wobble - Star Motorcycle Forums: Star Raider, V-Max, V-Star, Road-Star Forum
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post #1 of 15 (permalink) Old 02-21-2018, 06:03 AM Thread Starter
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wobble

I saw a video where a biker lost control of his bike due to an extreme wobble of the front wheel. Is this a common occurrence? What are the causes?

1999 V-Star 650 Classic
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post #2 of 15 (permalink) Old 02-21-2018, 06:23 AM
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Tank slappers. It's probably easier explained in this wiki. https://en.m.wikipedia.org/wiki/Speed_wobble
Usually a steering stabilizer and good tire condition can help in eliminating this issue.
Charley davidson bikes were having a death wobble issue and in fact so bad that the California highway patrol passed on purchasing them after doing road tests confirming thier instablity.
https://youtu.be/sEMojGzG4sk

https://youtu.be/Gmw6QppXnEY
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post #3 of 15 (permalink) Old 02-21-2018, 06:25 AM
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Slack or worn steering, swing arm or wheel bearings, tires with irregular wear patterns or just plain used up, loose or incorrectly mounted accessories that redistribute weight or change aerodynamics in a bad way, rider inexperience... plenty more reasons but I think those are probably the most common.
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post #4 of 15 (permalink) Old 02-21-2018, 06:29 AM
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Originally Posted by road_slug View Post
...Charley davidson bikes were having a death wobble issue and in fact so bad that the California highway patrol passed on purchasing them after doing road tests confirming thier instablity...
Yesterday I watched a video of a Sportster 72 owner who experienced the supposedly common for that model death wobble and he showed that a spoke was missing and that the others were loose. However what was very apparent was that his swing arm had substantial side to side movement as well.




An interesting bit of media frenzy.

Last edited by Diogenes415; 02-21-2018 at 06:41 AM.
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post #5 of 15 (permalink) Old 02-21-2018, 06:51 AM
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Slack or worn steering, swing arm or wheel bearings, tires with irregular wear patterns or just plain used up, loose or incorrectly mounted accessories that redistribute weight or change aerodynamics in a bad way, rider inexperience... plenty more reasons but I think those are probably the most common.
Excellent point. All contributes to front and rear wheel alignment and not in a straight line.
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post #6 of 15 (permalink) Old 02-21-2018, 10:11 AM
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Those that have experienced the 'death wobble'. What have you done to get rid of while riding at that moment?

I ask because I have never experience on a motorcycle. But, did on a bicycle. It stopped by tossing my over the handlebars. Making me go ass of tea kettle. Luckily, I came out relatively unharmed. A bump on my head. Some nice road rash. Mostly, my pride was hurt.

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Tank slappers.
I have never heard of it referred to it as that.

No matter what you ride. Just ride!
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post #7 of 15 (permalink) Old 02-21-2018, 10:26 AM
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there are two forms of tank slap, a low speed wobble and a highway speed wobble.

If you want to see it at the highway speed, put a couple hundred pounds of junk on the back of your bike, and a big windshield on the front, and hit about 88 mph.

The weight on the back shifts the center of balance towards the back wheel, and the windloading on the windshield further tries to lift up the front wheel.

How to stop tank slapping when its happening is talked about all over the internet, but its best to prevent it, because it happens so fast you have very little time to think or react.
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post #8 of 15 (permalink) Old 02-21-2018, 12:43 PM
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From my experience on tank slappers, which was many in 70s and 80s sport bikes, there are two ways to ride out of situation. First, recommended, slowly ease off throttle, very slowly, no sudden closing of throttle, no front brake. Using this method you will slow down slowly getting below the oscillating speed. Second method, used when I was young and dumb, FULL throttle, drive through the oscillating speed. The geometry of bikes have greatly improved and tank slappers are not a major issue these days. I've had the bars jerked out of my hands before on early sport bikes. Used to be the first addition to my new bike would be a steering damper. The bike manufacturers addressed and fixed these issues with better frames and geometry. KCW is correct on proper weight distribution.

2001 Vstar 1100 Classic (sold), Cobra Slash Cut full exhaust, Dropped 1 inch with lowering links, ORK, 4.5 inch handlebar risers, Ultimate passenger seat, Passenger pegs moved forward 4 inches, Handlebar clock, KN air filter, Viking saddlebags, Additional rear lighting
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post #9 of 15 (permalink) Old 02-21-2018, 01:53 PM
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Has anyone with a V-Star reported any wobbles?

-Mike
2014 V-Star 1300 Deluxe, Bag guards and trim rails, Custom Dynamic LED tail/turn, Signal Dynamics BackOff module, Pathblazer headlight strobe, Yamaha Passing Lamps, E.D. Pass seat. Memphis Shades lowers, O2 sensor by-pass.
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post #10 of 15 (permalink) Old 02-21-2018, 02:18 PM
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I have over 50k on my 1100. No wobble ever. I driven slow, fast, and everything in between. With windshield and without. With loaded tall tail bag loaded down. With passenger. In major side wind. In frontal and tail wind. On grooved concrete. On asphalt. Dry roads, wet road. In other words just about every situation that might cause a wobble. My Vstar is a very stable bike at all times. I would say it's the most stable bike I've ever owned. I do check tire pressure and condition very often. I also do what I call a nut and bolt check at least once a month, I check all fasteners for tightness. I commute daily and many pleasure day trips.
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2001 Vstar 1100 Classic (sold), Cobra Slash Cut full exhaust, Dropped 1 inch with lowering links, ORK, 4.5 inch handlebar risers, Ultimate passenger seat, Passenger pegs moved forward 4 inches, Handlebar clock, KN air filter, Viking saddlebags, Additional rear lighting
Loose nut "me" behind the bars
2006 Harley Electra Glide Ultra Classic

https://sites.google.com/site/vstar1100kb/home
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