Absolute silence. Everyone knows that tiny moment before impact when the world seems to stand still. And everyone knows: it's about to really hurt. When the fall can no longer be avoided, all you can do is hope that you hit the bush next to the rock, that you don't ram your arm into the ground on reflex, or that you are well equipped. A rucksack with a back protector certainly can't prevent grazes or bruises on the shin. But it can protect a vital organ: the central nervous system. Or rather a part of it, namely the spinal cord.
You can find these protector backpacks in the test:
- Aplifi Stratos MK II
- Bliss ARG Vertical LD
- Camelbak K.U.D.U. 12 (BIKE tip: test winner)
- Cube Freeride 20+
- Deuter Attack 20
- Ergon BA3 Evo Enduro Protect
- Evoc FR Trail
- Poc VPD 2.0 Spine Pack 25
- Scott Grafter Protect 12
To test how well the current generation of protector backpacks shield our motorised distribution centre, we took nine models to the TÜV Rheinland test laboratory. Not only are the standardised tests carried out there, but many commercially available products are also certified. Manufacturers must prove that the back protectors really do protect by displaying the CE test seal clearly on the product. Without it, the protective equipment is no more allowed on the market than a pair of dungarees in Munich's posh P1 disco.
Incidentally, there is no special test standard for off-road sports. This is why all back protectors are tested according to the current motorbike standard EN 1621-2. We based our test on this standard. However, instead of a flat impact element, a wedge-shaped metal body weighing five kilos falls onto the backpacks from a height of one metre. This makes the conditions in the terrain more realistic. On the one hand, you rarely fall onto flat tarmac on a mountain bike, but in the worst case onto an angular rock. Secondly, the protector plates alone cannot be used without a rucksack. With the exception of Evoc: on the FR Trail, the protector element can be zipped off and worn separately. Christiane Reckter from the product testing department can recognise a good protector by its sound. As soon as she presses the green button on the test stand, the metal body is subjected to the force of gravity and crashes against the measuring unit with up to 180 kilonewtons. If it hits the test backpack quietly and muffled, this means that everything is fine. A hard, metallic bang, on the other hand, rarely bodes well. As a rule, you can then expect severe bruising, in the worst case bones splinter. Even the layman can hear that the protectors tested are a long way from the real thing. The test head crashes into the test specimens almost gently, as if into a pile of feather pillows.
The protector backpacks in the impact test
The Camelbak K.U.D.U. achieved the best value in the test with an average residual force of 5830 newtons. A total of six products are below the 9000 Newton limit and therefore fulfil the better level 2 of the CE test EN 1621-2. Amplifi, Cube and Bliss "only" achieve level 1, which reaches an average residual force of 18000 Newtons. However, even the worst measured value of 13743 newtons is still well within the maximum acceptable value of 24000 newtons.
Even the "worst" back protector dissipates 92 per cent of the impact energy. This means that Amplifi, Bliss and Cube still easily fulfil level 1 of the test standard. In the case of the Camelbak, only 5.8 of the original 180 kilonewtons penetrated through to the measuring sensors, i.e. to the wearer, so to speak. For level 2, the measurement diagram should show a maximum of 9 kilonewtons. The values are all the more surprising when you consider that the protectors are only about as thick as a bar of chocolate.
However, the EPS plates from Ergon and Evoc have done their job after a crash. Just as you only have one go at a car airbag, the disposable protector also has to be replaced after a crash. The plastic is crushed or breaks. The foam protectors from other manufacturers, on the other hand, work in a similar way to a tennis ball: when hit, their microscopic bubbles deform and then return to their original shape. Theoretically, you could therefore fall on the protector many times. "However, it is never 100 per cent certain whether an impact has damaged the structure of the foam," explains Christiane Reckter. In any case, she advises having the protector plate checked by the dealer or manufacturer after a fall and replacing it if necessary.
It's certainly safer than relying on the next fall to land gently in the bush and not hit the rock next to it.
Knowhow: Soft protectors
The advantages of soft protectors are obvious: they are light and flexible and therefore perfect for sports use. There are basically two different designs. However, the term "multi-impact" should be used with caution.
EPS protector
Evoc and Ergon use so-called disposable protectors. Their core is made of expanded polystyrene (EPS), the same material used in helmets. In the event of an impact, the EPS deforms permanently and must therefore be replaced. Care should be taken during transport. If the plate is bent too much, the material can break and lose its protective effect.
Foam protector
Camelbak, Deuter, POC and Scott rely on polyurethane foam. This consists of countless air-filled bubbles that deform on impact and then return to their original shape. Even if the manufacturers approve the products for multiple impacts, the structure can be damaged by a hard impact. Foam protectors should therefore also be thoroughly inspected after hard impacts and replaced if necessary.
Armourgel protector
Armourgel, as used by Amplifi, Bliss and Cube, is a special case. The material is not foam, but a silicone fluid that is moulded into a special S-cell shape. In the event of a fall, the impact energy is dissipated sideways by shear forces, thus decelerating the impact. The main advantage of Armourgel is its temperature stability: the protector works just as well in extreme heat as it does at -20°C and always remains flexible. The material also contains no air. This means that Armourgel cannot soak up moisture and can even be washed at 30°.
Things to know about MTB backpacks
What is allowed and what should you stay away from? We have simulated other situations in addition to the rucksack tests and show where problems can occur.
How BIKE tests protector backpacks
Laboratory test
In the TÜV Rheinland test laboratory in Cologne, we subjected all protector backpacks to a comparative measurement based on the currently valid standard for back protectors EN 1621-2 2014. In order to certify a protector, the protector's ability to absorb mechanical energy must be determined by means of an impact test. A stamp with the impact edge in the form of a kerb with a mass of five kilos is dropped onto the protector from a height of one metre. The protector lies on a slightly curved anvil with a force measuring device. The residual force under the protector is then measured. This residual force acts on the back and ultimately leads to injuries. The lower this value is, the better the protector absorbs the force. For the five required impacts, no residual force may exceed 24 kilonewtons (kN), while the average value must be below 18 kN (level 1). Impacts without a protector (steel drop body on anvil) generate a peak force of around 150 to 180 kN unbraked. In a second quality level, this requirement is raised to 12 kN as the maximum value and 9 kN as the average value (Level 2). As the back protector and rucksack are always used as a system (exception: the Evoc's back plate can also be used without a packsack) and the overall construction plays a major role in impact absorption, we did not test the protector plates separately. We also limited ourselves to three instead of five impacts.
Practical test
The carrying comfort and handling of the rucksacks were tested by the test riders with a standardised load of six kilos. The contents corresponded to complete touring equipment including a full two-litre hydration bladder.
How to read the results in the graphs:
Stefan Frey
Editor
