Very bad head shake or shimmy

[ex10psi]

I am getting a very bad shake and shimmy when i take my hands off the handlebars for just a brief moment (like adjusting my gloves, etc...). It hits hard when i hit 15mph and higher. It wasnt an issue when i first got the bike and have since put about 500 miles on it when that shimmy started happening.

has anyone else experienced this? i had a bike shop tighten the headset top bolt and everything in that general area and the shake is still there.

thanks for any help.

 

[britannic]

I had something similar from new; setting the headset with just the right amount of preload fixed it and also got rid of the front brake judder at the same time.

 

[britannic]

Did they check the bearings? Is there any noticeable play in the head end?

 

[ex10psi]

Is there some special procedure to get the right amount of preload? The shop tightened it but didn't look like anything special.

They didn't check any bearings. There's no play in the head end. The shimmy is bad. Appreciate you chiming in.

 

[Neil]

I have the same thing on my ST2, I was surprised the first time it happened. It really is only noticeable at higher speeds. Also .worse when I have a pannier on the back.

 

[britannic]

I recommend eliminating the headset adjustment as a cause first, by confirming it is adjusted the way you want. Note, adjustment is more about feel than being able to use a series of torque settings etc. It's not difficult to do yourself and the late Sheldon Brown has some good info on how here.

Once that is confirmed, you'll want to check the tires/wheels for any obvious distortion and that they're both in line with each other and the frame etc. The bike shop should be able to diagnose the issue, but my experience was that my bike shop caused the problems by not setting my steed up properly. I ended up fixing it all myself and it rides perfectly now (41mph down a hill recently and no issues). I do have a rack and rack bag as well.

Some more info on possible causes can be found here and here.

Also make sure that both axles are torqued correctly. When is all is said and done, you may still have the issue, since the rider can be part of the equation as noted in the links I researched.

 

[HaveBlue]

I am getting a very bad shake and shimmy when i take my hands off the handlebars for just a brief moment (like adjusting my gloves, etc...). It hits hard when i hit 15mph and higher. It wasnt an issue when i first got the bike and have since put about 500 miles on it when that shimmy started happening.

has anyone else experienced this? i had a bike shop tighten the headset top bolt and everything in that general area and the shake is still there.

thanks for any help.

One of my criteria for buying a new bike was, no shimmy with my hands off.
My Neo-Carbon had very bad shimmy with hands off. I tried putting on a carbon fork from my Neo-Race (solid bike btw), still shimmied. Tightening the headset, removing weight from the rack, nothing solved the shimmy except Craigslist. I test rode an ST-1, Shimmy. I ended up with a Nitro-Cross from Crazy Lenny's. Solid bike, small battery.
Hope your problem gets solved. If it does, let us know how you solved it.

 

[ex10psi]

I recommend eliminating the headset adjustment as a cause first, by confirming it is adjusted the way you want. Note, adjustment is more about feel than being able to use a series of torque settings etc. It's not difficult to do yourself and the late Sheldon Brown has some good info on how here.

Once that is confirmed, you'll want to check the tires/wheels for any obvious distortion and that they're both in line with each other and the frame etc. The bike shop should be able to diagnose the issue, but my experience was that my bike shop caused the problems by not setting my steed up properly. I ended up fixing it all myself and it rides perfectly now (41mph down a hill recently and no issues). I do have a rack and rack bag as well.

Some more info on possible causes can be found here and here.

Also make sure that both axles are torqued correctly. When is all is said and done, you may still have the issue, since the rider can be part of the equation as noted in the links I researched.

really do appreciate your input and help here. you have proven to be more helpful than the local stromer dealers near me who sadly are not much help. however, the stromer support manager here in the US has been super helpful and good to work with. i am waiting for his response on this.

also, i've taken the bike apart and checked the wheel bearings, checked the head tube again but i dont know much about it so all i can say is it feels nice and tight and not too tight, per those links you sent me. so i am thinking its good there but i'm not too sure. ive got the bike apart (wheels off) so i'm going to just bring the whole thing to a 3rd stromer dealer that i've not visited yet. i'll take it there tomorrow and just drop it off in pieces and have them review it over.

i'll keep you guys in the loop. i really dont have a lot of patience and time to deal with this and like another poster mentioned here... if this doesnt get resolved by one of these clueless dealers, i'm going to return the bike or sell it.

 

[ex10psi]

i just got a call from the bike shop and they said they couldnt repro the problem, but admitted that since it's not their bike they didnt try to take their hands off too long. i'm going to ride one of their demo ST2's to see if that one wobbles too. he said that nothing was wrong with the headset. he did say the tire did have a bit of a wobble to it when riding and looking down at it. i am thinking about possibly replacing the tires with those marathons and something of lower profile and thinner, less knobby, for more speed. maybe that'll solve my wobble issues? how likely could it be the tire? the shop said the wheel looked just fine.

the hubs look fine too, forks as well. he also mentioned the motor being in the back doesnt help with weight distribution, just more weight back there causing the front end to be lighter relative to the rear.

i will try the other ST2 and see if it does wobble... and/or replace the tire and will post back. any further ideas greatly appreciated!

 

[Berry78]

They dont wanna take their hands off? Strange.. I was taking my hands off my handlebars when I was 8...

 

[Robie]

Ex 10 psi
Cane Creek has a product that might help. It is a shim ( like a thin washer) that goes between all those parts you took apart on the headstock. When the bike starts wobbling the friction on the washer makes it swell which is supposed to solve head shake. Carrying extra weight in my rear panniers pretty much solved my head shake on my St2 . Good luck with yours

 

[bikerjohn]

My EG Zurich suffers from the same issue. keeping one finger on the handlebar eliminates the wobble, so I've lived with the characteristic for the past 5,000 miles. Recently, I put the bike on a stand and while operating the motor on the stand I noted the wobble under no-load. It seems as if the geared hub motor creates the condition.

 

[ex10psi]

@Robie and @bikerjohn - thank you for chiming in your experiences and suggestions, thats helpful and interesting especially the wobble on a bike stand while operating the motor! wow.... so i test rode another ST2 that they had on the showroom floor yesterday at the bike shop when i went to pick up my bike.... and yes, that other bike also exhibited the same wobble! my bike will wobble even more when i have weight in the back in the panniers so opposite of what you are noticing robie.

i like the idea of the cane creek product, i need to look that up and possibly give it a go, thank you for the suggestion!

so at the end of the day, nothing got resolved on my bike. it was taken apart, looked at, test rode, and the wobble is just there. maybe i need to accept the fact that its all part of having a rear hub motor. i will try looking at some other products like that cane creek shim thing to see if that helps. i was also going to replace the stock tires with a set of marathons, thinner, to see if that helps too. the shop ordered a pair of tires for me so i should be getting those put on later this week.

 

[britannic]

@Robie and @bikerjohn - thank you for chiming in your experiences and suggestions, thats helpful and interesting especially the wobble on a bike stand while operating the motor! wow.... so i test rode another ST2 that they had on the showroom floor yesterday at the bike shop when i went to pick up my bike.... and yes, that other bike also exhibited the same wobble! my bike will wobble even more when i have weight in the back in the panniers so opposite of what you are noticing robie.

i like the idea of the cane creek product, i need to look that up and possibly give it a go, thank you for the suggestion!

so at the end of the day, nothing got resolved on my bike. it was taken apart, looked at, test rode, and the wobble is just there. maybe i need to accept the fact that its all part of having a rear hub motor. i will try looking at some other products like that cane creek shim thing to see if that helps. i was also going to replace the stock tires with a set of marathons, thinner, to see if that helps too. the shop ordered a pair of tires for me so i should be getting those put on later this week.

If it wobbles on the stand, then the issue is definitely imbalance in the wheel and/or its components, since it eliminates all of the other factors. I'm wondering it there is a way to add compensating controls to the wheel in the same way a car wheel is balanced after new tires are fitted.

 

[opimax]

If my st1 or 2 did this i would not have bought them! when I first had my new Stromer shock fork on the st2 installed it was a little more difficult but after a while i am more used to it , not as easy certainly doable for extended distances. My wife's st1 step through can have some issues if the rear is not balanced, it too does not have the solid fork either

 

[bikerjohn]

I figure the wobble is caused mainly by the hub motor planetary gearing or perhaps from magnetic pulsation as the hub rotates with or without electrical input from the battery. If there was a practical way to compensate the imbalance then maybe the condition could be alleviated. Still, the wobble is unnoticeable as long as you maintain contact with the handlebar.

 

[smitty]

I figure the wobble is caused mainly by the hub motor planetary gearing or perhaps from magnetic pulsation as the hub rotates with or without electrical input from the battery. If there was a practical way to compensate the imbalance then maybe the condition could be alleviated. Still, the wobble is unnoticeable as long as you maintain contact with the handlebar.

curious bikerjohn...my understanding of the ST-1 or ST-2 is that the hub motor is "direct drive" which I understood to be absent the planetary gears in a "geared" motor? It would also seem that wobble up front might be more likely to be caused by a hub motor located on the front wheel as opposed to the rear hub motors located on all Stromer's? Just some thoughts out of curiosity and perhaps some ignorance on my part.

 

[bikerjohn]

curious bikerjohn...my understanding of the ST-1 or ST-2 is that the hub motor is "direct drive" which I understood to be absent the planetary gears in a "geared" motor? It would also seem that wobble up front might be more likely to be caused by a hub motor located on the front wheel as opposed to the rear hub motors located on all Stromer's? Just some thoughts out of curiosity and perhaps some ignorance on my part.

I'm guessing that a front hub motor may cause a more pronounced wobble than a rear hub. Whether front or rear drive, I would guess too, magnets in direct drive hubs may also be contributory factors for wobble on bikes with that type of motor. I would guess further, a typical crank drive set-up does not suffer a wobble condition. So my thought is that shimmy/wobble is inherent in a hub motor design