Motorcycle Weaves and Wobbles: How to Avoid Them and Deal with Them

There are some aspects of motorcycles that motorcycle manufacturers are reluctant to talk about. Weave and wobble are two of them. Either can put you down and hurt you, so you need to know what these things are, and how to prevent their onset. We all know that motorcycles are not inherently stable. When stationary, they require stands to hold them up, and when in motion, they must have a balance of dynamic forces to keep them upright and pointed properly. Should those stabilizing forces become inadequate, motorcycles weave or wobble and sometimes fall over.

Your Harley consists of two main sections, the front and the rear. Everything that moves with the handlebar is the front; everything else is the rear. They pivot around one another at the steering head. Anytime you ride, both parts are trying to wiggle like upset gyroscopes. If the rear wiggles and doesn’t stop, it is a weave. If the front wiggles and doesn’t stop, it is a wobble. The faster you go, the more powerful those weaves and wobbles can become. Speed matters.

This natural tendency to weave or wobble is resisted by friction between tires and roadway. When a wheel is turned from the straight-ahead direction by a pebble, expansion joint or whatever, its tire produces a torque that works to straighten the wheel and everything attached to it. You may notice only a small and very temporary wiggle of the handlebar or seat. Thousands of hours of development and testing are behind making this event a minor one. Stability is a complicated matter.

Every component from the tire to those steering-head bearings must do its part to ensure that the wiggle stops. Steering-head bearings are the most critical and merit special attention; they must be exactingly adjusted; there is no “good enough.” Tires must be properly inflated. Wheel bearings must have minimum play. Spokes must be tight. The rocker bearings on a Springer must be correctly adjusted. Suspension dampers must work properly. The swingarm pivot must be firm. Rubber engine mounts and control links on FLs must be without significant play. More than one bagger has gone down because its control links were worn out, and they can wear out as often as every 25,000 miles. The ship must be tight.

It must also, in critical ways, remain close to stock. Earlier I mentioned that both the front and rear try to wiggle (weave or wobble) when you are under way. They tend to wiggle at a particular frequency. Fronts typically have a frequency of six to 10 complete cycles per second and rears three or four. Harley has tuned its bikes to damp the frequencies of each model. You can easily change these frequencies and get in trouble by doing so.

Anytime you add weight to the front or rear sections of your bike, you change its natural wiggle rate. The effect is very small if the weight is near the center. A piece of lead tied to a handgrip is more destabilizing than if it were tied to the center of the handlebar. Similarly, a weight back up in a Tour-Pak is more likely to lead to weave than if you were sitting on it. (Note: Harley’s Tour-paks and saddlebags are engineered to safely accept specified loads. Pay attention to these limits.)

Aerodynamics also matter. Harley’s windshields have compound curves and allow air to flow smoothly around them. Some of you may remember when the old flat windshields would sometimes cause a speed wobble. Air spilling unevenly around those shields would pump the handlebar from side to side and overcome the bike’s damping reserve. Big square boxes high up on the rear can lead to a weave. More than once, I have stopped a customer’s weave problem by simply removing the box they bolted on the back.

What to do if you get into a weave or a wobble:
Weave:
You can almost always get out of a weave. It’s mostly a matter of knowing what to do and having a little space to do it. I’ve had weaves start when entering corners at high speed and thanks to preparedness I’m still here.
• If you’re cornering when a weave starts, do not straighten up. Going vertical seems to be our gut reaction to any riding emergency. Train yourself not to do that.
• Continue to steer. You still have control of the front and can pretty much go where you need to go.
• Apply the front brake. Apply it as hard as can be done safely. The quicker you lose speed, the quicker the weave stops. A weave is speed dependent; the faster you go the more likely it is to happen.
Wobble:
A full lock-to-lock wobble is very dangerous and usually results in a crash. You cannot steer and your bike will continue in the direction it was headed when the wobble started.
• If there is room and time, gently apply the rear brake. Braking may intensify the wobble but the bike will still slow. Slowing will stop the wobble although the speed at which it stops will be lower than the speed at which it started.
• If you are headed for a wall or some similar deadly obstacle and it becomes clear that you are going to hit it—bail off. It is the better choice. A wobbling motorcycle decelerates at about one-eighth g. A rider sliding along slows at closer to 1 g. You’ll stop sooner and in less distance than the motorcycle.
• Wobbles, like weaves, are speed dependent. They typically begin above 75 mph. However, if the steering bearings are loose, a wobble can begin as low as 45 mph.
Finally:
I have never examined a weaving or wobbling stock Harley-Davidson motorcycle that did not have a fault. Most were maintenance or wear related. A few developed weaves from being loaded improperly.
I remember one Springer that had loose rocker bearings, loose spokes, and loose front-wheel bearings. The owner had paid for service he never received; none of those parts had been touched since they left the factory even though he had paid for a couple of services.
Any number of FL touring bikes have delivered their riders a weave or two because the upper and/or front stabilizer links were worn and loose. Be sure to check yours.
I recently examined a Softail that had been lowered. It was stable until the rider loaded his bags for a cross-country trip. At 75 mph the bike developed a weave and he fell with injury. At stock height and with full suspension travel this accident most likely would not have happened.
Should you be unsure about whether you have a tight ship, have it checked over by someone you trust. Although few of us will experience either a weave or a wobble, I want the number to be zero—please pass the word.

10 COMMENTS

  1. great article, I have experienced a wobble from the same bike twice, it was a Buell Blast I bought on craigslist. the first one I went down going 75 on the highway and again going 40 in town. I figured out that the reason it happened was because I had the head gasket change and they didn’t secure the engine properly.

  2. Awesome article. I’m working on a softail that’s been lowered front and rear. Wiggles like crazy over 60. I believe the front is to low. Gonna throw the stock springs in and see what happens. Thanks. GREAT article.

  3. Worth reading. I’ve been classic racing for many years (mostly 350 & 500 singles) & only ever had little bar twitches over surface changes but I had one massive tank slapper (wobble). It was induced by accellerating when cranked over, front wheel lifting over bump then coming down crossed up due to counter-steering. It was instantaneous – I was shaken to bits & thrown down the road. Walked away but it was nasty. That was a few years back. Recently I’ve been racing a bike that has lairy “wobbles” (feels like it’s happening at the rear rather than bar movement) going into fast bends – possibly triggered by slight change of surface when tipping in to corner. I’m able to steer approximately the right direction & hold throttle slightly rolled off until it eases. These were bends I would take flat in top normally (over 100mph) but the wobbles put me off that! The problem was “cured” by winding the steering damper up full but still left me feeling slightly wary. I feel that the damper is just masking another problem – I previously took the same bend on other bikes without any steering damping. Assuming good headstock & swing arm bearings, I wonder if it might be caused by A; one of the twin rear shocks being faulty, B; frame or swing arm being bent, C; rear shocks mismatched to rider weight – sag etc – not set up correctly, D; front forks not working correctly. I’m hoping to get it sorted!

  4. You mentioned the “frequency” (number of cyclical motions per second) for the front and then the rear wheels. What was measured relative to what, please?

    Maybe, for whatever load and speed range(s), the front wiggles were counted according to the assumption that the rear part of the ‘bike was stable. Then the rear wiggles were counted, assuming that the front part of the ‘bike was stable.

    At some stage/s of riding the ‘bike, did the rear wiggles either add to or subtract from the wiggles of the front wheel?

  5. With my limited understanding of suspension/bike set up, it’s very hard to separate out the front from the rear. Is the front upsetting the rear or vice versa? World class riders might be able to describe to their engineers exactly what is happening but most of us struggle to make sense of any unusual behaviour of the bike. There is also rider input. When accelerating hard riders often try to pull themselves to the front of the bike. The effort they put into that means they’re pulling on the bars which can induce weaving/wobbles particularly if the the bars are wide as there is a lot of leverage then. A small pull on a wide bar will affect how the bike tracks

  6. I find the article hard to believe. If a wobble generally starts at high speed why was Hardly Dangerous the bike mentioned. If the article would have been about oil leaking, poor design or performance, loud and noisy then I would agree that HD is the tractor of choice. I looked forward to reading some great insight to dealing with high speed wobble. Found nothing in this article. Apart from poor maintenance (steering column bearings, tires, balancing, wheels, high speed wobble is cause by the front tire rotating at a different rate than the rear tire. This often happens during hard high acceleration because the rear suspension loads up due to torque and the front suspension becomes less loaded, and may even lift. if at this point the front wheel speed falls out of sync with the rear wobble will be produced. (you see this happen when people catwalk for long distances and then return the front tire to the road). It is extremely dangerous. You have to hope you can ride it out / wait for the front tire to achieve the proper speed. Don’t grab the bars too tightly let the energy dissipate, pinch the tank hard with your knees, and do not initial any speed change.

  7. First thing comes to my mind is on my bike I have a 19” front wheel and a 15” inch rear. So obviously the front will rotate less than the rear. Michael Mororcyle

  8. In response to com enly sense, ( I don’t expect Rider to respond to this 10 year old thread!) you don’t need to be doing 100mph to have wobble/ weave & a HD or any bike can have one at lower speeds given the right ( or wrong!) conditions. HDs have enough grunt to get into trouble. I’ve seen one accelerate over an uneven road, wobble & crash, probably less than 60mph & my tankslap/ wobble crash above was less than 60mph, but in more extreme conditions than most road riders would find themselves. Catwalks/wheelies in themselves don’t initiate a wobble ( witness the 1000s seen safely performed on youtube & televised racing) I agree if you’re saying that a wobble is induced when the front wheel comes down from a catwalk/ wheelie but is not in line with the bike when it touches down. The gyroscopic force turns the wheel to the direction of travel but goes past that to the opposite side & back several times. The rider can’t control it & either crashes or has a big scare. In that sense a wheelie raises the stakes. As you say, holding the bars too tight can definitely increase the risk & gripping the tank with your knees can help

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