The knee consists almost entirely of skin and bone. Falls here are particularly painful. Knee protectors reduced the forces occurring in our test by up to 96 per cent.
The inner workings of knee protectors
- The thickness of the protector is decisive for the cushioning behaviour of the protector. The material of the POC VPD 2.0 is one of the thickest in the test. As a result, it absorbs an enormous amount of impact energy. However, as the material is relatively firm and tough, mobility suffers when pedalling.
- The shape of the protector plays a subordinate role in the TÜV test. In practice, the protective cap should also cover the side of the knee joint, as is the case with the Scott, for example, and extend quite a way down over the kneecap. This ensures that no sharp objects can penetrate the joint in the event of a fall.
- The right material makes the difference in the event of a fall. A foam protector distributes the forces over a larger area. Hard shells transfer the forces much more directly to the knee and generally only work well if there is good foam cushioning behind them. What happens if this is not the case can be seen from the impact values of the YT protector.
Test according to TÜV standard for motorbikes
We wanted to know how well current knee protectors really protect. As we were unable to find a colleague to carry out a live test, we sent twelve soft and hard-shell protectors to TÜV Rheinland. The damping behaviour of the individual protectors was tested there on the basis of the current motorbike standard EN 1621-1. There is no specific standard for cycling. However, Christiane Reckter from the product testing department explains that since mountain biking sometimes reaches similar speeds to motorbike riding, the test procedure is very practical. Soft protectors usually come out on top in the test, as they distribute the forces better over the surface.
The lower the residual force, the better for the knee. A total of six manufacturers fulfil the better EN protection level 2. Two manufacturers did not pass the TÜV Rheinland test.
These protectors are being tested:
- Dainese Oak Pro
- Dainese Trail Skins
- ION K_Pact (BIKE-TIP price/performance)
- IXS Dagger
- Leatt 3DF
- O'Neal AMX Zipper
- POC VPD 2.0
- Scott Grenade II Pro
- Seven Protection Control Knee
- SixSixOne Rage
- Sweet Protection Bearsuit (BIKE-TIP protection)
- YT Industries Shit Bumper
This is how we tested at TÜV Rheinland:
Laboratory test In the TÜV Rheinland test laboratory in Cologne, we subjected all knee protectors to a comparative measurement based on the currently valid standard for joint protectors EN 1621-1 2012. 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 hemispherical anvil with a force measuring device. The residual force under the protector is then measured. This residual force acts on the knee joint and ultimately leads to injuries. The lower this value is, the better the protector absorbs the impact. Impacts without a protector (steel impactor on anvil) generate a peak force of around 150 to 180 kN without braking. The standard test requires five impacts to certify a protector. Of these, no residual force may exceed 50 kilonewtons (kN), while the average value must be below 35 kN (protection level 1). In a second quality level, this requirement is raised to 30 kN as the maximum value and 20 kN as the average value (level 2). In our test, we limited ourselves to three instead of five impacts.
Practical test The fit, secure fit, possible pressure points and ventilation properties of the knee protectors were determined by various testers in practice. Handling is also included in the assessment, for example whether the protector plate can be removed for washing and how easy the protectors are to put on and take off.
You can read this article from BIKE 4/2015 in the BIKE app (iTunes and Google Play) or buy the issue in the DK shop reorder:
Stefan Frey
Editor
