Best suspension on the saddle with maintenance-free iglidur flanged bearings

• What was needed? Plain bearing for four bearing points at the pivot points of the parallelogram seatpost
• Requirements: wear resistance, low coefficient of friction, lubrication/maintenance-free, insensitive to edge pressure
• Area of application: Bicycle industry, bicycle components

The by.schulz GmbH develops high-quality bicycle components, which are used in the original equipment of premium bicycle manufacturers, but are also available as accessories in the trade. A product highlight: the suspended parallelogram seat post G.2. It has been tested with two suspension travel lengths (30 and 50mm) for different rider weights up to 150 kilogrammes and a bicycle magazine simply judged: "Super".

A high quality of the components was important to the designers. Gerd Brücker, design engineer at by.schulz: "The aluminium tube is 3D forged with different wall thicknesses - this saves weight. The flat wire spring is located directly in the force flow and is 50 per cent compressible. It takes the load well and responds faster than round wire springs." Elastomer elements serve as end cap. The material selection for the four bearing points at the pivot points of the support, whose spring is virtually clamped in a parallelogram, was also a matter of finding the best solution in terms of quality. The challenge: "The axle makes oscillating movements when it is spring loaded. In the process, the bearings are subjected to high stresses in a small section," says Brücker. In the first series brass bushings and stainless steel axles were used. This meant that the bearings had to be lubricated regularly, and the manufacturers wanted to avoid this in the further development of the prop. That's when igus bearings made of high-performance polymer with incorporated lubricant came into view - and initially faced reservations. "At first, we didn't believe that plastic bearings would meet our high requirements," says founder Markus Schulz. But the developers - always open to new ideas - were willing to try. This included both driving tests by.schulz with converted seat posts and special test series in the igus laboratory.

The collar bearings made from the material iglidur W360 reached the calculated long service life and also offer other advantages. Gerd Brücker: "The coefficient of friction is low and thus also the breakaway torque. That means the suspension is more responsive, there's no jerking." The very good and reproducible dimensional accuracy of the injection-moulded bearing also means that CNC machining of the adjacent metal components can be carried out very precisely: As there is no lateral clearance Tighter tolerances possible during processing. Another advantage: plastic bearings forgive edge pressure rather than brass bearings: Since the clearance only sets in when the bearings are pressed in, they adapt better to the surrounding construction. This also helps to ensure that the suspension always responds optimally. And finally: the bearings are Light and need No additional lubrication.

Markus Schulz points out that the question of "brass or plastic?" was not primarily a matter of cost: "For us, it's always about optimum function." However, the appearance also plays a role, which is why igus manufactures the bearings for by.schulz in a special black colour.