A steering damper, also called a steering stabilizer, is essentially suspension for your steering. Just as your fork and shock control the vertical motion of your wheels, a steering damper regulates the motion of your front end’s side-to-side movement. It even uses the same technology that’s inside suspension, namely oil passing through orifices. That restriction to flow creates the damping that controls how fast the front end turns.
There are a bunch of different kinds of steering dampers out there, from radial ones that mount to the top triple clamp to linear units that mount to the bottom of the triple clamp. There are even electronically controlled stabilizers that vary the damping based on the bike’s speed. Regardless of the style or location of the damper, they all do the same thing, and that’s slow down your steering.
Most riders like a bike with light, easy steering, so why would you want to slow down how fast your front end turns? Two words: Tank slapper. If you hit a bump that deflects your front tire, or if you’re accelerating hard enough to float the front wheel and you set the tire down at an angle, the front end’s trail can whip the wheel back toward center. If you’re going fast enough and the wheel is turned far enough, the inertia of the front end’s self-centering movement can throw the wheel past center in the opposite direction and set off a chain reaction that can end very, very, badly.
Not sure what I mean? Search for “tank slapper” videos and prepare to wince. Tank slappers are some of the most violent, terrifying crashes in motorcycling.
Steering dampers help prevent and interrupt high-speed front-end oscillations, but for the most part they don’t inhibit slow-speed steering. That’s because of the circuitry in the damper, which, like a damper-rod fork, is rate sensitive. So if you’re turning the bars slowly there’s not much resistance, but crank on the bar quickly and the resistance ramps up.
You mostly see dampers on 600 and 1000cc sportbikes because they’re the most susceptible to wobbles and tank slappers. Lots of power, short wheelbases, and steep steering geometry all improve handling at the sake of stability and make a tank slapper more likely. Lots of off-road bikes use dampers too since they’re ripping across uneven terrain that can deflect the front wheel. You don’t see them on cruisers because those bikes’ weight, fork angle, and other factors make them unnecessary.
So stability and safety is a concern when it comes to steering dampers, but so is personal preference. Some riders just like dampers because they can make a bike’s steering smoother and more controlled, or they see it as cheap insurance to keep their bike from freaking out at speed. Style is a big factor, too, and plenty of people just like the look of a damper and will install one even if their bike or riding habits don’t warrant it.
Here’s a tip though. If you bike has started handling oddly or gotten unstable, don’t bandaid the issue by installing a steering damper. A motorcycling traveling in a straight line is inherently stable, so if your’s ISN’T, you should be looking at your tires, steering head bearings, and wheel alignment.