The BIKE practical test in Bolzano
With a difference in altitude of 700 metres and an average gradient of 20 percent, our test route from Jenesien down to Bolzano is a real challenge for brakes. After the braking procedure recommended by the manufacturer, the first 300 metres of descent are downhill on a selective trail with hairpin bends, slippery and loose surfaces. The first part is used to assess modulation, lever ergonomics and hand force.
The stability and braking power of each brake is tested over the next 400 metres on asphalt. Each of the three testers (75, 85 and 95 kilos) rides a complete descent for each brake model and disc size. On the tarmac section, we only brake at the front to assess the stability and to ensure that each brake is subjected to the same load. For this purpose, each brake is loaded according to a defined mode (short grinding braking, interval braking, deceleration from 40 km/h). As you don't know beforehand how reliably a new brake model will work, we fitted a known brake at the rear as a rescue anchor in case the front brake fails.
The BIKE laboratory test for disc brakes
To confirm the results from the field, we also test all brakes on our in-house drum test bench. During the measurements, we record braking and manual forces (hysteresis curve) and the brake lining temperature. A fan ensures constant cooling.
Braking
For optimum deceleration, the brake pads and disc must first be able to adapt to each other. This involves at least 60 braking applications at a moderate rolling speed until the braking effect has reached a constant level. The temperature is monitored to ensure that the pads do not glaze over.
Hysteresis curve
The braking force and hysteresis curve for dry (red) and wet braking (blue) at room temperature are then determined. The curve in the test letters shows a brake with a 180 mm disc at a rolling speed of 45 km/h and a manual force limited to 120 N. The braking force assessed in the test letter is the result of averaged dry and wet braking at 80 N manual force and the test driver's assessment from the practical test.
Stability
The fading test on the roller is carried out in three increasing stages and is based on data obtained in practice. The results of the laboratory test together with the points from the practical test result in the assessment of the stability in the test letters. Based on the results of the practical test, we also indicate the rider weight up to which the brake can withstand extreme downhill gradients.
Test evaluation of the disc brakes
In addition to braking power, stability, ergonomics and modulation, the weight and ease of installation/adjustment of the brake are also included in the final score.
