PCeBiker
No-Hands No-Pedaling No-Credentials
- Region
- Canada
Wobbles are easy.
Just put 20-50 pounds on the rear rack, and take it for a spin.
Ride it no-hands, and it will wobble.
New X-Peak
- Thread starter Bo2255
- Start date
Wobbles are easy.
Just put 20-50 pounds on the rear rack, and take it for a spin.
Ride it no-hands, and it will wobble.
Chazmo
fat-tire biker
- Region
- USA
- City
- Central Massachusetts
Do you know why, PC? I’m kind of curious about this phenomenon. Seems to me like it’s something that could be diagnosed. But, I’m talking completely from ignorance.
FYI, I was going to put a spare battery on my rear rack on Fättie, but both spare batteries that I got are non-functional, so it’s a non issue. With the rack unloaded, there’s no wobble at all, but I presume that is the case for you (and others) as well.
I’m just curious about what’s causing the oscillation. Is it a wheel truing issue? Is something not “tight” with the rack mounted to the back of the frame? ??
PCeBiker
No-Hands No-Pedaling No-Credentials
- Region
- Canada
I'm not really sure what exactly causes it but adding weight to the rear, especially with the center of mass high off the ground, and even behind the rear axle, it's probably going to happen.
It's a bit like that one wheel on a grocery cart that always wobbles.
I know that frame flex has a lot to do with it, and step-through frames are generally worse for wobbling.
@Nvreloader had a wobble so bad that he couldn't control it, but that was with a lot of weight on the rack.
Moving the weight forward over the front wheel made a huge difference.
My ebike would only wobble when I let go of the handlebars, and I tried Everything to get it to stop.
I spent months truing and even balancing my wheels (with solder wrapped around the spokes) but the only way to stop the wobble was to mount my second battery on the top tube.
That turned into real challenge, but I managed to make battery brackets out of polymorph plastic and finally got the battery mounted to the top tube where the 15 pound battery was centered better between the wheels, and was now fully suspended by my full suspension frame,..
Just try it and see what happens.
You've got a step over frame, so you'll probably be OK, unless you want to ride no-hands.
My ebike would only wobble when I road no-hands with the second battery on the rear rack, and riding no-hands is what it's all about for me. (I've got over 5000 km on my ebike now, with 4000 km of that with no-hands on the handlebars.)
I also tested a second battery on the rear rack of my first ebike, and the same wobble happened, but only when I rode no-hands.
Putting the battery on the front rack stopped the wobble though.
(I reinstalled the front rack for the road test.)
It is a step through bike but there was no wobble with my hands on the bars, and I could ride no-hands with the battery on the front carrier.
EDIT: I read through the link below, and putting the battery on the front carrier Did Not stop the shimmy.
My front rack is frame mounted though, and if the weight of the battery itself was on the forks, it probably would have stopped the shimmy ??
Last edited:
stompandgo
Well-Known Member
- Region
- USA
PCE's bike has a full suspension frame. I'd look there first. Disconnect the rear shock and check the pivot bushings for play.
PCeBiker
No-Hands No-Pedaling No-Credentials
- Region
- Canada
My e-bike is fine now.
I just had to get the battery mounted to the top tube.
There's no hint of a wobble anymore.
I can ride through 2" deep pot holes with no-hands, and my e-bike just floats right through it.
I'm only allowed to go 20 mph, so I keep things exciting by riding no-hands.
No-hands in 20 mph crosswinds on loose gravel roads is a challenge.
If I screw up, I'm dropping 10-15 feet into a 20 foot deep irrigation/drainage channel,..
The water is disgusting too.
Chazmo
fat-tire biker
- Region
- USA
- City
- Central Massachusetts
That seems most likely.
Chazmo
fat-tire biker
- Region
- USA
- City
- Central Massachusetts
I do believe you, PC, but I’m having trouble imagining what the cause is. It’s gotta’ be something oscillating. Your step-thru fatty seems to have a properly secured rack (and no rear suspension). I think it might just be flex in the frame because of the construction. Why would a hand on the bars make a diff? Forgive me, again, just trying to analyze (armchair)..
PCeBiker
No-Hands No-Pedaling No-Credentials
- Region
- Canada
Check out this thread.
It covers a lot of what we went through to stop the shimmy,..
Thread 'Where is the problem located at?' https://forums.electricbikereview.com/threads/where-is-the-problem-located-at.56068/
It covers a lot of what we went through to stop the shimmy,..
Thread 'Where is the problem located at?' https://forums.electricbikereview.com/threads/where-is-the-problem-located-at.56068/
PCeBiker
No-Hands No-Pedaling No-Credentials
- Region
- Canada
@stompandgo , I don't know what you're riding, but if you've got an e-bike that weighs more than 20 pounds, and it's got a rack on the back, strap a 15 pound battery to it and see what happens.
You may need to ride no-hands to encounter problems, but it's not safe to do that anyway, so I don't recommend it.
stompandgo
Well-Known Member
- Region
- USA
Right now I'm riding a Cannondale Tesoro with a Topeak rack. I've only had about 10 pounds in it, with two large bottles and an Abus lock. No wiggle at all, but I don't ride no hands, and mine is a hardtail.
