Electric Bikes - Gravity & Pull vs. Push going up hill

I'm about to upgrade my bike with an ebike kit.

so my bike started out as a 8.7 kg (19.18 lb) bike, with upgrades and accessories, it's sitting pretty close to 10 kg (22.05 lb) now, and i weight in at aprox 165 lb (75 kg) give or take, the back pack i carry, is another 2 lb (almost 1 kg) in average.

This brings me to an approximate total of 86 kg or 190 lb for the overall mass / gravity.

Now we add in another 7 kg / 15 lb, from the ebike kit and it brings the bike to a total of 93 kg / 205 lb
(bike alone total 17kg / 37.5 lb)

On a bike, most of our weight is on the rear wheel, even though the center of gravity is suppose to be in the middle of the bike, or just between the 2 wheels. So my estimate is aprox 142.5 lb rides on the rear wheel, meanwhile 62.5 lb (47.5 + 15) rides on the front wheel. (assuming i go for the front wheel setup)

So, I'm trying to find out, Power to Torque wise, what is more effective when going up a hill;
- Rear wheel install = power to push forward, will be affected by gear change
- Front wheel install = power to pull forward, gears remains unchanged

Kind of like a Front wheel drive japanese car, vs a Rear wheel drive american car.

Pro of having the Front wheel install:
- uniform speed unaffected by gear change
- takes weight off the rear wheel, going up hill the weight is spread, center of gravity still relative to the middle of the bike.
- pull action

Cons:
- the front wheel tends to get the worst of most accidents, if the front wheel is out of commission, so it be as well be for the motor.
- might not pull as well, since the weight is mostly on the rear, so it might be losing power to torque. But i can always lean forward to transfer more weight to the front.

Pro of having a rear wheel install:
- push action.
- more pressure exerted on the rear wheel, more power to torque ratio.

Cons:
- rear wheel always gets the worse of bumps, pot holes, and flats.
- when changing gear it'll affect the torque / speed
- too much weight on the rear = more chances of flat problems, and going up hill the center of gravity will be shifted 90% to the rear wheel.

When i bike up hill i sit take my time, using the shifting gears wisely, i don't stand up on the pedals and hammer it up.

The ekit i have in mind is the BionX PL 350

The reason why i want an ebike upgrade, is only to get some assist on the steep hills, my normal cruise speed on flats is 35 km/h without a sweat, i can keep up with cars and go at 50~60 km/h but then i sweat like as if i came out of a shower with clothes on :lol:

it really sucks to have such a nice ride, and then feel like a snail when going up a hill with cars passing you left and right.

at 35+ km/h cars drivers usually don't mind and just follow behind you, since average rush hour traffic are way slower than that LOL :roflmao2: biking is so much faster at rush hour.

So, my goal is to be able to keep my phase without losing momentum when going up a steep hill, and without sweating like a pig.

Basically i'm just trying to optimize the weight to power distribution ratio, and find out what is most effective setup. :)

- Rear wheel install = power to push forward, will be affected by gear change
- Front wheel install = power to pull forward, gears remains unchanged

.....- might not pull as well, since the weight is mostly on the rear, so it might be losing power to torque.


Rear (and front) hub motors are unaffected by changing the bicycle gears. "Bottom bracket motors" like Cyclone are the only ones that get better torque or speed depending on what gear you choose. The amount of torque and power are not affected by whether it's a front or rear wheel motor.

Most of the time it won't matter whether you use front wheel drive or rear wheel drive, but...

If you want the bike to have relatively even weight distribution (which gives better handling) you want to avoid batteries and motor on the back (or batteries and motor on the front).

Traction will be better with a rear motor, but it'll only matter in really extreme offroad type riding or on snow/ice.

sounds good, yeah i do quite a bit of offroad riding, mainly in grass area, rocks, sands, etc.
and i'm planning to keep riding on winter.

that's why i'm concern about having a good grip, and handling, and even weight distribution, etc

sounds good, yeah i do quite a bit of offroad riding, mainly in grass area, rocks, sands, etc.
and i'm planning to keep riding on winter.

that's why i'm concern about having a good grip, and handling, and even weight distribution, etc

I've got a few variations of ebike setups. I've been riding the crystallite front hub for the last month, everyday and it's great, but is heavy. It weighs in at 25lbs for just the motor. If you chose the bionix 350 it'll prolly come in closer to 15lbs is my guess.

I've ordered the cyclone setup and am awaiting anxiously to try it. I did ride an izip bike which has the setup at the back off a sprocket opposite the cassette. That is a good compromise with the motor weighing next to nothing. Except is didn't last long, motor was too small to go the speeds I wanted to.

I find the more I ride that weight either it be batteries like the sla or nickcad or the front hub is a big factor in how the bike handles and how well it takes the bumps and potholes. If you can afford it, lithium is the best way for light batteries and it will save wear and tear on the bike and give you a more responsive bike if you need to make a quick lane change et... the more weight, the less agility= danger.

Ultimately, low weight and good power can help a rider stay ahead of the traffic which means a safer ride overall. Staying ahead or being capable of following the traffic is much more comfortable and safer because you're not being passed constantly with the chance of a drive making a mistake and you winding up in intensive care. A car bumping you means little to the car but can have disastrous consequences for you the biker.

btw, if you want to offroad, the hubs won't have the power/torque you need and the weight will make it a dog to handle. For that type of riding, you definitely will need lithium strapped low near the backwheel or the bikes mid triangle and a back motor off the left sprocket like this bike- http://evdeals.com/ElectricBikes.htm#NEW%202008%20Rayos%20Electric%20Bike%20(formerly%20Electrec) click the rayos and you'll get the idea. Those motors weigh very little and won't affect the ride much, or this setup from cyclone-

http://evdeals.com/ElectricBikes.htm#NEW%202008%20Rayos%20Electric%20Bike%20(formerly%20Electrec) and scroll down and you'll see the way they work.

Good luck

:)

I have the PL350 and chose to mount it on the rear. This allows access to assist mode which detects and boosts your own pedalling efforts by an adjustable amount. This will allow you to sail up hills in top gear. A front mounting will not be able to use that feature and the throttle will be the only means of control.

A front mounting will not be able to use that feature and the throttle will be the only means of control.

Yes, i was aware of that.

and yes, i was planning to use the BionX more as like a power boost only for when i need it, more than the continuous assist.

However, you did bring out a good point, about going up hills at top gear. :thumb:

sounds like i'll be better off at having it on the rear, than in the front.

I'll just have to play around with the weight distribution, probably have the battery in front, and everything else on the rear or center of the bike.