How Mountain Bike Suspension Works

Matching MTB Suspension Systems to Riding Style

May 13, 2009
Helen Smeaton

Mountain Bike Suspension Fork by Rockshox - Wiggle.co.uk

Understanding how mountain bike suspension works allows a rider to match the type of suspension system required to his style of riding.

Most mountain bikes come with either front forks or both front and rear suspension systems. The need for suspension is often debated but whether it is necessary or not, a strong demand exists.

The reality is that MTB suspension makes for a more comfortable ride and, when the going gets rough, it can assist the rider through obstacles that would otherwise leave them earthbound. That ability enables a rider to take on more challenging rides and to extend the levels of their technical ability.

This article looks at mountain bike suspension on front forks.

Mountain Bike Suspension

Suspension systems come in all shapes and sizes but have two things in common; some form of “spring” and some method of “damping.”

Understanding the “spring” is easy. This is the element that compresses or squeezes when it hits a bump in the track taking the knock out of the bump for the rider. The “damping” on the other hand takes the bounce out of the spring. An undamped spring will compress as it hits the bump but will then expand rapidly to its normal length. Uncontrolled, that expansion could be fast and violent enough to throw a rider off his bike.

Mountain Bike Forks

The spring in the modern front suspension fork is generally a metal coil or air or a mixture of the two. The strength of the spring is dictated by the weight and riding style of the rider.

Metal springs can be changed for harder springs or some forks have a wind-down mechanism which partially compresses the spring making it slightly harder to compress further. Air springs are generally lighter and are beefed up by simply adding more air to increase the pressure in the system making it harder to compress.

Whilst the strength of the spring is important many riders are more concerned by the “length of travel.” This is simply the measurement of the amount that the spring will compress under maximum load expressed in inches or millimeters. Let’s say a bike has a spring with a length of 120mm. When fully compressed the spring measures only 40mm. The compression then is 80mm and this would be termed 80mm of travel.

Top End Mountain Bike Fork Brands

Good quality forks from brands like Fox and Rock Shox have several adjustable parameters:

Spring adjustment. The ability to make the spring harder or softer.
Rebound adjustment. The ability to control and adjust the rebound in the damping system. That is the speed at which the spring expands (rebounds) to its full length.
Travel adjustment. The ability to control how much the spring can compress i.e. its length of travel.

How Much Travel is Required on a Mountain Bike Fork?

The amount of travel and quality of the suspension fork will depend on a rider’s intended use and riding style:

All action heroes throwing themselves down mountain tracks will want strong long travel systems which are capable of dealing with bigger bumps and hits on the way down.
Touring or cross country riders will need lighter shorter travel forks to make longer days in the saddle more comfortable and to offer a bike which is more capable of climbing hills.
Or simply choose one of the popular fully adjustable systems which allow a rider to switch between short and long travel. The hooligan in the rider can throw the bike downhill then simply adjust the set-up to make it easier to ride back up the hill.

Which Mountain Bike Suspension System?

Match the amount of travel required to riding style and understand the difference between metal and air sprung systems to choose the right mountain bike fork and rear suspension if required.

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