Most road bikes these days rely on carbon forks to absorb vibration. They’re simple, and require little in the way of maintenance. Mountain bikes need more, relying on fully-loaded shock absorbers that are capable of taking big hits over and over again. Mountain bike suspension service has come a long way with the first shocks being made with rubber elastomers and springs. Contemporary front suspension typically relies on air and oil to cushion the ride.

Fork Anatomy

The typical front fork is comprised of two struts that connect the front wheel to the frame’s head tube. The exception is Cannodales “Lefty” that has only one strut. The distinction of “fork” is due to the steerer tube emerging from the top of the struts, giving it the appearance of a fork. The steerer tube joins onto the “crown.” The “stanchions,” are the shiny parts of the fork that travel inside the “sliders.” The sliders have the traditional dropouts that connect the assembly to the wheel axle.

Aftermarket Shocks

If you’re servicing or otherwise have questions about your fork, your bike’s manufacturer may not have the answers you’re looking for. Bicycle manufacturers don’t make their own suspension products. Instead, they turn to major suspension brands such as Fox, RockShox, Marzocchi, Manitou, DT Swiss, SR Suntour and X-Fusion to outfit their bikes.

About Brakes

If you’re thinking about the compatibility of a new fork, take into consideration that it may or may not work on your bike. Most modern mountain bikes now employ disc brakes. If you want to replace a fork that has rim brake mounts, your choices will be limited to some very basic suspension models unless you upgrade your wheels, brakes, and frame which must have the correct mounts for each type of brake.

Vertical Travel

Mountain bike frames are designed to work with a suspension fork featuring a specific amount of travel. Travel refers to the distance the fork will move before it’s fully compressed.  Suspension travel equals the distance the wheel travels vertically. Before replacing any fork, consider that it could drastically change the way your bike handles.

Some Sizes

Older mountain bikes may have an 80-mm fork, which has went the way of the dodo bird. A 100-mm fork may be an acceptable replacement, but a 120mm fork will likely alter the bike geometry enough to make the bike harder to handle. Always check with your bike manufacturer for replacement fork recommendations.

Lockout Valve

Lockout is the ability to turn a shock off or make it inactive. The lockout is typically accomplished by turning a dial or moving a lever. Lockout is useful for riding on flat ground or going uphill when the constant compression and decompression of the shock wastes energy.

Damping Control

Damping is probably the single most important feature of a suspension fork. Damping controls the speed at which the fork moves up and down. Damping provides the rider with increased control, comfort and safety through rough terrain. Damping is usually accomplished by forcing oil or air through a small hole or port, but some very basic forks use only friction between the upper and lower tubes for dampening. Without damping, energy from impact would compress the shock immediately and then shoot the fork up again in the blink of an eye.

Damping Adjustments

Most forks rely on external knobs to adjust damping rate. Turning external knobs clockwise increases the amount of damping. Internal adjustments are also possible, but not as easy. Internal  adjustments include changing oil viscosity for slower or less dampening. Most serious mountain bikers prefer to fine-tune damping to provide the best possible performance for their weight and riding style.

Mountain Bike Suspension Service – Fork Care

As far as bicycle components go, suspension forks are relatively complex things as there’s a lot going on in there. Basically, the more moving parts, the more maintenance required. Servicing suspension forks is vital to keep them operating smoothly.

Mountain Bike Suspension Service – Oil Changing

Changing the oil in your fork requires special tools and supplies that you probably don’t have in your garage. Seals can get damaged or fail to seat properly. Servicing a fork to this degree should probably be done in a bike shop unless you’re experienced.

Mountain Bike Suspension Service – Do It Yourself?

Full servicing can be carried out at home if you’re experienced, and have the tools. It involves removing the lower legs or sliders, cleaning and inspecting the seals, stanchions and bushings before topping off the oil and re-assembling the fork. Before attempting any work or opening the fork, make sure you release any pretension or air pressure.

Mountain Bike Suspension Service – How Often

Most manufacturers recommend  changing the lubrication oil at least every 30-50 hours, and doing more extensive damper overhaul once a year. Other manufacturers recommend cleaning and changing the oil every 25 riding hours and a full service every 200 hours. Full-blown servicing is recommended at least once a year by most dealers, but it also depends on what type of fork, how you ride and where you ride. The three things that will affect the service interval and performance of your fork are water, mud and dust. How much you use your fork in those conditions will determine how much servicing it requires.

Mountain Bike Suspension Service – Simple Lube

How Oil Lubricates

Mountain Bike Suspension Service – The Take Away

The take away with mountain bike suspension service is to stay ahead of it and replace the oil and seals before they need completely replaced as if you wait, this can cause damage and the potential for needing a new front fork. Take note of how you’re riding and what conditions you’re in and if you can’t do the servicing on your own, take it to a local bike shop who knows there stuff. They’ll be able to do a complete overhaul and guide you in when next to bring it in.