Tank slap happy

My bike likes to try to tank slap when I go over 70,what is wrong?

Could be a lot of things:

- Tires
- Steering Head Bearings
- Suspension Setup
- Luggage
- Wheels not true

txstroker wrote:

My bike likes to try to tank slap when I go over 70,what is wrong?

You need to supply much more information.

What tires are you running? Front and Back
What air pressure? Front and back.
R or X ?
What mods have you made?
Bike ever been in a wreck or accident?


I have a 2008 wr250x and I've had her max'ed out at 85 mph a number of times. Never had tank slap.
When I had Distanzia tires on there was a little wobble over 80 mph, but never a tank slap.

What does tank slap mean?

wristpin wrote:

What does tank slap mean?

Are you asking OP to describe exactly what happened to him?

Or are you asking what a tank slapper is in general?

txstroker wrote:

My bike likes to try to tank slap when I go over 70,what is wrong?

Are you sure you're using the term correctly? Tank-slapping is a very violent event, almost always leading to a nasty crash. You most probably are experiencing a speed wobble, which could be due to a number of factors like suspension setup, tyres, tyre pressure, loose or worn bearings, etc.

Try the easy things first: check your tyres for proper installment, and change tyre pressure to see if speed wobble is affected. Then check wheel and head bearings.

Have you raised/lowered rear or front suspension?

I've never heard that term before, just wondering what it means.

wristpin wrote:

I've never heard that term before, just wondering what it means.

You can get a pretty good idea from this:

.

Mind you, many of these depicted are not really tank slappers.

And don't be encouraged by the fact that almost none of them ends up crashing: they save it because they are the best riders in the world. If something similar would happen to any of us, we would end up dead.

Tank slapping is the violent oscillation of the front end in which the entire front wheel and suspension and handlebars start "wobbling" from side-to-side and in some cases the "wobble" gets so bad the front end is going from lock to lock. So on something like a sport bike the hand grips are in fact almost slapping the gas tank from one side to the other very quickly or violently as another poster put it.

This is why steering dampers were invented.

Youtube search "tank slapper". You'll see plenty.

In many cases guys are setting the bike's front wheel down from doing wheelies and the front tire comes down slightly askew causing the bike to convulse.

Under hard acceleration when the front end is getting very light a small bump in the road can cause an oscillation as well especially if you're coming out of a corner and still slightly leaned over.

motokid wrote:

This is why steering dampers were invented.

Could be one of the reasons my WRR is solid on the expressway - I have a Scotts Damper.