Low Speed Front End Oscillation

[OmegaSix]

I've noted that my 03 does the decelerating head shake MORE when I have more weight to the rear - ie bags and Givi topcase attached. Take that stuff OFF and the head shake goes away completely.

OK - now that I said that - an adult weighted passenger also makes it go away...

Some subtle effect of balance at the rear axle?

 

[socalrk]

I hope that the new Avons will cure the front end wobble. I guess some of the bikes have a shake problem but mine became steady after new tires.

 

[JimV]

I'm not sure if this belongs here or not but...

I've noticed that my handlebars oscillate at 40-50 mph but I only notice it if I ride no-handed. The bike only has 5k on it and the tires are new (~1k) Avons.

Its not really a problem per se but I'd like to make it go away. I just got ABM rotors and I think I'll get the wheel rebalanced after replacing the rotors.

I'll try to check the axle and bearings while the front wheel is off as well. I'm also going to have to recheck the forks. I had the bike back to the dealer once because the steering head was loose causing it to "clunk" a bit during braking.

Is there anything else that I should check?

Is this something that a fork brace might help?

Finally, does anyone know what size socket I need to get the steering stem nut off?

Thanks,

Jim

 

[Woodstock]

I think that's the classic sign of steering head nut needing to be re-torqued.

 

[Oldwin1]

OK

I had been away from the board for a while and just checked this post. I have replaced rotor, break pads, torqued the stearing head, replaced the tires. I still have a shudder at low speed breaking and a wobble around 45. The wheel bearings feel fine and are definately not sloppy. I keep hoping someone who has found the cause for this will chime in.

Ron

 

[Bostonfan2]

Same problem here. After last tire change (new avons) the tech re-torqued

the stearing head bearings which somewhat helped, after a few thousand miles

its back and worse than ever. Its strange, over 60mph its solid , the tech tried

everything and finally just said to "always keep your hands on the bars" .....which

is fine...BUT...still shouldnt be happening..

Ray

 

[OrangevaleFJR]

Still no definitive answer on this one. For the first time, two days ago I was coasting at 40-35-30 in 4th gear. Hand off of bars and they started a slight wobble that went away as soon as my hands were on the bars...could not feel the oscillation at all, but it was enough to get them moving about an inch either way of center at the grip ends.

I have Avons with about 3000 miles on them. I noticed a slow turn wobble when I first got them, but never a straight line wobble. I would guess tire wear, or stearing head looseness first.

Anyone figure this one out yet?

 

[weekend rider]

everyone has checked what seem to be the problem. Has any one thought about having their rim checked to see if it is true? Or havng tire checked to see if it is true? or how about re-balsncing the front rim?

 

[Captain Obvious]

I hope that the new Avons will cure the front end wobble.  I guess some of the bikes have a shake problem but mine became steady after new tires.

Hmm.. I thought that the Avons were the cause of the wobble. :eh:

There was some chatter about Avon shod FJ's with the same symptoms on the FJ list a while back too. I know mine wandered like a drunk sailor at slow speeds, but seemed okay at speed, although very sensitive to any bar input.

Any talk on other boards about these symptoms with the Avons?

Edited to say, I answered my own question. I just googled "Avon Tire Wobble" and there is lot's of chatter about the same symptoms on other bikes.

 

[Saddletramp]

Hey CowboyDiesel,

Did you happen to catch my thread two weeks ago when my front Metzler blew a hole in it while I was doing 80MPH! My tire looked good too, although I did have 12,000 miles on it!

If you can see a ridge on the center portion of the tread, thats the steel belts trying to crawl out from the rubber! They will eventually find thier way out!

Replace the tire! :bigeyes:

 

[BBIII]

modified post, I have no opinion.

 

[Bounce]

Well, my problem has now turned into a full blown tire failure.  Doing 70 on the highway last night it suddenly felt like I had a flat tire so I pull onto the shoulder and inspect the tire.  Still full of air but the center of the front tire had a major bubble for quite a ways around the tire. 9500 miles on the tire. I know that's on the high end mileage wise but it still had tread left.  Anybody have any luck with Metzler replacing these?Ordered a set of Avons today.  Looks like I'll be on four wheels for a few days.

YIKES! Another Metz critical failure! I'm not sure I'd want them to replace it unless they let me pick a different brand.

The fix for wobble when riding without hands is to not ride with your hands off the bars. DUH.

If you've checked the balance of the tire, and the trueness of the tire/rim/rotor, then you might service the steering head bearing if you haven't already done so.

 

[rocketdoc]

@CowboyD, the first problem was obviously the tire, probably a belt, but the nature of the Avons with the deeper tire grooves, does have some ossilation slowing down. This goes after the tire has a few hundred km on it, at least mine did. I have noticed as they are getting close to the end, the feeling changes as well even with slight cupping. Are you running 40-42 psi? Try it.

Tire pressure variations do change the feel of the bike incredibly, so much so, I am considering installing a constant tire pressure monitor on my next full set change.

 

[tyronewildman]

Guys, Guys---Get serious. All bikes have a front end wobble. That's how they steer streight or turn. They go left & self correct & go right & self correct and so on. Believe me, if you look at a tech drawing of a M/Cs path of travel you'll see this. Usually this wobble is so slight that it's unnoticeable. The dampening effect of your hands on the bars & the tightness of the steering head bearings usually keep this oscollation down to such a low frequency that it is unnoticed. Anything that puts more weight on the front tire makes it harder to self correct and finally when it does self correct it swings to the other side futhur than normally & that's when you feel it. Taking your hands off the bars, or loose steering head bearings, takes away the dampening & slowing down puts more weight on the front tire. Now putting more weight on the back tire (passenger) makes it easier for the unloaded front tire to self correct & less noticeable wobble. Higher speeds makes it easier for the tire to self correct. Ever notice when a grocery cart has a front wheel wobble---they work the same way---when they are right you just can't see the wobble cause it is very slight. Tires cup & some more than others & this also effects the amount of wobble. Hitting a object on the side of the front tire while at low speeds with your hands off is inviteing a bad wobble. Keep thase hands on the bars... Later,,, De