How To Avoid A Tank Slapper or Speed Wobble

When the handlebars wildly vibrate, it’s called a tank slapper. They’re also known as speed wobbles or death wobbles, and they may be deadly, as the latter term indicates.

They are frequently created at a high rate, as shown in the video below.

It’s a compelling incentive to always wear appropriate motorcycle safety equipment.

It’s an “underdamped torsional oscillation of the front wheel/suspension that may be set off by either a road input or input from the rider’s weight causing a steering moment or even a gust of wind,” according to racing engineer Jeromy Moore.

It’s for this reason why world speed records are established on flat salt lakes with little wind.

However, as demonstrated in this footage from The World’s Fastest Indian, aerodynamic streamliner motorcycles may develop speed wobbles even on salt lakes.

This is an example of “yaw oscillation,” which is caused by aerodynamic imbalance, most likely caused by a gust of wind, according to Jeromy.

“The entire bike is responding,” he explains, “but no steering damper could help in this scenario.”

“It’s more of a problem of aerodynamic stability, where the tail fins’ stabilizing moment isn’t enough. This is why planes have tail fins: they place the aerodynamic center of pressure behind the center of mass, enabling the plane to return to its original trajectory rather than veering away from it in the event of a side wind.”

How to get out of a tank slapper?

So, if you ever have a speed wobble, what should you do? How do you get back on your feet after a tank slapper? On this subject, the Internet is awash with differing viewpoints. Even professional riders are unable to adequately describe it, and in this situation, the majority of them rely on their gut instinct.

Some advice pinning the throttle and getting the most power out of it.

Some advice turning off the engine.

Some advice applying brakes, while others advise leaving them alone.

Some people recommend holding the tank between your thighs and leaning forwards.

To shift weight to the back, others recommend loosening the hold on the handlebars and sitting upright.

HOW WOBBLES START

When the load is moved to the rear tyre and the front tyre is un-weighted, they most commonly occur on a motorbike at fast speeds.

When the oscillation begins, the front tyre contact patch is offset from the steering axis and attempts to reestablish itself by swinging back the opposite way, according to Jeromy.

Unless a steering damper is installed, the steering overshoots and moves past the straight-ahead position, amplifying the oscillation.

STOPPING WOBBLES

So, what happens if you hit a speed bump?

There are several points of view about this.

Some suggest you should power out of it, while others say you should back off the throttle.

Some advice slamming on the brakes, while others advise leaving them alone.

Some advice holding on with your hands and knees. Others argue that you should lean forwards to lessen aerodynamic resistance and weigh the front wheel, as seen in the British video. Others advise loosening your hold and sliding backward to relieve pressure on the front wheel.

There appears to be little widespread agreement.

However, according to Jeromy, physics dictates that you accelerate and lean back.

“This lessens the weight and hence the oscillations’ movement till you can control it with your arms,” he explains.

“It’s simple to say on paper, but it’s not a natural reaction to want to go faster when the bike beneath you is going wild.”

He claims that catching it in the straight-ahead position is nearly difficult since speed wobble oscillation is recorded at 4-10hz (each change of direction in the handlebars takes from 1/10 to 1/4 of a second).

In actuality, there’s not much you can do to avoid a speed wobble, especially when the bars shake so violently that your hands are thrown off the grips, as shown in the video above. The majority of persons who have had them have also crashed.

Avoiding them is the best approach to stop them.

LOW-SPEED WOBBLES

My Experience with Speed Wobble

It happened within the first month of ownership on my first sportbike, and sure, the bike was in poor mechanical condition. It had a damaged fork seal and a suspension fluid-covered right fork leg.

Yes, I was pushing it too hard on the public road since I was inexperienced.

As you can see, the deck was stacked heavily against me.

My pals and I drove to an isolated lane on a chilly Sunday morning to pop wheelies and snap some great photos. I realize it’s a stupid move.

I noticed an open stretch of road as we were departing and pinned the throttle…

BOOM TANK fu*!ing slapper in first gear…redline…second gear….redline…third gear…and BOOM TANK fu*!ing slapper in second gear…redline…third gear…and BOOM TANK fu*!ing slapper in third That moment when you realize you’ve messed up.

I was completely unaware of what had occurred. I had no idea what a tank slapper was back then. But, happily, I was able to escape.

What exactly did I do? As soon as the handlebars began to shake violently, I trusted my instincts and sat up straight. And, happily, everything came to a close swiftly.

You can’t keep the throttle closed or fully open when the handlebars are wildly vibrating. Keeping your hands off the brake and throttle keeps the bike in a predictable state. The bike should be steady again after a few seconds, and the front wheel should prefer to stay in line.

When it happened, I was fortunate to have a big straight length of vacant road in front of me. It might have happened in the canyons or in the back of a car.

So, I’d think that loosening your grasp and shifting your weight to the back is the best thing to do.

It’s terrifying, therefore it’s better to take precautions and avoid having to cope with motorbike speed wobble. I have discussed how important strong vision is when riding a motorbike.

FAQ

What Causes Tank Slapper?