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Re: Back Wheel Motor vs Front

Post by adamsavage79 » Dec 16, 2017 1:59 am

That's a neat thing to play around with. I had no idea the controller could play such a big role in your range. This would explain why I noticed about a 5km reduction in range this summer. What changed, was I had a different controller.

I typically don't go the max speed the motor can go, because I worry about it getting too hot and mostly of how much of the battery will get drained from going that fast.

The rated speed of the motor's I have seen, are a little faster than what I like to cruise at.

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Re: Back Wheel Motor vs Front

Post by dogman dan » Dec 16, 2017 7:55 am

Traction is the big reason to go rear, especially if you ride any dirt, even just a short driveway gets tricky with front hubs.

But if you are good enough a rider, you can of course ride anything, anywhere, anytime.

Major reasons to go front are trikes that can only use a front hub( or mid drive of course) and similarly bikes with exotic rear wheels. This can be simply a bike with no other brakes than a rear coaster brake, or a internal gear hub, shaft drive, or whatever weird shit the bike industry dreamed up over the years.

I commuted with front hub for 5 years, in a dry climate, and it worked fine. The front hub let me keep a 9 speed gear in back, with a 10 tooth high gear. I also raced at 50 mph with a front hub, But right now, I have three front hubs in my garage, gathering dust. I'm less hesitant to take a dirt road short cut now.

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Re: Back Wheel Motor vs Front

Post by Chalo » Dec 18, 2017 1:35 am

Hub motor wheels are weaker than conventional front wheels, like for like. The front wheel's job is easier than the rear wheel's. That's simple. Put the weakness where it's best tolerated.

Front wheel motor plus rear wheel pedal drive is two wheel drive. That's more traction available for driving.

If you have wheelie-making power available, then use a rear wheel motor. If your motor power is the same scale as pedal power, it makes sense to put the motor in front. Cheaper, simpler, easier.
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Re: Back Wheel Motor vs Front

Post by Samson » Dec 18, 2017 8:41 am

A front wheel drive makes more sense from the point of view of distributing the weight a bit better at least for normal flat roads. I used a front drive for a year and was happy with it until I started walking the bike up a winding staircase down a cliff face which had a bike trough. With the bike in the trough I would walk beside it on the stairs and use light throttle to drive the bike. With the front wheel drive the wheel would spin in the slippery metal trough, with rear wheel drive weight transfer prevented slippage allowing the bike to propel itself making it easier for me. On a few occasions I have had to walk the bike up a steep rough trail and the rear wheel drive allowed considerable assist whereas the front wheel drive would slip. My bikes are low powered road bikes with small gear motors. If I did not have hills and the staircase I would go with front wheel drive. Tire repair is a bit easier with a motor on the front also.

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Re: Back Wheel Motor vs Front

Post by docw009 » Dec 18, 2017 4:35 pm

I chose rear wheel drive to avoid the OP's problem with snapped forks.

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Re: Back Wheel Motor vs Front

Post by chvidgov.bc.ca » Dec 18, 2017 6:35 pm

I'm a small bike guy, preferring small geared hub motors like Cute100 and MXUS, after building many heavier ebikes with 9C and Crystalyte. I like the motor on the front, as the battery on the back with the motor on the front gives better weight distribution on the bike. And I like the 2wheel drive. Downside is risk in wet road conditions while accelerating on wet leaves etc. I've had these smaller motors up some good logging roads without any issues other than I have to "stand over" the bars more on steep sections to get better traction out of the front wheel. Easier to build and maintain as well. Always insist on chromolly forks and torque arms, both sides, no matter what motor. I still use a rear 9C on my recumbent trike, which is awesome too. Its all good. A heavy motor on the back with a big enough battery with a C rating able to support the amperage that the big motors need is pretty ungainly, especially if you wish to have gear along in panniers.

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Re: Back Wheel Motor vs Front

Post by dogman dan » Dec 19, 2017 7:58 am

No particular traction problems with weaker motors, including dirt as you have found. And no fork problems with steel forks.

But I got tired of excess wear on my front tire when I ran 48v/1000w on the front wheel. I had run 36v for some time, and no real problems with that, and did ride dirt with them. But when I got a 48v battery, the tire started spinning more than I'd prefer on the take offs, even dry, clean road. Tons of spin on dirt, sandy road, or wet. So that is the main reason I don't run any front hubs anymore. I went to nothing but 48v or more, years ago. I could of course, have given less throttle, but heh heh, tell that to my right hand.

Right now my battery is 65v, and while I ride 18 mph pulling 300w a lot, I do love to have good rear traction and 1500-2500w when I take off from a stop. And sometimes, 35 mph cruise to get a dangerous spot over with, keeping up with cars for a few blocks on a 4 lane road.

I could do this front hub. I've raced 50 mph with over 4000w with front hub. Traction was an issue, and you had to be very careful with the throttle on that bike. Power drifting a front hub on asphalt is quite a trip, including quite a few trips to kiss the pavement learning the trick.

But,,, If I did not live in the mountains, and still ran 36v, there would be no particular reason to want rear hub on a street ride. Low power on the front wheel of a coaster brake beach cruiser would work fine. I just needed, or at least wanted a lot more power to ride up mountains towing trailers, or just the hill to get home from Walmart loaded.

My dirt bikes, they will always be rear hub. They are all 1000w or more. For traction, and for wheelies when you need to pop over a log or huge rock. Front hub on dirt sucks, except for learning to power drift that front hub before transferring to paved drift.

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