I-MTB

Enduro MTB Suspension Fork Buying Guide

With Enduro being one of the newer sectors in MTB, manufacturers are now offering bikes with a complete setup that is close to or as close as is acceptable for trail riding and Enduro racing.

One of the key elements of an Enduro or trail bike that rides well, is the front fork. We thought it would be a good idea to highlight some of the features found on suspension forks and discuss what in our experience are the best fork brands and/or feature setups for riding and racing.

The suspension fork is made up of many elements. All working together to give the smooth ride that riders desire.

The suspension fork is made up of many elements. All working together to give the smooth ride that riders desire.

Fork Basics

Most suspension forks have a few key technical features that work together to give you the quality of ride that we are looking for. The leg diameter (stantions), travel, damper cartridge choice, spring type and axle diameter. There are other features that also add into the mix, but for the moment these features are the most significant.

Each brand of fork offers a different mix of the above features, with the aim of making the best fork they can, some brands might be considered to be stronger in one area compared to another. Also now with the emergence of three distinct wheel sizes, the forks are tuned differently for each size.

Here a fork with 35mm legs is maintained.

Here a fork with 35mm legs is maintained, note the larger heavier appearance of the fork.

Leg Diameter

Suspension forks are offered in three main diameters, 32mm, 34mm and  35/36mm. With each size increase the stiffness and often length of travel increases, as does the weight.

For lightweight applications like trail riding or small riders a 32 mm fork is probably adequate, however taking this fork on hard Enduro descents might stretch the performance characteristics too far and give a less satisfactory flexi ride down. Conversely though it will probably be easier to ride up.

Most brands now have settled on the 34mm fork leg diameter as a preference, with stiffness and weight being a good compromise. Rockshox though have recently settled on 35mm, that extra mm giving them a better feeling of stiffness.

For out and out rigidity and control, nothing beats a 36mm fork like the Marzocchi 55 or Fox Float 36.

Here a fork with only 125mm of travel is a valid option for racing in the hands of the right rider.

Here a fork with only 125mm of travel is a valid option for racing in the hands of the right rider.

Travel

This is where things have got interesting recently. The longer the fork the greater the leverage and in theory the greater the potential flex at the sliding join. Most trail and Enduro forks have settled around the 150-160mm of travel mark, which in our opinion is ideal, whatever the wheel size. In theory due to the greater roll over ability of larger wheels less travel is needed, but according to Curtis Keene, even a 29er with 160mm of travel is actually very good. We have heard rumors though that stretching the Fox 34 out to 170mm might be a step too far in performance characteristics, but again some of that is rider preference. We personally prefer a 160mm fork, in general it can be used for any type of riding, and at the same time has all the characteristics that allow a good ride.

Travel adjust is another feature that appears on many forks, it is worth considering if pedaling up steep technical trails, as it can make the bike geometry and rider position better uphill, allowing the rider to transfer more power and be more efficient. However not all riders need this feature and in our experience it is not really essential.

Andrea Bruno a professional Enduro rider uses a 32mm or a 36mm fork to save weight depending on the race he is doing.

Andrea Bruno a professional Enduro rider uses a 32mm or a 36mm fork to save weight depending on the type race he is doing.

Weight

Weight generally follows the fork leg size, with larger legs and also larger axles weighing more. However depending on which type of spring, whether air or a metal coil spring, and oil quantities in the damper system, these elements also affect weight. Marzocchi for instance uses slightly more oil, which adds a few extra grams in their Marzocchi 55, but the increased performance is certainly noticeable.

Jerome Clementz uses a 15mm diameter axle on his Pike fork.

Jerome Clementz the Enduro World Series Champion in 2013, uses a 15mm diameter axle on his Pike fork.

Axle diameter

Most forks use a 15mm or 20mm axle diameter, with the trend now being towards 15mm. Which is best? Well talking to a top professional Enduro World Series rider Curtis Keene, he was adamant that he could not notice the difference between 15mm and 20mm axles. Although he did say for heavy downhill use, he always prefers 20mm. During his 2013 season though he was always on a 15mm axle setup and was fine, at no point did he wish for 20mm axles.

charger cartridge

Here it is possible to see a closed bath cartridge, with no air in the system.

Cartridge and Spring Options

The two main systems for springs are air and coil springs. Both have advantages, with air springs generally noted to change their spring curve as they heat up, but by their nature be lighter. Metal coil springs tend to be more sensitive to small bumps and retain their spring curve more in all conditions and extended usage, but are heavier and require removal and swapping out for adjusting sag.

Damper cartridges are generally of two main types, closed and open bath. The closed systems are lower maintenance and more user friendly, open bath systems are more after market adjustable and in some cases  work better, (our test), but this area of fork design is constantly evolving and right now it seems the new Charger cartridge from Rockshox is on a winning streak with performance, with all the top riders raving about it. Marzocchi with their open bath design though are still great forks. When comparing the two styles of cartridge back to back, they are pretty close in performance.

Fox Float 34 with a really nice feature, Kashima Coat.

Fox Talas 34 with a really nice feature, Kashima Coat.

Our Brand Recommendations

The main question then is which is the better fork for my riding style? Well straight off the top we will concede the new Pike from Rockshox is probably the best one out there at the moment from the point of view of weight, sensitivity, maintenance, reliability and price. In all wheel size options it works great and is race proven.

We have tried lots of the forks on the market, and the Pike is defiantly the one to beat at the moment.  Marzocchi though with their 55 are also contenders in our opinion, although they loose out because they have a greater maintenance schedule frequency. Fox with their float system are ubiquitous in the market, look good, have lots of really nice features and also have a lot of solid results behind them, however their performance curves and actual feeling on the bike compared to the Pike at the moment is not as impressive.

One brand though which we haven’t mentioned but have tried is BOS. A smaller company but with some incredible engineers behind the product, we would say are also a very valid option, from our short time on one of these we would recommend them, they are though slightly harder to get hold of and local maintenance in bike shops might be a problem, requiring the fork to be sent away.

This man is riding our favourite fork of 2013.

This man is riding our favourite fork of 2013.

Conclusion

The market for forks is constantly changing with new fashions and performance always changing. Up until the Pike’s release we were firm believers in the Marzocchi and Fox forks, however now Rockshox have upped the anti with their Charger cartridge and are probably on top. We are sure though the other companies have taken note and are currently developing products which will compete in this very technical part of the bike market. Whatever the choice though, good maintenance is key, forks need to be looked after, do that and they will perform well and make your ride more enjoyable, our recent experience with fork rebuilds only highlighted that.

Links for Fork Manufacturers

www.bosmtb.com

www.ridefox.com

www.marzocchi.com

www.sram.com/rockshox

www.xfushionshox.com

28 January 2014  ~  Written by

I-MTB is an online MTB magazine and trail areas operator based in Tuscany, Italy

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