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Death wobble?

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Old 05-16-2011, 01:44 PM
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Default Death wobble?

iT's on the news tonight.
What is this hd "death wobble?
 
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Old 05-16-2011, 01:58 PM
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The physics of a wobble are hard to explain (and after reading up on it several times now, I still am not confident I fully understand it.) It is influenced by the gyroscopic forces of your rotating wheels and to some extent by the rotation of the motor/transmission. Bottom line is... your bike can develop an oscillation in the front tire that results in the wheel wobbling very rapidly back and forth; also known as "tank slap". If it happens at high speeds, it can be a very dangerous thing. It can be controlled, but it is not easy.

Every motorcycle ever built can experience a wobble BTW, which makes me think that this news story (I saw the ad too) is basically filler sensationalism.

Racing bikes have dampening systems designed to mitigate wobbles, and it is possible to buy after market dampening systems for Harleys (and other bikes too). For Harleys though, the wobble is not a big giant issue at legal freeway speeds and as long as your bike is in well maintained condition (tire pressure and wear are major contributing factors), you should never experience the problem.

Don't drink the Koolaid.
 
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Old 05-16-2011, 02:04 PM
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What network has the "news"?
 
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Old 05-16-2011, 02:06 PM
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Not having your forks tight enough will cause it also. For 5 years I have had a slow speed wobble and no one could figure it out. A new Wrench fixed it the first time he drove it.

The vibration thing is true above. I been there done that. Very dangerous but not likely most will experience it. Do not brake or use throddle if you get a wobble. Let the bike slow down on its own and ride it out.
 
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Old 05-16-2011, 02:43 PM
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Originally Posted by csbreeze
Not having your forks tight enough will cause it also.
Yup, though wear affecting the torque on your steering head nut should not be noticeable unless you have a high mileage bike. Regardless, checking the torque should be done pretty regular. Not sure what the recommended frequency is.

I did a Google on the Harley wobble, which brought up the swing arm issue that the pre-2009 FL frame had with rear wheel steering in turns and its relationship to Harley's engine isolation system. I do not know if other frames have the same issue.
 
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Old 05-16-2011, 03:51 PM
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I get that wobble at about 100mph.... That's when I know ts time to slow down!

Speed up or slow down and it stops.
 
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Old 05-16-2011, 04:05 PM
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Originally Posted by keith_stepp
Yup, though wear affecting the torque on your steering head nut should not be noticeable unless you have a high mileage bike. Regardless, checking the torque should be done pretty regular. Not sure what the recommended frequency is.

I did a Google on the Harley wobble, which brought up the swing arm issue that the pre-2009 FL frame had with rear wheel steering in turns and its relationship to Harley's engine isolation system. I do not know if other frames have the same issue.
My wife saw something about the pre-2009 "death wobble". She now wants me to trade-in my '08 for a 2012 in a couple of months.
 
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Old 05-16-2011, 04:10 PM
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Reminds me of how I used to get going down hill on a skateboard and it would start to shake like crazy. Hope to never experience that on my bike.
 
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Old 05-16-2011, 04:14 PM
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Originally Posted by 10ring
My wife saw something about the pre-2009 "death wobble". She now wants me to trade-in my '08 for a 2012 in a couple of months.
"You're absolutely right, honey. I'll get the '12 if you insist. Thank you so much for watching my back."
 
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Old 05-16-2011, 04:21 PM
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Originally Posted by baldu
"You're absolutely right, honey. I'll get the '12 if you insist. Thank you so much for watching my back."

Does she also know that the CVOis more stable?
 


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