Heat88

Is that really a good idea? It seems like a dangerous idea to me. Isn't it hard to steer? Maybe you throttle off while you're steering? What about the weight of the motor? Does that effect steering or control? There must be a good reason there aren't any front wheel drive motorcycles. But it works for cars just fine. So maybe I'm wrong.

Here's why front wheel drive on a motorcycle is a bad idea
Most of the physics are the same as a bicycle aren't they?

Duragrouch

Motorcycles have more slack head tube angles and longer fork trail than bicycles, for stability at speed. But under front drive load, that trail works in reverse and can be unstable. Cars have the same thing, caster, and if you back up the car real fast and turn the wheel a bit and take your hands off, it will slam to the end of the steering travel, whereas going forward fast and doing the same thing, the steering will stably re-center. But on a bike, with less trail, front drive can work, if the bike geometry is right. They had some problems with front drive cars experiencing torque steer, before they figured out the reasons and designed that out (going to zero spindle offset). Bike front drive also gives several advantages; a) doesn't interfere with the regular bike drivetrain, and b) going up a steep dirt hill while powering and pedaling, you have 2-wheel drive on a 2-wheel vehicle, which can almost double the tractive effort to GVW ratio, meaning fantastic traction and climbing ability. (It only doesn't double because uphill there is more weight on the back tire so more tractive effort there.)

grumpus

Actually there are - see VéloSoleX. But seriously, the weight of a front hub motor is low and close to the steering axis so its not terrible for stability, and you're in charge of the power - don't slam it on or off when you're turning.

cyccommute 

Long before the current electric bike craze my employer bought some electric bicycles and scooters. The bikes were all front wheel drive. They pulled to the left (I think) when you applied power but you got used to that. It just felt weird but wasn't a problem.

veganbikes

It is old school or found on cheap kits. I wouldn't do it. Now that e-bikes are so ubiquitous and easy to get in quality and low quality options the kit stuff especially front wheel kits is just not really as needed.

Rick

Front hub motors are not a problem unless you use a very high powered motor and have throttle control. Two wheel drive can be a benefit. look at Grin Tech. They sell high quality units by several manufacturer's. They even manufacture some themselves.

Duragrouch

The VeloSoleX, commonly known as a Solex, is an early powered bicycle or moped, powered by an engine above the front wheel and driving it, so can also easily be used as a conventional bicycle. One is pictured in the opening minute of Three Days of the Condor during opening credits, ridden by Robert Redford. Since in continuous production since 1946, I'm sure millions have been produced and used.

https://en.m.wikipedia.org/wiki/V%C3%A9loSoleX

Dan Burkhart 

I built a front hub motor bike for my wife 12 or 13 years ago and while I wouldn’t call it nimble it handles ok and she loves it.
I used a 350 watt motor. Don’t think I would want much more power up front.
The one caution I would add is that the axle must be adequately braced against rotation in the dropouts and dropouts should be regularly inspected.

2old

Agree: FME, a small front hub system is a blast both on road and off road (you need to apply weight to the front wheel for steep off road ascents). My daughter wanted an electric cruiser, so I converted my hardtail to one for her and she loves it;


I built one for her husband who is equally happy.

2old

BTW, the second picture is before the wires were cleaned up on the cruiser. I needed to remove 30" of wire from both the motor to the controller and the throttle to the controller, then "package" them in a sheath.

XxHaimBondxX

I build a fat bike with 1000w front wheel motor. It didn't cause any traction issues, but was heavy and uncomfortable to maneuver at slow speeds.

Duragrouch

I hope the motors have some sort of torque arm, like used on coaster and drum brakes, and not relying on axle flats at dropout width to resist torque.

Dan Burkhart 

You are absolutely correct. I made anti rotation mounting tabs for both sides of the wheel that fit over the axle flats and mount to the threaded bosses fore and aft of the dropout. I will grab a photo later.

2old

The torque arm is visible on my daughter's cruiser; I need to add one on the blue beast.

grumpus

Front wheel kits make more sense when you consider ease of conversion rather than desirability of FWD - there's no need to stock different hubs for different spacing and number of gears and freewheel/freehub that would be required for a rear wheel, because everything is 9/10 x 100 mm, no need to transfer freewheels or cassettes, no gear setup required. Of course that's changing, with more bikes having 15/20 x 100/110 mm front axles, and all that extra unsprung mass won't do the ride any good. Mid drive is the better option for many bikes, but that can be intimidating for users who don't have experience with the various crank and bbkt arrangements, switching to 1x gears. I've done a few mid drive conversions, currently working on a couple of RWD conversions, I would consider FWD on the tandem if I hadn't already bought a new hub for it, but maybe still. If I did fit one it would be geared and low power, so fairly small and light, because it's an assist, not a main power source.

Rick

Grinn Technologies has an all axle front motor that can be ordered to work on most all of the old and new axle types.

FBinNY 

There's no reason to not have front motor drive on a bike.

Some may object to how the added weight affects steering, but it's far less than using front b panniers which are common enough to challenge that objection.

As to motorcycles, the answer is obvious. Non-electric front wheel drive is problematic because there's no easy way to get power from a motor to a front wheel.

The reality is that there are design advantages to rear wheel drive E-bikes if starting from a blank page. OTOH there are significant front wheel drive advantages in terms of cost and simplicity, if adapting a pedal bike to E-bike.

Duragrouch

There's a rare 2WD motorcycle, Rokon, lower speed and really fat tires, and runs engine power to the front wheel. Complicated, but I heard it's pretty unstoppable until the grade is so steep it's unstable. Electric hub drive is the killer app to get 2WD dirt motorbikes, whether gas or electric for the rear drive.

A local place has for years offered electric front wheels for Bromptons, popular because it's so easily switched between powered and standard wheels.