How to Know if Your Motorcycle's Suspension Needs Replacing?

Service manuals will cite specific lengths of time (hours/months/years) or mileage as to when your suspension should be serviced, but the interval will vary widely depending on the type of motorcycle you own and its use case. For example, a sportbike may call out for its fork oil to be replaced every 10,000 miles or once a year. Meanwhile, a relaxed touring motorcycle may recommend servicing every its fork every 50,000 miles, yet a high-flying motocross bike could cite a mere 40 hours for a fork service.

As your fork and shock repeatedly move through their respective strokes, the internal components such as seals, O-rings, oils, pressurized gas (if applicable), and bushings will wear out. The wear from those components will shed particulate matter into the oil, which combines with contaminants that make their way past the seals and into your suspension. Over time, this will cause the suspension fluids to lower their viscosity and reduce damping performance.

The general rule of thumb for the average street rider is that your fork and shock should be serviced every two years, regardless of mileage. The extent of the service will depend on the condition of the internal components, but you should at least replace the oils if the other components look healthy. Service is also a broad term since it could mean refreshing fluids or a complete overhaul, which includes all seals, bushings, and more.

Again, if you're racing, riding off-road, or riding more aggressively, you'll likely need to service sooner than the average rider because you're putting your suspension under greater stress. A professional race team will likely service their fork and shock after every race meeting. That's an extreme – stick with two years, and you'll probably be fine.

Signs Your Suspension Needs Servicing

Most riders are intimately familiar with their motorcycle, and even the most subtle changes in chassis behavior will raise eyebrows. If you've been happy with your bike's suspension and things suddenly don't feel right without you making any adjustments (if applicable), you might want to take a keen look at each end of your bike.

First, let's discuss a few symptoms of suspension that have outlived its service life. Many of these symptoms will share root problems, with aged-out fluids and seals failing often being the usual suspects.

Bouncier ride: A bouncier ride is a common symptom of worn-out suspension. As the fork and shock internals wear, you may experience harsher ride quality over bumps since the suspension no longer absorbs hits as effectively as it once did. Conversely, this symptom is often seen alongside suspension that no longer adequately manages damping rates, resulting in a bouncy ride over any bumps or undulations. Typically, this usually points to fluid that's old, thin, and no longer effective. If this problem has onset rapidly, then a leak is a more likely cause.

A Change in Chassis Behavior: Controlling chassis weight transfer when braking or accelerating is a top priority for your suspension. As your suspension wears out or if components fail outright, you may be faced with a situation that causes the fork to dive excessively under braking or an unusual amount of shock-squat under acceleration. If that's the case, you'll want your suspension examined.

Strange Tread Wear: Worn-out or improperly setup can have a profoundly negative impact on tire wear, causing cupping, scalloping, or tears. Consider this: Suspension that loses its damping ability may compress or rebound erratically and won't maintain a consistent contact patch. Likewise, suspension setup too firm may cause premature wear, such as tearing.

Wear and Tear/Leaks: Remember, folks – your motorcycle's fluids belong inside the bike's components, not outside of them. Conventional suspension is a simple hydraulic system; without oil, you rely on the spring to do everything. That means things will get springy – heh. A sure sign you have an issue is oil running down one of your fork stanchions or a shock shaft. Sometimes, a bit of debris will tear the seal, or it just wore out. If so, it's time to replace the offending seals and replace the fluid.

When Should You Replace Suspension

Now we're getting to every motorcyclist's favorite subject – replacing and upgrading. When doing a complete service on your suspension, you may be given an opportunity to upgrade your fork or shock with something more suited to your needs as a rider. Let's discuss that subject and when it might be the right call.

Many motorcycles are equipped with cheap, non-adjustable or semi-adjustable suspensions that provide adequate ride quality. For example, prior-generation Harley-Davidson touring motorcycles utilized shocks that provided a harsh ride on anything but the smoothest surfaces, as noted in our 2020 Bagger Battle: Harley-Davidson Road Glide Special vs. Indian Challenger Limited. In cases where riders aren't happy with stock suspension performance, looking toward the aftermarket when it's time to service isn't a bad choice, especially if the service will be a notable cost.

There are other times when suspension needs replacing/upgrading, like when the rider can't make the current setup or range of adjustment work for their size or skill level. For example, a rider could be entirely too light or too heavy for the spring rates, and in that case, a set of springs suitable for the rider's weight range should be installed. Likewise, a rider could require a wider range of damping than what's offered and opt for aftermarket solutions that provide such features.

Many of these concepts tie directly to performance needs. As your skill, experience, and pace increase, riders may outgrow their suspension, as is often the case with lightweight sportbikes. In most cases, aftermarket suspension will offer full adjustability and allow much more control over chassis behavior. In any case, upgrading the suspension will typically result in improved handling characteristics, better balance, and greater rider confidence.

There you have it, folks. Your motorcycle's suspension plays a critical role in every aspect of your bike's handling, so we should do our best to maintain it and understand when to service it or upgrade it. Have any more questions? Drop them in the comments section below.

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