Help - Problems today with my Synergie - don't know where to start!

[LesleyA]

My love affair with my bargain Synergie which I bought last month for £100 ended today ... OK lets say its temporarily suspended ... hopefully Perhaps someone can make a few suggestions what to look for please?

Been out for about 3 long rides lately, using a mix of pedal only, pedal assist and twist throttle and its seemed fine. This is my first venture into electric bikes, and it did seem a little noisy, but assumed that was just the way it is.

Today, start off OK, but soon bike seemed heavier than normal in pedal only. Just thought I was getting lazy, having the power option at my finger tips, so tending to resort to pedal assist just because I could. After a stready uphill climb, I was convinced bike was not performing normally. Got off and tried to push it, and back wheel is very tight - will hardly spin manually. Also, even when coasting or pedalling with no power, sounds like the motor is running. We turned back from our ride, and pedalling got even more difficult - like I was actually fighting against the motor or turning it myself when pedalling. When I put pedal assist on or used the throttle, bike pulled as normal, although seemed perhaps more noisy. Battery life also seemed to drop quicker, although possibly because I was relying on it more, as pedalling was such hard work. The motor hub also seemed hot to touch after use, but as I haven't checked that before, I wasn't sure if it was normal.

So knowledgable pedelec peeps - where do I start? Is rear brake possibly siezed on? Its a hub type, cable seems to be moving OK on the outside - I thought of tapping the casing lightly to see if something frees up? Or could it be bearings in the hub? Are these serviceable? As I said, the motor is cutting in and pulling well, so I don't think that is at fault.

Any advice gratefully received. Very disappointed at having to cut our trip short, but hoping there is life in the old bike yet ... the 2 wheeled one that is, not me

 

[NRG]

If it runs normally, wheel in the air, on throttle then I suspect the freewheel inside the motor may have got stuck. Not sure how you could free it without taking it apart. You could try and 'shock' it by bouncing the back wheel up and down aggressively...or maybe remove the wheel and hit it with a soft faced mallet.

 

[LesleyA]

Since my earlier post, we've offloaded the bike from the van, and found its working normally now. No more drag on the back wheel and it runs freely when spun by hand. Not long before I noticed the problem today, we'd done a short downhill section, and I'd been braking pretty hard, so maybe brakes are binding and need adjustment, but not sure how to do it. As the hub was hot, wondering if now its cooled down the brakes have freed themselves.

 

[NRG]

Disc Brake? Then yes could be binding...

 

[flecc]

I think this may still be the motor freewheel as NRG originally suggested. Around two years ago a couple of members with Synergies remarked on how the motor drag suddenly increased at about 25 mph downhill, preventing it going any faster, no matter how steep the downhill. At the time we concluded that it was probably an idiosyncrasy of that motor's freewheel.

Your mention of this clearing just after going downhill makes it possible that the freewheel was jogged back into releasing at the point where the binding sometimes happens.

 

[Deleted member 4366]

I would say almost certainly you brakes were binding - maybe because a cable end jumped out of its home after the cable jammed a bit. The motor would make more noise because it's working harder, and for the same reason it would get hot.

If it does it again, feel each brake disk as soon as you stop and see if one is warm/hot, then you know what to fix.

 

[mike killay]

Be careful, disc brakes can get very hot!

 

[jackhandy]

As I read the original post, Lesley mentioned it's a drum brake, or have I misconstrued?

 

[NRG]

Seems to be a rim brake according to the Alien website...easy enough to check and adjust it it is rubbing.

 

[Deleted member 4366]

Sorry, just read it again, but the same applies - just feel the drum to see if it's hot.

 

[LesleyA]

Thanks all for reply and advice!

As I read the original post, Lesley mentioned it's a drum brake, or have I misconstrued?

Yes it is a drum brake, sometimes seen it referred to as a servo brake too. Its one like this:

Steel 95mm bicycle Servo brake - Product Picture From Wuxing Bicycle Co., Ltd.

The lever and cable are moving freely but I guess that doesn't mean its releasing fully inside, or maybe needs adjustment. The bike had been standing for months when I bought it, and everything was very dry. I've oiled up the mechs and cables, but wonder if something inside the brake hub needs servicing too. I assume the pads/shoes inside will need replacing at some point, but having searched online, cannot find any info on how to maintain these.



flecc, re the freewheel suggestion, it was after a downhill section that I first noticed the "drag" and then went on an steady climb and could hardly pedal at all without motor assist! The drag continued for the rest of the ride. Would this still suggest freewheel, or should we now lean towards the brake being at fault, as it was after I'd used them pretty hard that the problem first appeared.

 

[Deleted member 4366]

When the free-wheel jams, you can hardly feel it when riding. The main giveaway is that you can hear it. It's a bit more noticeable on a 20" wheeled bike.

 

[flecc]

That makes it sound like the brake Lesley. On one type of these there is a self wrapping steel band around a steel drum on the hub. When the brake is applied, the steel band is pulled onto the drum and it tends to self-wrap and tighten with the wheel rotation, hence it being called a servo brake, i.e. self acting once applied.

The other type looking like this is the one made well known by Shimano, the roller brake. On this a set of rollers riding on ramps force three steel brake shoes out into a surrounding drum where they grip but have a lesser degree of servo action.

If this happens again, just stop, wheel the bike backwards a little and either type should release.

Both types can be lubricated and the roller type depends on lubrication. The green patch may be a cover for the lubrication point. If it is, it's more likely to be the roller type. Only the right type of very high temperature grease should be used and a small tubes of this can be obtained through cycle dealers. Here's the Shimano part numbers, the smaller size is all you'd need:

Roller brake grease

10 gms Y-041 40020

100 gms Y-041 20400