Death wobble (speed wobble, wiggle) is a condition when your vehicle shakes or oscillates uncontrollably. This can happen in a variety of vehicles and for several different reasons.
Bicycle/motorcycle/trike – Death Wobble happens when the front handlebars swing uncontrollably from side-to-side. This tends to happen because these vehicles don’t have much positive caster built into the front suspension.
Cars, Jeeps & pickups – Death Wobble can be caused by loose components but can also be caused or exacerbated by excessive toe-in adjustment of the front wheels. If the vehicle has lifted or altered suspension, the change in the angles can allow a small change to cause a larger than normal movement in the steering. Sometimes hitting a bump or pothole will start the vibration. Sometimes slowing the vehicle down will cause the vibration to stop.
Trailers – When towing a trailer, Death Wobble can occur if the trailer is loaded with insufficient tongue weight.
Today I saw not one, but two pickup trucks pulling trailers that were miss loaded and they were just on the verge of death wobble. They were going down the freeway, probably 45-50 mph; I didn’t have a chance to get the phone out to video capture these examples. These people are out there and they’re driving next to us, it’s scary.