Wobble and instability
Distinguish a light handlebar shake from severe wobble, avoid abrupt inputs, and inspect the motorcycle afterward.
Light handlebar shake (shimmy)
A light, rapid handlebar shake often lasts only briefly and dies out on its own. It may appear after a bump or a brief unloading of the front wheel.
Wobble
Rapid, noticeable oscillation of the handlebar and front wheel. The handlebar moves from side to side more strongly and for longer than in a brief shake.
Whole-motorcycle sway (weave)
The entire motorcycle weaves, sometimes with a noticeable shift of the rear. These oscillations are slower than a handlebar shake.
Severe wobble (tankslapper)
Strong, rapid handlebar oscillations with large amplitude. If the handlebar moves sharply from side to side and the oscillations do not die out, a harsh steering, braking, or throttle input can intensify the oscillation.
Tires and wheels
- incorrect tire pressure
- tire wear or damage
- poor wheel balance
- misaligned geometry or wheel damage
Steering and suspension
- steering-head and bearing play
- worn or incorrectly adjusted suspension
- swingarm or wheel-bearing problems
Load and aerodynamics
- heavy top case or load far to the rear
- poor luggage distribution
- nonstandard windshield or fairing
- wind-catching clothing
- heavily unloaded front wheel
Road and front-end unloading
A bump, a series of irregularities, a rut, or a sudden increase in load on the front wheel after it has been unloaded can cause handlebar oscillations. Under hard acceleration, the front wheel carries less load and is more sensitive to such jolts.
Sources · 1
- Motorcycle Operator Manual
Mechanical Problems, pp. 30–33
Used for: How oscillation relates to loading, pressure, fasteners, and component condition.
Open source
Legs and arms
Keep your feet on the footpegs and your knees against the tank. Keep your arms relaxed and do not fully straighten your elbows: do not grip the handlebar tightly or try to stop the oscillations by force.
Don't grab the front brake
Abruptly applying the front brake while the handlebars are oscillating can make the shaking worse. Resume normal braking after the motorcycle stabilizes.
Why adding throttle sometimes helps
On a level, straight road, smooth acceleration can help the handlebar oscillations die out. Under acceleration, load shifts rearward and the front wheel unloads. This refers to rapid handlebar oscillations; slow weaving of the whole motorcycle is a different type of oscillation.
After stabilization
Smoothly slow down and stop in a suitable place. Check the tires, wheels, steering head and bearings, suspension, fasteners, and luggage. If the instability recurs, do not return to high-speed riding until you find the technical cause.
Start with the tires
Check tire pressure, wear, and damage. Then check wheel balance, play in the steering head and bearings, and the condition of the suspension and swingarm.
Check the load
A heavy top case and load far to the rear unload the front end. Redistribute the luggage and make sure the fasteners have no play.
After a hard impact
If the shaking started after a hard bump or impact, inspect the wheel, tire, and suspension. Do not continue riding at high speed until you determine the cause.
Steering damper
A damper reduces rapid handlebar movements and may improve the stability of a particular motorcycle, but it does not fix incorrect tire pressure, play, worn tires, improper loading, or a suspension fault.
Sources · 1
- Motorcycle Operator Manual
Mechanical Problems, pp. 30–33
Used for: Checking the load, tires, wheels, steering, and bearings.
Open source