[Kathy M]

Got to thinking, reading "Lipstick on a Pig" posts... it was mentioned that the rake of the forks and the bars made it hard to do low-speed maneuvers. So for the last couple weeks, I've been working on taking low-speed maneuvers to the Nth... can't say I've had much problem with the stock forks and stock bars, although I could see some benefits to making the mods that he made... But all this did bring up a question, which I'm darned curious about.

I understand the gyro effect, it's actually really cool. But... I've come to notice on my bike that if I do a whole bunch of swerve-type maneuvers, left and right down the road (at speeds ranging from 60 to 5), the bike wants to keep acting like that even when going straight. Kind of like that Harley Wobble that videos were posted about awhile back. But the tires are good, the rear shocks are new, the forks were rebuilt this summer... What is causing this wobble effect? It continues until I come to a complete stop. There were actually a couple times I felt insecure on the bike, which is a true rarity.

Any thoughts? Perhaps some physics involved that I don't know about, or a problem I haven't thought of? Thanks!!

 

[Lakota]

Guessing, Kathy, but in the absense of proof to the contrary I wonder if this isn't a true case of "it's not the bike, it's the rider."
Muscle memory and the inner ear. You become so accustomed to the movement of the bike that it feels weird when it stops.
Like I said, just a guess.
I don't think that there is any law of physics that dictates a wobble to the bike.
Your body, however, expects to continue doing what it's been doing. . . ?
-john

 

[1rusty1]

Hi Kathy. I can't say I've noticed that sensation on my bike but since we have the same model/year, you’re more than welcome to take my bike for a ride to compare. Let me know..

 

[Inferno]

Bent rim?
Loose gooseneck?
Misaligned wheels?
Air pressure incorrect?
Bad wheel bearing(s)?

I would jack the bike up and spin the wheels. You might just find your problem the easy way.

 

[Old Dad]

Worn steering stem bearings,,seems like I've heard that if worn out they will cause this effect.

 

[simpleman77]

Kathy, I've done alot of experimenting in this arena as well, and at all speeds too. I truly can say that I've not experienced any lasting effects of a maneuver once I'm through it. Lakota might be on to something.

 

[FastXR]

Worn steering stem bearings,,seems like I've heard that if worn out they will cause this effect.

I would second this. My guess is the bearings get flat spots in them and when riding un uneven pavenment the bearing flatspots are fighting the tendany of the bike to wander causing a wobble effect. I experience this with my 83 as well and last time I had it jacked up I did notice a very slight notchiness to the steering head bearings. My bike will get new head bearings over the winter.

 

[bullzeyet]

I'd re-torque the steering stem nut to stock torque setting and follow the procedure of putting bike on center stand. Many owners do NOT and think the steering nut is torqued properly...it's NOT!

Re-check fork tube pinch bolt tightness and triple tree bolt torque.

Re-check axle bolt torque or re-do the axle bolt install if tubes were removed. You sure everything is aligned correctly (spacers, speedo thingy, etc,).

IS the tires (front to back) "tracking" straight???? If you can wet the tires front/back then roll it across a dry garage floor surface...you'll see IF the tires are tracking straight. IF NOT...you may have to adjust the swingarm (left/right) OR check that the rear wheel is properly installed and all spacers/pinch bolts/axle bolts tighten in proper order as per owners manual.

Low tire pressure's also contribute to bad handling at low-speeds.

Also agree with "Fast" .

Tire tread wear is also a BIG factor if you've been riding straight line roads and then start doing low-speed manuvers. The slight flat-spot area on the tire surface will give many bad "feelings" to the bike IF your not aware.

Just a few items that I would check and some of the other stuff...I've learned over the years and hundreds of thousands of miles ridden.

Bullzeyet

 

[93gc40]

The 80's VF magnas ans sabers wear prone to a deceleration head shake and wobble. Not heard of it much in the shadows. The only solution I found was proper torques on the stem bolts, and good bearings. All motocycles wear a groves in the neck bearings over time this can also contribute to wobbles.

 

[MikeB]

Lots of bikes have that "headshake" or wobble at certain low speeds. It seems highly unlikely that it's the effect of previous maneuvers, however, since there is really no way those forces can be preserved in the bike's geometry (assuming your forks and shocks are not so worn out that they are "pogoing," which doesn't seem to be the case).

On bikes from a previous Goldwing to my current V-Strom I have found that correctly torquing the steering head bearings has some benefit in this regard, but as others have said tire wear patterns, road surface and a host of other things can be factors.

60mph is pretty fast to encounter this problem. Are you sure it doesn't set in until you begin to decelerate from that speed? Most people find it starts around 40mph while decelerating, and only then with hands off the bars or held very loosely. If you get it at 60 with both hands on the bars that ain't good.

And finally, in addition to the possible causes mentioned you may want to look at your swingarm bearings. Or for cracks in frame welds which would allow some flexing. All these things are fixable.

 

[bedhead]

Guessing, Kathy, but in the absense of proof to the contrary I wonder if this isn't a true case of "it's not the bike, it's the rider."
Muscle memory and the inner ear. You become so accustomed to the movement of the bike that it feels weird when it stops.
Like I said, just a guess.
I don't think that there is any law of physics that dictates a wobble to the bike.
Your body, however, expects to continue doing what it's been doing. . . ?
-john

...THIS.../\...everything else is just speculation

...ever been on a boat and then back on land and you still feel you are on the boat..swaying back and forth?...

 

[Susan07]

:shock: I'd go ahead and check everything out considering it's all fairly simple things. Eliminate the mechanical then...check your own self. Though I can't imagine you would be doing maneuvers for such a distance and time that you would get the "just took my roller skates off" effect.
One should "check" bolt torque on a bike on a regular schedule anyway. Since I ride so much gravel/minimum maintenance roads I check everything on a regular basis due to the vibration.
You might have someone else ride it and see if they are getting the same feeling. :-D

 

[Nehalem Dave]

Kathy, before tearing things apart, it might be your tires. (a) all tires wear a little unevenly and (b) if you have run the bike any distance with an under inflated front tire it will develop scallops. We have noted that new 880s track with no wobble. After about 1/2 tire life, they all wobble hands-off at about 35-40 mph with the severity varying widely from barely noticeable to bothersome. 'Head Flop' varies by bike model/rake and more floppiness accentuates tire wobble. PS: pavement is not perfectly even either.

Jez my $0.02

 

[simpleman77]

...ever been on a boat and then back on land and you still feel you are on the boat..swaying back and forth?...

Yeah, but that's from the rum. :shock:

 

[markspike]

Kathy....smokin' that wacky-tabaccy again?:shock:

:lol::lol::lol:

 

[Susan07]

Kathy....smokin' that wacky-tabaccy again?:shock:

:lol::lol::lol:

:shock: Again? Didn't know she quit! :lol:

 

[simpleman77]

Kathy....smokin' that wacky-tabaccy again?:shock:

:lol::lol::lol:

Yeah, but that's from the rum. :shock:

 

[simpleman77]

:shock: Again? Didn't know she quit! :lol:

Yeah, but that's from the rum. :shock:

 

[bedhead]

Yeah, but that's from the rum. :shock:

...and you have had too much sir!...

 

[Doc Moore]

I understand the gyro effect, it's actually really cool. ..
Any thoughts? Perhaps some physics involved that I don't know about, or a problem I haven't thought of? Thanks!!

So I hate to break this to everyone, but the gyro effect is not what keeps a bike upright. In fact, science cannot explain it at all...

Revisiting bicycle physics Cyclelicious

No idea on the wobble!

Doc