Over the last decade the main focus of development on mountain bikes has been suspension. Here's what you need to know.

Over the last decade the main focus of development on mountain bikes has been suspension. Paul Turner's Rock Shox suspension forks led the way (aided by a World Championship win by Ned Overend in 1990) and soon numerous manufacturers began to develop front suspension forks and shortly afterwards, suspension in the frame for the the rear wheel too.

Suspension is particularly useful to the off road rider, it provides:
 

• Improved comfort
• Less fatigue
• Better traction for the wheels
• Forgiveness for many handling mistakes!
• Faster riding over rough terrain.

When first released onto the market, mountain bike suspension was really quite crude and very expensive. Over the years though, vast improvements have been made. At the top end of the market bicycle suspension forks are reliable and superlight for cross-country racing (XC) and models for downhill racing (DH) offer over 200mm of travel. At the other end of the spectrum, budget bikes with full suspension offer good value for money.

The suspension market is now massive, with numerous manufacturers, styles and price points. With such a large range of products you can now choose suspension products that are specific to your riding style and needs. This is great but it makes choosing your suspension product that much harder!

Bicycle suspension can be simply divided into:

• Front suspension forks - either fitted on a complete new bike or as an added upgrade to a frame
• Rear suspension - integral to the frame or complete bike.

However, as always, products are made for specialist sub-divisions of the sport, in particular:

• Downhill
• Free riding
• Cross country.  

It is worth spending some time considering your needs when you're choosing suspension products as there are significant differences between these styles and it's worth getting the right one if you're going to get the maximum benefit, performance and enjoyment from your purchase.

The key words to consider are: Travel - The amount the fork can move. This may be as little as 25mm in some models and over 200mm for some DH models. The more travel the fork has generally determine its length. Consequenly DH forks are noticeably longer than those on XC bikes.

Fork type - 'Standard' means two separate moving fork legs attach to top section or 'crown'. 'Double clamp design' means the fork legs are extended and held by a section at the bottom and the top of the headset, similar to the design on a motorbike.

Suspension type - What the fork uses to provide the suspension. There are a variety of ways: simple elastomers (rubber type sections), springs, or air and oil. These may be used on there own or combined, each type has its pluses and minuses but in general the best and generally the most way is to use a combination of air and oil.

Front suspension

Downhill Front suspension specifically for downhill use is designed to give the maximum amount of travel and has to be laterally stiff to help handling. Downhill forks may be a standard style fork but most specialists use the double clamp style which is stiffer, usually heavier, more expensive and have a limited turning circle. 

These forks offer the largest amount of travel possible, (200mm or more), for super comfort and to withstand high speed impacts over rough terrain. Many top models also incorporate a special front hub with an oversize axle to improve the lateral stiffness and handling. Such forks are not suitable for cross-country or general off-road riding as the suspension tends to 'bob' too much on level or uphill grades and the long travel is not suit compatible with some frames.

Free riding

For general riding (or 'free riding') you want a fork that is a compromise between the specialist cross-country downhill units. This will provide with enough travel for to enjoy your downhilling, but without hindering riding on the flat or uphill. A fork with 75-100mm of travel is ideal and there is a wide range to choose from.

If you're upgrading from a rigid fork or one with less than 75mm travel, do check with the supplier that your new purchase will be compatible with your frame. (Measure the length of existing fork blade. If there's more than 15-25mm difference, you'll need to re-think your purchase).

Cross country

These forks have 50-75mm travel and can absorb the majority of terrain obstacles but they will not be as comfortable as a longer travel fork. Very lightweight models are often more flexible (sideways) which can adversely affect the bike's handling. However, they do make off road riding much easier and better models (read 'more expensivE.htm') are both lighter and more efficient for uphill riding too.

Rear suspension

As technology improves, rear suspension is becoming more popular every year - and not just for downhill riders. Originally full suspension bikes were so heavy that they were only suitable for DH riders. However, new designs are bringing lighter, laterally stiffer frames, with more travel to the market and full suspension is now common place in the weight conscious world of XC racing. It's also filtered into 'street bikes' - although a top racing model may cost well over £3000, today it is possible to buy a full suspension bike for under £200. Bear in mind too, that with more moving parts, the suspension bike needs more maintenance and will wear more rapidly than a regular 'hardtail' bike. Downhill  

Downhill frames have a large amount of travel (150-200mm) so that they can absorb the roughest trails at high speeds and let the rider can stay in control. Prices have tumbled (sic), but for the newest and most efficient designs you will still have to spend a lot of money. Added to which, if you really are using the bike 'to the max' you'll want the full length DH forks and you'll probably need to invest in the latest braking system too! Oh, and don't expect to ride uphill with any ease.

Free riding

These are the majority of rear suspension bikes. The newer designs offer a smoother ride and will help you ride faster over rough ground, with better control, less fatigue, more comfort and more fun. 75-100mm of travel is a good compromise between efficiency, comfort and weight. Some models are heavy though and may need some careful adjustment to suit your weight and riding style. But just like models in other disciplines, the newest designs are more efficient, lighter in weight and laterally stiffer but invariably more expensive until something new comes along!

Cross country

These models are specifically designed for fast riding, and in particular, cross country racing. They generally have 50-75mm of travel though some designs have as little as 25mm, by using an elastomer shock in the seatstays and the natural flex of the chainstays (using 'springy' materials such as titanium). Such frames have become known as 'softtails'. These bikes are designed for performance riding. They do not offer great comfort but they ride well uphill and downhill, and the lightest weigh only 400g more than an expensive hardtail frame. Their only downsides are that and some models can be awkward to carry over obstacles and are more prone to mud-clogging, and as always, the best come with the highest price tag.