Front or Rear Drive??

Do you have a front hub motor, a rear hub motor or are you rocking the double?

  • Front Hub Motor

    Votes: 37 29.1%
  • Rear Hub Motor

    Votes: 77 60.6%
  • Front and Rear Hub Motors

    Votes: 13 10.2%

  • Total voters
    127

phorbin

10 mW
Joined
Mar 17, 2009
Messages
22
Location
Scranton, PA
I am still deciding on which to go with for my first eBike. I am leaning towards the rear hub motor setup. If you got a good argument for either way lets hear it.
 
Rear wheel drive FTW!

Real wheel drive has a bunch of advantages. The first is the cool factor. Having a big hub in the front just looks wrong. But on a more practicle side, there is the efficancy issue to wory about. as you ride, you move the front wheel back and forth in small amounts to maintain balance. If you draw a straight line down your path, you would see that the front wheel is constantly crossing that line by small amounts. The back wheel, however, tracks behind, and would continue on with little movement from that line. If you take the line your front wheel travels and stretched it out, the average rider's would be 5% more. This is one of the biggest reasons why quality speedometers are measured from the rear wheel despite the need for extra wire. For an Ebike, it means the motor has to drive 5% farther to make the bike cover the same distance.

Have you ever lost traction on the front wheel of a bike? Most kids learn how to skid therte rear tire within months of learning to ride, and sidewalks and streets around schools are in a constant state of disfigurment with skidmarks from kisd powersliding and skidding there bikes around for fun. On a rear wheel, its easy to controll a skid, as the skidding wheel is trailing, and you still have the ability to steer. Skid on a front wheel, though, and you loose all controll. since the front wheel is also the primary means of balance, and since gravity is conspiring against you at 9meters a second squared, the result of most skids is usualy a quick meeting with the street, or at the very least brown shorts. :shock:
Having the power in the front wheel using part of your traction as a means of propulsion means you are closer to the limit of traction all the time. Having the mass of the motor also means you'll have more mass and momentum to deal with to try to correct any problem.

And its harder to ride up curbs.
And it's harder to pull the wheel up or light for cruising over drains, railroad tracks, sticks in the road, ect.
And it's hard to lift the front wheel into a bikerack
And... the list goes on.
And then there are all the dangers associated with front fork failures and losing wheels. this post is turning into a chapter. I'll leave that for someone else.
 
That was a great summary for rear wheel hub motors from Drunkskunk. Just for balance, I'll list a few things in favor of a front wheel hub motor.

Much simpler to install
Better weight distribution
Less spoke breakage issues
no unintentional wheelies

Just for the record, all of my hub motors have been either on the front wheel or on a trailer. I am not into high speeds, have only had bikes with non-suspension steel forks, and prefer recumbents where lifting the front wheel over objects doesn't work anyway.
 
I prefer a rear. Stealthier and it doesn't throw everything off when going over a bump. Not that much harder to install, either. Generally the only difference is that you have to move the chain off the sprocket and back.

Plus the part about the screwing up of the front forks.
 
I have three rear motors two on bikes and one yet to be built. I also have one front motor, which will go on a steel forked trike. I have used aluminum frames on both my current builds and have at least front suspension on both so do not want it messed up. I do not want a front motor problem as they can be extremely damaging to the body to say the least. I also believe that with lighter weight riders and low to mid powered front motors on steel forks few should have problems. So long, as the bike is built and maintained properly.
 
I prefer front wheel drive. After running a rearwheel bike for a couple of years I tried a front drive system. It has better balance and tends to corner on gravel much better. Both the front and rear wheel bikes have front suspension which helps with control. I have tried batteries low on paniers and on top of the rear rack and find the difference in control is minimal with front wheel drive. I am not one to slide / skid tires so maybe if this is a priority then the rear wheel may be an advantage. Most of my rides are on bike trails - some with hairbone turns - and I find that with the front wheel drive I do not end up under a bush as much. I like to ride with a fairly large battery = 48v - 20ah lifepower which requires a stiff but good shock absorbing rear wheel / tire with no rear wheel suspension. As far as grip - I find that climbing a hill just requires leaning forward except when also going over a bump - I used to loose control of the front wheel when using rear wheel drive. Off the line is better with rear wheel drive - but this is where I do my pedalling and leaning forward. I normally use a backpack for carrying my extras but slap on the paniers when it gets too hot.
 
Show me a marketable motorcycle or scooter with front wheel drive.

Batteries for ebikes are easiest carried on a rear rack but upset the balance of a bicycle with a rear hub motor. Most people running rear motors don't carry their batteries on the fork.
A frame bag in the main triangle or box mounted battery along the seat tube or down tube rides better than a rear rack or fork mounted battery.

For a snow bike, I'd opt for a front hub motor, batteries carried forward in the main triangle and a saddle low enough to drag my feet.
 
I've got both but they are totally different machines. A big heavy cruiser with a rear motor and batteries in the triangle. It is good on dirt, gravel. And a front motor on a recumbent with batts in the middle. It is balanced well for the street.
 
Front wheel drive on a bike may look odd to some, but for balance, it's the best by far.

Changing spokes on a rear wheel is arguably the worst job on a bike, yet folks do it routinely with rear drive bikes, no thank you.

6,000 kms and still no broken spokes on my 24 spoke rear wheel. Must be the quality of spokes, because they are definately not thick.
 
I've built a lot of electric bikes. It's easier to setup a typical FWD system and works ok for low power setups.

For high power a RWD system is better. It's also better for off road, riding in the rain or snow, wet grass or anywhere else traction becomes an issue.

As for the weight/balance thing, the problem is most folks doing a homebrew project put their batteries in the wrong place, ie in panniers or on a rear cargo rack. It takes a little more effort but the batteries should be rigidly mounted to the frame of a bike. I've tried many places on typical bike frames but like best putting them above or on each side of the lower frame tube that runs from the head tube to the bottom bracket. This gives great handling and leaves the rear rack and panniers empty for picking up groceries or carrying stuff like a charger for extended rides.

I have an inexpensive and simple way to house and mount batteries. I make battery boxes out of coroplast (corrugated plastic - campaign sign material) often harvestable in early November and sometimes in March around here. I make mounting brackets out of aluminum flats, usually a 1/8" by 1" by 8' can be cut and bent into pieces to make a complete mount. The pieces can be pop riveted or welded together. I wrap my frame tubes with old inner tube and electrical tape before installing a battery bracket to protect the paint. Brackets can be fastened to the frame with hose clamps and/or cable ties. Sometimes they can be ligned up and drilled to use the screw holes of water bottle mounts but those aren't needed and alone they are insufficient.
 
SpeedEBikes said:
. Sometimes they can be ligned up and drilled to use the screw holes of water bottle mounts but those aren't needed and alone they are insufficient.

I'd like to see some pics if you have any. The bike in your avatar looks light.
 
Reasons I chose a front motor:

90% of flats and 100% of broken spokes have happened on my rear wheels.

Better weight distribution when using a rear battery.

Ability to retain present shifter and easily use 8 or 9 speeds (and yeah I use my gears).

Front motor is simpler to install.

That pretty much sums up why I chose a front motor. The traction issue isn't a concern for me since I use a low power motor and ride on the street. My Bafang can spin the front tire when I take off from a stop because the front wheel gets unloaded but that's the only time it's a concern. Also with a low power motor the strength of the dropouts isn't as big of a deal. If I were building a high power ebike of course I would choose rear...or 2wd.

-R
 
Would another advantage of front motors be that they convey more inertia to the steering moment, so that the bike is less twitchy steeringwise, in relation to the power conferred? On my small, 20 inch and 16 inch wheeled bikes I definitely found the steering to be much less twitchy after the motors were installed in the front wheels. Perhaps this is just a rake/trail issue with those geometries, which responded well to this improvement?
 
Russell said:
Reasons I chose a front motor:

90% of flats and 100% of broken spokes have happened on my rear wheels.


-R


Good arguement.

I voted rear hub because I carry and or drag over 180lbs on my bike some days including batteries. Even now the steel front forks are taking on a lot when braking.

Many complain about having to use torque arms on front hubs and some do need torque arms on rear hubs. My golden just sits in there using the supplied torque washers and carries ship loads of cargo and not once slipped. My wife had the aluminium bike tampered with in town and some arse undid the bolts and a few other bits, the rear wheel was almost falling off by the time I got out there. She road 2kms with trailer and shopping and still no spun wheel.

Ive had my share of blown tires and broken spokes. I remedy this by not pumping my back tire up to max (leaving it shy of about 5 psi) and using thicker gauge spokes but not having them tense. They are quite lose. No broken spokes or flats since. No heavy packs on the back like Zoot says with the rear hubs.

Where there is an E-bike there is a problem, where there is a problem there is a solution, only experience will dictate how you manage in the end.

On one bike I have an alloy deep well rim and use 12 gauge and on another wheel not in use ATM I have a steel rim with 13 gauge spokes. The 12 gauge spokes on the alloy rim is superior IMO.
 
My bad! 180 lbs on my rear hub was an unfair estimate and an insult to my E-bike and rear hub.

I added it up and it's more like 300 lbs. Bike rider me 147 lbs, SLA batts 66 lbs, shopping 90 lbs and or maybe even another person.
 
I use both, singularly and together.
 
I only chose the rear b/c I wanted a super stealth look. My next e-bike would have a front mounted one though so I can take advantage of having a rear internal gear hub. At least that's the thought. We'll see. That may not be for awhile. I'm having lots of fun with the current Mini Might on my (used to be sister's) Trek 800.
 
Russell said:
Reasons I chose a front motor:

90% of flats and 100% of broken spokes have happened on my rear wheels.


Ability to retain present shifter and easily use 8 or 9 speeds (and yeah I use my gears).

Front motor is simpler to install.
-R

I ordered a 9 speeds suntour cassette for only 20 euro's from my local bike shop so not be able to use 9 or even 10 speed isn't an issue.

Broken spokes are caused by low quality rims or not properly spoked wheels. Or you are just really really heavy and i mean like well over 300 pounds. Any decent quality wheel shouldn't lose any spokes just by riding.
If your spokes break regularly i seriously suggest looking for a stronger wheel..
 
I have front wheel drive. I would recommend rear wheel for faster and stronger speeds unless you want to spend time balancing or wrestling with the handlebars. The front wheel hub creates a nice distribution of weight, however.
 
Got one of each ( so I did not reply to the poll ).

First build was front wheel -- my thinking was simplicity of installation. That was 3,000 miles ago and no complaints except for jumping curbs.

Second build was for my wife -- one consideration was the ability to take the bike on the Max (the light rail here in town). The trains have hooks where folks lift up their bikes and hang them from the front wheels for the train ride. With a rear motor (and battery) it's easy to up-end the bike and then lift it to the hook for those last few inches. On my FW bike, it ain't all that easy.

But with the FWD, I like the surprised faces when I do a burnout......
 
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