Wheels on roller coasters are a limiting factor for their operational capability. Roller coasters reach their limits in some countries in the summer and at worst cannot be operated with a full number of passengers. This is due to the rise in temperature caused by climate change or exposed coasters in desert areas. In the construction of new coasters, more complex or equipped vehicles with more safety features lead to an increase in weight, which also pushes the wheels to the limits under normal conditions.

Engineers need to find the best combination for their system for roller coaster from these four main requirements:

1. Low rolling resistance:

 On a roller coaster, friction losses must be minimized so that the train can easily pass its route, consisting of complex and dynamic maneuvers. Furthermore, the rolling resistance in the range of -5 to +35°C outside temperature should be as equal as possible, so that the speed on the track varies as little as possible depending on the temperature. Wheel coverings with too high rolling resistance lead to loss of speed on the track and unnecessary heat build-up.

 2. High dynamic load-bearing capacity:

 Vehicles on roller coasters plunge down steep descents, accelerating to speeds of up to 140km/h and reaching vertical forces of up to 4.5g in the valleys at short notice. The wheels not only carry the weight of the passengers and the vehicles, but also have to accommodate the additional centrifugal force up to four and a half times. The combination of speed and load is a particular challenge for the wheel coverings. Lack of dynamic load-bearing capacity leads to increased heat build-up in the wheel covering, which in the worst case leads to a blow-out and total failure of the wheel.

 3. High driving comfort:

 From the passenger’s point of view, the most important prerequisite is to manage the route as shock-free and jerk-free as possible. The wheels must absorb shocks and defects on the track without being damaged. Rough rides are not only unpleasant for park guests riding on the roller coaster, they can also cause damage to the vehicle. The need to provide a smooth ride is directly at odds with the first two requirements, which could be solved by higher wheel covering hardness.

 4. Long shelf life:

 From the park operator’s point of view, the most important prerequisite is not only safety but also the longevity of the wheel coverings. Since a large number of wheels are installed on the vehicles, the inspection and maintenance costs are significant. Confidence in safe wheels and maintenance in the sense of normal wear and tear is a significant advantage for the park operator.

 At Asma, we are intensively engaged in optimizing polyurethane wheel coverings for roller coasters in terms of increasing customer demands. We can draw on extensive knowledge of polyurethane materials, testing possibilities and experience in applications, including Hyperloop. We offer the materials, testing possibilities and experience in applications, including Hyperloop. We offer the optimization of wheels with our polyurethane materials and our knowledge to OEM manufacturers as well as park operators. In addition to the polyurethane materials that a proved for many years, we have two new polyurethane materials (Asmaprene VP424, Asmaprene VP425) in our portfolio since 2020, which offer around 20% reserve in load capacity and speed, compared to our competitors high-speed wheel coverings. These wheel coverings are available in 94 and 96 Shore A.

 A proven tip: The speed of the roller coaster can be affected by mixing and adjusting wheels, which parks do to keep the ride running within the specified window.