Harley Speed Wobble, Tank Slap, also known as the Death Wobble

[alegalsolution]

I don't know if what I experienced qualifies as an official high speed wobble, but here is what happened.

While riding on a freeway at 70mph, on my 2007 Road King Classic without a windshield, I had an uneasy feeling because my front wheel seemed very light and I had some slight wobble/shimming in the front end. As I slowed it went away and the steering head felt normal, but as I increased speed it happened again. Since then I have not had it happen and I have not yet added a stabilizer.

One point worth noting is that the freeway that this occurred on had grooves in the road that ran parallel to my wheels. I have been on other freeways (at speeds of 70-90mph) that have no grooves and I have not experienced this wobble/shimming. I'm still looking for the best type of stabilizer to purchase and install so any advice is appreciated.

 

[R_W_B]

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One point worth noting is that the freeway that this occurred on had grooves in the road that ran parallel to my wheels. I have been on other freeways (at speeds of 70-90mph) that have no grooves and I have not experienced this wobble/shimming. I'm still looking for the best type of stabilizer to purchase and install so any advice is appreciated.

Those grooves will make most any bike experience some wobbly feeling, I know they do on my Dyna at any speed depending on their depth etc.

I don't think I have ever had the death wobble and definitely never had the Tank Slap.

 

[roadglide07]

I've not had that problem on my road glide but I did own a Honda Valkrie Interstate which comes with a handle bar mounted Bates type fairing. The only way I could stop the wobble was to slam on the back brake sliding the rear tire and at the same time applying extreme pressure to the front brake. I then released both brakes and applied full throttle. The bike then came out of the the wobble. I was on a freshly paved road and had new Avon tires. It is my belief that the wind and the fairing created the problem.

 

[StreetGlide06]

Ok, New to the Harley world. I just bought a 2006 Street Glide with 2100 miles on it last week. I have not been on a bike since 1999. I Convenced my wife to get one so we can ride with our friends. Is this something i am going to have to worry about riding down the highway. We are suppose to ride this weekend down I-71 to a bike show. Sorry it just makes me nervouse to hear of this problem.

 

[IBA Harley]

No, you shouldn't worry about it... It is a rare problem, when it occurs... With the low miles you have on that 06, your bike will be rock solid... Most tank slaps occur because the frontend is loose (steering stem bearings, wheel bearings, shocks wore out, that sort of thing), you'll be fine ... Enjoy your ride... Take care... T

I was with you TBone on your last discussion of this, but take exception to this one. My 2004 Ultra had the problem from day 1. Brand new, right out of the box. Scared me senseless... since I was used to rock-solid cornering with my previous bikes. I resolved it by adding a stabilizer that linked the engine/transmission from the transmission case to the frame. No more wobble, no more fear in corners. It's been fine ever since. I also think it's more geometry than weight since you never hear of Goldwings with this issue and they certainly weigh as much, if not more, than my Ultra. Anyway, I think it's geometry... and frame stiffness... plus those bushings in the swingarm... plus the engine mounts. Truly, a multi-factorial problem.

:bigsmiley30:

 

[AZEqualizer]

I haven't experienced any problems with my Dyna as of yet, but I always check my bike like a fighter pilot does before he goes out.... not that this is a sure thing to prevent any problems but it sure doesn't hurt. I'm thinking I will go ahead and spend the bucks on a True-Track for it though...

When I was in law enforcement (which I have since retired from) I had to go through the motorcycle pursuit course - this was mandatory since I was a supervisor (SGT) and might have to fill in for one of the motor officers. It was a good thing I had the training because it probably prevented me from getting seriously injured in a incident I had with a friend's 1982 Honda CB900C.

He had just driven his bike from Florida to Arizona after breaking it in. When we met he asked me if I would check his bike out. He told me that the bike felt weird when it was in high gear (this Honda had a jack shaft transmission -kind of like an overdrive) at about 65MPH under acceleration.

I check the bike out and couldn't find anything loose or any weird tread patterns. I took the bike out and couldn't duplicate it until I tried entering a freeway from an on ramp and hard accelerated the bike to 65MPH. At this point all of a sudden the front end started to wobble and the bike tried to sway side to side. I backed off the throttle but the bike continued to get more sever in its action until it eventually caused the bike chassis to dump right and left hitting the pipes on the sides. When it felt like it was starting to endo I forced the bike to lay down on its side and rode it down the road until the force started to lift the bike to allow it to go end over end. I kicked off and slid down the road watching the bike go end over end a couple of times. Long story short - the bike was towed to a dealership where they said basically the steering steam bearing self destructed. Unfortunately when my friend went to get the parts so he could persu this with Honda... they had 'accidently' been thrown out. Lucky for me I just lost some skin. Bad for me it was early summer and I wasn't wearing leathers (too hot) and they didn't make the cool suit body armor back then.

Don't know if that was the true problem or part of a design flaw that caused it to happen - don't ever want to go through that again. Funny that was the last year they made that model.

 

[R_W_B]

T, my hats off to your son (or daughter?) and also AZEqualizer's service in LE. I rode in a PGR ride yesterday that was police escorted thru and then out of Kissimee (about 20miles) and then they turned us loose at the interstate.

Those guys know how to ride and handle two wheels at high speeds and intense situations. I could tell just from watching them fly past us to get to the next intersection before our formation got there, that these guys have serious riding ability.

There was other traffic to watch out for but those guys (and gals) are real pros. I have a lot of respect for Law Enforcement in general and even more so for the two wheeled experts of their ranks.

You are correct on the descriptions of slap and wobble. Wobble can be riden thru without going down in most cases. Slap on the other hand usually results in the bike going down.

I've often wondered if those long raked choppers ever had slap, in other words if the longer rake would not be subject to the slap syndrome as much as the shorter rake.

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Regards all Boo

Did you sell your older bike bartheboo? I see you don't have many posts yet. Don't take the edit personal, it has happened to many of us in the beginning. There are certain words that are not allowed here. Get a good synonym finder on your favorites link and you will do fine.

This forum has some good folks on it and a lot of knowledge.

I've heard the newer HD's don't have the wobble issue, ( I think 2009 and up they changed the frame and maybe stiffer mounts).

 

[R_W_B]

My daughter is the LEO, been on the force for 10 years... Actually, long front ends or more angle to the rake makes the bike more stable at high speeds... Dragbikes have 38 + degrees of rake just for that reason... LOL plus the guys that ride those type of Choppers aren't the speed demons so the odds of them every having a tank slap is pretty small... And your right about motor officers, them folks can ride a MC... I'd love to go thru their course, I've gone thru a similar type but not as intense as they do...

That's what I was thinking but did not know. (looks like your edit left off the / in the quote ending BTW)

Anyhow watching those cops ride was impressive. Half of um were on HD's the other half looked like BMWs but they were going to so fast I could not tell. I guess one were police and the other were County sheriffs.

 

[AZEqualizer]

Thanks for the Welcome -
I haven't come across any stability problems as yet with my Dyna but I still will probably add a True-Track. I do have Progressive fork springs and progressive rear shocks on the bike as well as the new Michelin -Harley Scorcher tires.

As far as stability on choppers - I remember during the blue laws in Mass and not being able to get a adjustment bolt for my Sportster I was loaned one of my friends bikes for the weekend. He had a Indian with a suicide shifter on it, along with a 8 inch out 'Springer' and monkey bars. I remember taking my hand off the bar to shift into second was always such a treat since the front end would wobble and I would feel a lot of anxiety until I got my hand back on the bars. As long as you had your hand on both grips it wouldn't feel wobbly. Heck I was a kid and just thought it was me.

 

[armyvet]

Sorry for your loss. I had this happen to me on a honda last year. I almost hit a heard of Deer. I put both brakes on and the rear of the bike kicked out to the left some. after I released the brakes the bars started slapping left and right. I slowed to about 40 and it stopped. There was nothing I could do. I had to ride it out. I was lucky. The road was wet and my speed was about 60 before the event. The bike was slightly sideways. Thats brought on my wobble. Sorry again for your loss.