Flex series - Comfort for MTB: Spank Spike Vibrocore: Handlebars against arm pump in the test

Long descents on an MTB are a bit like a rodeo ride, no matter how efficient and sensitive the bike's suspension is: The rider's body still has to absorb countless impacts. Especially on fast and rough trails, there is a lot of rumbling and the rider would do well to hold on to the handlebars. The more shocks are transferred from the handlebars to the body, the more tired the muscles become and the more likely it is that your hands will ache or go numb. "Arm pump", as the phenomenon has been christened, is the biggest enemy of demanding enduro and downhill riders. Ultimately, the vibrations on the handlebars are nothing more than oscillations and these can be explained by physics. The developers at component manufacturer Spank must have paid close attention in physics class and designed a handlebar that should vibrate less than others. We wanted to find out the science behind this and whether it can really be felt in practice.

How the Spank Spike Vibrocore handlebars combat arm pump

Bikers often accept arm pump as an unpleasant side effect of their sport. However, it becomes dangerous when the arm pain becomes chronic. Chronic Exertional Compartment Syndrome (CECS) is particularly well known in the motocross sector. However, CECS can theoretically occur anywhere where the body is exposed to low-frequency vibrations for long periods of time, including mountain biking. The permanent stress can cause the muscles in the forearm to swell and increase in volume by up to 20 per cent when pumped up with blood. Bikers know this phenomenon as "fat arms" after a long day in the bike park, for example. If the swelling becomes too severe, the muscle fibres press against the fascia in which they run. This leads to pain, reduced performance and, in the worst case, CECS.

To find out which vibrations lead to arm pump, Spank measured the frequency range in which MTB handlebars usually vibrate. The unevenness of the ground is transmitted to the handlebars via the tyres, wheel, front axle, fork, frame and finally the stem. As a rule, handlebars in MTB use vibrate at a frequency of between two and 200 Hz. Most vibrations are between five and 50 Hz. Unfortunately, this is almost congruent with the frequency range of eight to 50 Hz, which doctors consider to be problematic in terms of arm pump.

Fortunately, all handlebars dampen some of the vibrations, depending on their design and material. Nevertheless, all models have a certain frequency range in which they resonate with the rest of the vibrations. In this resonance range, which is normally somewhere between 12 and 25 Hz, the natural vibration of the handlebars actually amplifies the arm pump effect. This is where the greatest risk of sore hands and tired arms lies.

In order to avoid the amplification of tiring vibrations through resonance, Spank looked for a way to shift the resonance range of the Spike handlebars upwards. This is where the patented Vibrocore technology comes into play, which is designed to ensure that handlebar vibrations only occur in a higher frequency range. Although Spank does not communicate exactly which range this is, the higher frequencies at which the Spike Vibrocore handlebars begin to vibrate should occur much less frequently on the trail.

In order to manipulate the vibration range of the Spark Vibrocore handlebars, Spank does not rely on differently dimensioned carbon, but on an interior made of biodegradable foam. Like other aluminium handlebars, the Spark is initially hollow. With the help of "Dual Extreme Gradual Taper Technology", the tube that later forms the handlebars is drawn. This tapers from the clamping area and becomes thicker again at the end of the handlebar. 3D CNC bending machines then shape the handlebars. This is done fully automatically and is intended to maximise material utilisation and eliminate the need for structurally weakening grinding processes. The clamping area of the Spank Spike is then additionally hardened. Finally, the Vibrocore foam core is injected into the inside of the handlebar, which is supposed to have a vibration-damping effect. So much for the theory, but how do the Spank Spike Vibrocore handlebars perform in practice?

Details about the Spank Spike Vibrocore

• Price: 125,00 Euro >> e.g. available here at a reduced price
• Weight: 322 g (unabridged, BIKE measurement)
• Material: Aluminium
• Clamping diameter: 35 mm
• Width: 820 mm
• Can be shortened: yes, up to 760 mm
• Rise: 25 (tested) / 40 / 60 mm
• Geometry: 8 ° backsweep / 5 ° upsweep
• Special features: Foam core for vibration damping

How to ride the Spank Spike Vibrocore handlebars with vibration damping

This isn't the first time we've put the Spank Spike Vibrocore handlebars to the test. In fact, we already made a considerable effort for its premiere in 2016to quantify its effect. Back then, we even went out on the trail with complex measurement technology to determine the vibration damping of the handlebars.

The sobering result at the time: although an effect was measurable, it was in such a small range that it seemed to be meaningless in real biker life. We were unable to determine the advantage of the Vibrocore technology either in the laboratory or in practice. And today? The sixth generation of Vibrocore handlebars is now on the market, and our current test model comes with a large 35-millimetre clamping dimension.

The first impression of the Spank Spike Vibrocore handlebars: Massive part! With a width of 820 millimetres and a thick clamping standard, the Spike is quite a lot of handlebar. This is not only noticeable on the scales. Enduro riders can shoot downhill with a lot of confidence on the Spank handlebars. The steering precision of the large aluminium bar is at a high level. Nevertheless, the Spike feels quite comfortable for such a massive handlebar. What's more, among the 35 mm aluminium handlebars, it is one of the most comfortable to ride even after a long day on the bike. Hands and arms remain relaxed for a relatively long time. A sign of the miraculous power of Vibrocore?

Maybe. Once again, we can't confirm the power-saving effect of the Spank Spike Vibrocore handlebars with absolute certainty. In the laboratory, we were able to confirm that it has a greater deflection than other aluminium handlebars with a 35 mm standard. And with 27.56 N/mm measured by us, the stiffness of the Spank Spike Vibrocore is lower than, for example, that of a Race Face Atlas with the same dimensions or the OneUp carbon handlebar, which was also tested.

In practice, we noticed a certain comfort effect, but no superiority over other handlebars. No matter how many descents we pumped our arms and how often we switched back and forth with other handlebars: The big wow effect failed to materialise. Instead, it can be said that the Spike Vibrocore is a top handlebar for radical descents, but its comfort effect seems to get lost in the chain of effects. In terms of damping, the tyres and grips simply have more potential for optimisation than the Spank handlebars can offer. However, if you're looking for a bombproof but not too stiff aluminium handlebar with a 35 mm clamp, the Spank Spike is the perfect choice for downhill freaks.

Conclusion on the Spank Spike Vibrocore in the test - aluminium handlebars with foam core for more comfort

Unfortunately, we could not clearly feel the Vibrocore effect this time either. In comparison, there are simply handlebars without a foam core on the market that offer similar comfort - many of them with a lower weight. However, in the niche of downhill-compatible aluminium handlebars with a 35 mm clamp, the Spank Spike Vibrocore is a strong handlebar with a good feeling of comfort. - Jan Timmermann, BIKE editor

Pro

• Solid aluminium construction creates confidence
• Good ride comfort for material and clamping width

Contra

• heavy
• Benefit of Vibrocore technology low compared to competitor products and other components on the bike