Is it just me? Probably.
 

I have a Bionx PL350 on my old DiamondBack Approach Hybrid. It works pretty well, although it has cut off unexpectedly twice and a restart fixed it.

However, sometimes it doesn't offer the amount of assist I expect and was wondering why. Sometimes the assist bars on the controller display show more assist than at other times under the same load.

The last hill by my house, on the way home, is very steep and there appears to be no amount of assist that can help me up the hill.

I'm 5'10" and 220 lbs, but I don't look that heavy, even with a bit of a belly.

Anybody know why the assist seems inconsistent? My guess is that, on the very steep section, the overall weight of the bike and me vs. gravity is overpowering the motor's ability to assist.

Anyway to overcome this?

Just hoping someone has some ideas.

I read something a while back about the motors cutting off and on if not installed properly. There are some things that have to be set right on the wheel. The direction that your wheel is removed from determines the angle at which one of the crucial pieces should be installed. (Sorry about that vague description. I'm not mechanically inclined, so I had the guys at the LBS install mine.)

You can contact the Bionx dealer and/or look up the installation videos for Bionx. (I found some on YouTube by searching for Bionx installation.)

It is possible that a loose wire somewhere would create the problem you describe.

Hmmm. I did have to disconnect them to fix a flat, about a week after having the kit installed. Maybe, I'll check the connections again, couldn't hurt.

Happens on the same hill all the time, so I'm guessing it's me, but no one else experiences it at the same spot.

I wonder if my weight is just overloading the motor?

On a really steep and incredibly short incline (75 degrees for less than 10 feet), my Bionx couldn't do the trick, even with me pedaling. Also, I started the climb from a dead stop, and it was in wet grass. I weigh around 165 lbs. and I ride a bent (I'm guessing 30 lbs. with bike and motor) while hauling 5-10 lbs of stuff. The motor didn't cut out, either. It just didn't have enough power to pull me all the way up without tipping over.

Other than that one episode, I've not had a problem with inclines.

...I'm thinking that it's something electrical/ mechanical and not your weight.

"On a really steep and incredibly short incline (75 degrees for less than 10 feet), my Bionx couldn't do the trick, even with me pedaling. Also, I started the climb from a dead stop, and it was in wet grass. "

I'd like to see that incline, do you have any idea what a 75 degree incline is? You would not get traction to start at all let alone pedal up it :)
This is only around 38 degree.
http://web.presby.edu/~jtbell/transi...n/FullView.jpg

This is incredibly steep, and is in the middle of a longer gradual hill. The steep section is about about 50 yards, then goes back to the gradual slope. When i hit that section the motor assist "grinds" to halt, as far as boost is concerned. After the steep part, the motor comes back in fine.

Even though the gears don't affect the operation of the motor, I find that a mid range gear works best in this situation and I just stand up and pedal through it. I don't have enough space to go all the way down to a granny gear.

I shut the motor off once coming up to the entire hill and actually did put it in first gear and got up it OK, but boy, is that a lot of work and slow when you're used to the speed of the boost.

Hundreds and hundreds of cyclists go by our house everyday, most on road bikes and in the summer, when the windows are open, first you hear the panting and then the metallic clicking and clanking of derailleurs and slowly they reach the top and go past our house.

So, I don't know the % or degree of the really steep section, but it's like hitting a wall. Maybe the motor and controller can't work that suddenly?

I sometimes feather my brakes while trying to accelerate ( I know its silly) and that gives me the symptoms of a motor thats cutting in and out.

I'm assuming that 90 degrees would be straight up, at a right angle from the ground. (Something I have not ever seen and don't believe actually exists.) Thus, 45 degrees would be half way between straight up and flat surface. ...I'm actually sitting here with a calculator and my arm as a guage, so the angle may have been more like 60-70 degrees? I started at the bottom, with my front wheel touching the beginning of the incline.

...And as I readily admit, I did not pedal up it. I had to get off and walk.

BTW, I've also tipped over on a 125 Suzuki dirtbike under similar conditions. Ended up having to walk it up. So back to my original point, which is that the Bionx shouldn't be cutting out on most hills.

What does it mean to "feather your brakes" ?

People often greatly overestimate slop angles. Your slope, was certainly less than half the angle you suppose.

Consider that few expert ski slopes (at resorts) exceed 45 degrees. Trust me, you don't ride up these. 50 degrees has the appearance of a freakin' wall. More quantitatively, a bicycle tire has a coefficient of friction between 0.5 and 0.8, meaning it will slide off slopes above a critical angle somewhere between 27 and 39 degrees. That's on dry asphalt. On wet grass, it won't even be close.

My protractor happens to be on my desk, so I used it to find a good example of steepness for you. Find a picture of the Eiffel Tower (looking at one of its sides) - the bottom and middle sections are about 60 and 70 degrees, respectively.

Its a phrase that I've used to describe lightly pulling my brake lever. Its generally just a finger tip thing for me, I don't actually try to squeeze my hand shut.

I guess the 'feather' part of it is a reference to how much weight or force is being used on your brakes.

i've used this expression for 20 years, do you use a different expression to describe the same thing?

For the first time, today, the motor seemed to work fine on the steep section. Of course, it's extra hard, but the motor seemed to be finally contributing to my effort.

I went down a gear on the front sprocket and on #4 sprocket on the rear. I've tried that combination before, but it has never worked as well as today.

My neighbor says I'm just getting fitter and more able to climb the hill. Since the motor adds assist in proportion to what I'm able to provide and being fitter I'm adding more of my own effort. That's why it was easier today.

Hmmm. Could be.

I might say "lightly braking." I had just never heard the feather expression.

This use of "feather" probably comes from this meaning: to turn the blade of an oar so it cuts through the air with little resistance. Feathered brakes offer little resistance. Q.E.D.

you guys are just screwing with me, right?

If you google the expression, I'm certainly not the only person using it:

http://www.google.ca/search?q=feathe...ient=firefox-a

Last couple of days the motor has actually worked pretty well going up that hill. Only thing I did different was disconnect the right hand brake connector for the regen. That's always been a little screwy.

I've heard of the term feathering to mean doing an action lightly and repetitively. Usually, feathering the gas pedal on a car that has a vacuum leak or something like that, to keep it running.

I suspect they really never heard of the expression.

I have, but I'm not surprised that there are people who never heard of "feathering" brakes.