Instability at high speed...

[VictoryHammer2006]

So I went for a longer ride today, on the back roads I noticed the suspension seemed harsh on the cracked roads around here......when I got to my half way point for lunch I checked the tire pressure. Both on the TPMS and a handheld gauge. Both tires were about 4-5 PSI over what they were when I started. Obviously this was caused by the tires warming up, I never thought it would add that much. Starting pressure was, 32 front 40 rear. When I checked it the front was 36 and rear was 45. While they were still warm I dropped the front back down to 32 and the rear t0 38. As expected this mad a big difference in handling and ride. I ended up on the interstate and figured I'd see if the pressure changed changed anything......it did! The shudder didn't start until 92 actual speed 99 indicated. On top of that it wasn't nearly as noticeable. In fact it could have been wind buffeting causing what I was feeling.

Next step is to reset the suspension to where it was and keep an eye on the pressure to see if it comes back.

All that said I still think it will be a good idea to balance the wheels.


Eric you are 100% correct, I have bad habit of making multiple changes and I know its a bad practice....

Offcamber, please post the solution when you figure it out. I'm having the same problem and losing sleep over it. I'm about to go buy a stock metz front to see if the problem goes away.

 

[offcamber]

Let me be clear on one point its NOT a wobble, I should not have used that term. The handle bars do not move left to right....its a vibration or shutter. The bike doesn't feel like its going veer off or lose control. Its vibrating enough at near 90mph that the windshield and mirrors start to bounce.

As said for me tire pressure helped some. Most local folks I talk to say its most likely tire balance. I haven't had time to pull the wheels yet and check.

Its not a major issue right now since I don't generally ride at 90 mph.

 

[EricV]

Re: Vibration at high speed...

Let me be clear on one point its NOT a wobble, I should not have used that term. The handle bars do not move left to right....its a vibration or shutter. The bike doesn't feel like its going veer off or lose control. Its vibrating enough at near 90mph that the windshield and mirrors start to bounce.

It would have been helpful if you had not labeled the thread "instability", as that is not what you're describing, just some vibration. The Anakee 3s I mounted recently do the same thing over 75, and while they got a little better after ~2k miles, they still vibrate the mirrors at 80, (legal I-15 speeds here), enough to not provide a clear rearward view.

 

[shrekonwheels]

Mine started doing that at 80 as well, I changed the final drive fluid and it seems fine now.

 

[offcamber]

Re: Vibration at high speed...

It would have been helpful if you had not labeled the thread "instability", as that is not what you're describing, just some vibration. The Anakee 3s I mounted recently do the same thing over 75, and while they got a little better after ~2k miles, they still vibrate the mirrors at 80, (legal I-15 speeds here), enough to not provide a clear rearward view.

Its more than just vibrations....I used to get that on my Versys, that was engine vib....

Its not violaent by any means but its also not as it should be because when I first got the bike 2 years ago it was solid as a rock.

I just did a final drive oil change this past winter....I have maybe 500 miles on the fresh oil.

 

[shrekonwheels]

Change the tires, they can be defective or whatever, I will not mess around with tires, they are your only contact point to the ground.

 

[tomatocity]

I had a rear Heidenau K60 separate and they replaced it immediately, no questions asked. So they know of this occasional problem.

 

[estrasil]

I wish this thread had continued to a proper conclusion.

I have a 2013 Tenere. I bought it at 10k miles, and until 23k miles it ran smooth at any speed. Super fun. But now on my commute to work, where I regularly hit 90+ per speedometer, it has an oscillating shudder (by oscillating I mean it shudders, stays stable about a second, shudders again, stays stable about a second, etc.) that shakes the signals and this shudder does not go away as the speed increases. I tried to experiment getting up to 100 and pulling the clutch in to see if it goes away, but the speed drops so quickly back down to below 90 that I have no conclusive evidence of any relation to the drivetrain. I have Heidenau K60's. The front tire was worn to abut 1/16" before the wear bars. I went to the shop and they said I had 30psi in the tire. Filled it to 36psi and took a test drive... no difference in shudder. Bought a new tire and replaced it. No difference in shudder. Turned the rebound damping on the front shock out 1 click at a time for 3 clicks, the went 5 clicks the other direction. No difference.

I am completely perplexed. Bike is super smooth below 90mph. Shudders above 90mph no matter what I do. And it is a new thing. Only other thing I have changed is I did get a new rear tire probably not too long before I noticed the shudder.
I've dropped the bike in super slow mo at a gas station, but it shuddered the same before and after that drop.

 

[Cycledude]

Maybe the problem is caused by the not to long ago new rear tire .

 

[Checkswrecks]

I wish this thread had continued to a proper conclusion.

I have a 2013 Tenere. I bought it at 10k miles, and until 23k miles it ran smooth at any speed. Super fun. But now on my commute to work, where I regularly hit 90+ per speedometer, it has an oscillating shudder (by oscillating I mean it shudders, stays stable about a second, shudders again, stays stable about a second, etc.) that shakes the signals and this shudder does not go away as the speed increases. I tried to experiment getting up to 100 and pulling the clutch in to see if it goes away, but the speed drops so quickly back down to below 90 that I have no conclusive evidence of any relation to the drivetrain. I have Heidenau K60's. The front tire was worn to abut 1/16" before the wear bars. I went to the shop and they said I had 30psi in the tire. Filled it to 36psi and took a test drive... no difference in shudder. Bought a new tire and replaced it. No difference in shudder. Turned the rebound damping on the front shock out 1 click at a time for 3 clicks, the went 5 clicks the other direction. No difference.

I am completely perplexed. Bike is super smooth below 90mph. Shudders above 90mph no matter what I do. And it is a new thing. Only other thing I have changed is I did get a new rear tire probably not too long before I noticed the shudder.
I've dropped the bike in super slow mo at a gas station, but it shuddered the same before and after that drop.

I'd try lubing and re-torquing the steering head.

 

[WJBertrand]

Clutch basket going?


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[Nikolajsen]

9 out of 10 times this is steering head, or tire.

 

[scott123007]

The rear tire is your culprit, but both tires need to be re-checked for balance if you commonly run at high speeds. The reason the shudder is not constant is because of the two different circumference's of the tires.

 

[Checkswrecks]

The rear tire is your culprit, but both tires need to be re-checked for balance if you commonly run at high speeds. The reason the shudder is not constant is because of the two different circumference's of the tires.

I think I'm a bit confused by what Estracil is describing. If it is a handlebar shudder or handling issue, and he already replaced the front tire and has enough pressure in it, then likely the steering head which I mentioned in the previous post.
If the "shudder" means something vertical, like suddenly riding across some really rough surface, then I'd agree with Scott about the rear tire, especially if it is an older K60.

 

[Don in Lodi]

Tire balance on the new tire?

 

[scott123007]

I think I'm a bit confused by what Estracil is describing. If it is a handlebar shudder or handling issue, and he already replaced the front tire and has enough pressure in it, then likely the steering head which I mentioned in the previous post.
If the "shudder" means something vertical, like suddenly riding across some really rough surface, then I'd agree with Scott about the rear tire, especially if it is an older K60.

Bob, the way I'm picturing what he is describing is the "galloping" that almost every dirt bike does when ridden on the street. People think it is the knobbies that cause that, but it's not. It's tires that are WAY out of balance because of the rimlocks. Wrap enough solder around 5 or six spokes on the wheels until they balance out, and presto, the bike rides smooth as silk.

I think his problem is the same. Someone either did not, or did a shitty job of, balancing his rear tire when it was installed. Although some tires don't need much weight, some do, and the faster you go, the more balance becomes an issue.

 

[Nikolajsen]

It does not have to be the balance, that is the problem.
It could very easy be the tire, that isn't in the prober place on the rim. Or the tire tread that simply is bad..

 

[scott123007]

It does not have to be the balance, that is the problem.
It could very easy be the tire, that isn't in the prober place on the rim. Or the tire tread that simply is bad..

Except that in almost every case, out of round and imperfect bead seating issues are most noticeable at lower speeds. Balance problems magnify as speed increases.(He stated the bike rides smooth as silk below 90 mph)

 

[gunner]

What sized windshield is on your bike? Do you have a trunk? If so what size and how weight is in it? Those can contribute to instability at high speeds.

 

[Don in Lodi]

Except that in almost every case, out of round and imperfect bead seating issues are most noticeable at lower speeds. Balance problems magnify as speed increases.(He stated the bike rides smooth as silk below 90 mph)

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