Flex series - Comfort for MTB: Vibration alarm - 5 parts against arm pump & tired hands in the test

Every biker is familiar with sore hands and arms. Fingers and forearms in particular tire quickly under the heavy loads on rough terrain. After a long descent, it is sometimes difficult to grip properly. The syndrome is called arm pump. If the continuous load is too high, the swollen muscles press against the surrounding fasciae. If the muscle does not have time to recover, this can lead to pain or numbness and, in the worst cases, even result in chronic muscle damage.

However, not only extreme downhill riders are affected, but also touring bikers. Constant vibrations on an MTB tour can lead to numb hands and premature arm fatigue. In a world where advancing mountain bike technology allows more and more people to ride longer and more extreme routes, arm pump has become a widespread disease. But if the marketing slogans of manufacturers of stems, handlebars and grips are anything to go by, premature fatigue and arm pump can be combated with the right hardware. We have tested five comfort products for sporty biking.

Stems, handlebars and grips for more comfort

We tested the following cockpit parts in the laboratory and in practice:

• Redshift Shockstop Pro stem
• Vecnum Freeqence stem
• One Up carbon handlebars
• Spank Spike 35 Vibrocore handlebars
• Revgrips Pro handles

In the fight against tiring vibrations and shocks, these parts each pursue very different strategies. Redshift and Vecnum rely on suspension stems. This approach is anything but new and experienced a brief heyday in the colourful 90s. The idea has now been revived with the spread of gravel bikes.

Unlike the Redshift Shockstop, the Vecnum Freequence stem is only approved for use with a rigid fork, which naturally limits its relevance for the mountain bike scene. Nevertheless, unsprung hardtails are still brilliant training tools and have a loyal following.

Both suspension stems are quite expensive at just under 300 euros and both rely on the damping effect of elastomers. While Redshift uses a single joint and one or two elastomers, Vecnum uses four joints and elastomers. This has a significant effect on the function of MTB handlebars. While the Vecnum responds very sensitively regardless of the shape of the handlebars, the Redshift's suspension is rather firm and its function is influenced by the handlebars. The spring stiffness can be adjusted in four stages on the dismantled Redshift. With Vecnum, continuous adjustment is possible on the trail.

The One Up carbon handlebars aims to provide the same comfort as a 31.8 mm standard handlebar despite the 35 mm clamp. Overall, the One Up handlebars impressed us with their excellent riding characteristics. Handling and damping are at a high level. However, it is only worth changing to the carbon handlebars, which cost just under 190 euros, if you absolutely have to have 35 mm handlebars and the previous handlebars were too stiff. Otherwise, the advantages over other cockpit setups are too small.

The situation is similar with the Spank Spike Vibrocore from. Spank claims to have manipulated its vibration behaviour with a foam core, which is said to give the handlebars a natural vibration in a higher frequency range and amplify vibrations less than other handlebars. In the test, we were able to attest to the good comfort and precise steering behaviour of the rather heavy Spike Vibrocore. Once again, the vibration-damping handlebars from Spank are a very good piece of kit, but we were only able to feel the advantages of the Vibrocore system to a limited extent in comparison with other handlebars.

The American company Revolution Suspension Grips, or Revgrips, has taken a unique approach in the fight against arm pump. Thanks to an elastomer suspension, the grips rotate around the handlebars to a small degree. This means that the hands work with the grips instead of against them, and therefore last longer. Our test revealed a clear comfort advantage, which is also due to the very good damping properties of the grip rubber itself. In addition to the high price of 99 euros for a wear part, problems with the durability of the grips tempered our euphoria.

Comfort parts: High prices, weak effects

Our test series clearly showed that the advantages of comfort products are difficult to generalise. Nevertheless, the topic is on every mountain biker's mind. So there is plenty of room for marketing slogans. In practice, the stems, handlebars and grips with the extra portion of comfort usually only revealed their raison d'être after many kilometres of testing.

We spent a total of eleven hours riding the five products. This included short laps, during which we switched back and forth between the parts and comparison products without promises of comfort, but also long rides. The latter in particular brought out the advantages of the parts. In the long term, they all have the potential to increase the comfort of the MTB cockpit. In some cases, however, the advantage is only small.

So it makes a huge difference which setup you come from and how sensitive your own body is to arm pump. If you set up your bike yourself, you can of course use flex products right from the start. In our opinion, switching often makes little sense due to the high prices.

How useful are Flex products for the cockpit really?

Comfort is always the result of a chain. Shocks and vibrations reach the rider via the system of tyres, wheel, fork, frame, stem, handlebars and grips. Analysing the comfort properties of a single component is therefore only partially meaningful.

For example, the many comparisons during our test showed that a certain level of comfort can be achieved with many different combinations of parts. There are countless stems, handlebars and grips on the market. They all have different stiffness values and damping properties. None of the parts we tested alone provide sufficient comfort if the rest of the bike is uncomfortable.

Fun fact: After the test week, our editor had aching wrists and forearms for several days. Even the best comfort products don't stand a chance against many kilometres of trail riding - sometimes on unsprung hardtails with rigid forks.

The damping properties of other components in particular call into question the importance of special comfort products for the cockpit. Tyre pressure, for example, plays a much more decisive rolethan a flexing handlebar will ever do. Off-road, switching to a tubeless setup with low air pressure can therefore be significantly more effective and cheaper than buying a special comfort product.

There is also a lot of potential with the grips. Soft models with damping slats can generate significantly more comfort than most bikers probably think. It only makes sense to buy flex parts for the cockpit once other parts of the bike have been optimised. Armpump is also heavily dependent on the general bike set-up. If the running gear is set incorrectly or the If the position of the brake levers is not optimaleven the best comfort products won't help.

To summarise, it can be said that all the tested parts fulfil their function, but do not have to be the first port of call in the fight against aching arms and hands when mountain biking. Training can also help to prevent premature fatigue of the hand and forearm muscles. There are also other Causes of painful hands when cycling.