Maintenance-free, durable bearing technology in heavy-load cargo bikes

It carries a payload of up to 350 kilos and is almost as light as a two-wheeled e-bike: the cargo bike from Fulpra is the ideal vehicle for the last mile of city logistics. Each component is designed for high loads and minimal maintenance requirements. For the sliding doors of the cargo space, the designers rely on drylin W profile rails, which, thanks to their dry operation, run maintenance-free and permanently smooth. Compact, lubrication-free and highly resilient igus bearings are also used in the drive train and parking brake.

Profile

What was needed: Profile guides for the sliding doors of the cargo space; alternative for metallic rolling bearings in the parking brake and in the drive train
Requirements: Smooth operation, wear resistance and durability, freedom from corrosion, resistance to dirt and temperature fluctuations, compact installation space, maintenance-free
Application area: Bicycle industry

Already in use successfully in the Netherlands, Norway, Sweden and tested in Cologne: the e-bike from Fulpra Motors BV rides comfortably like a two-wheeler in bends thanks to a special tilting system. At the same time, the cargo structure remains strong horizontally and allows payloads of up to 350 kilograms to be transported quickly through the city.

Problem

"The bike is designed from the ground up for heavy loads and heavy duty operations with minimal maintenance. This applies to every single component," says Michel van Eynatten, co-founder of Fulpra. He and his team therefore rely on bicycle components only for saddles and pedals, but otherwise use components from the motorcycle industry that are designed for heavier loads. For the suspension and guidance of the sliding doors of the cargo space, the designers were looking for profile guides that were as robust as they were smooth-running. "It is very important that the guides have a long service life under adverse conditions. After all, the doors are opened at every stop." Changing weather conditions, vibrations and shocks while driving must not impair the function.
The parking brake also required very strong and highly durable bearing components. This is because the brake must be able to safely hold the fully loaded cargo bike with a total weight of 600 kilograms on an incline of 20 percent.

Solution

Joint engineering with the Dutch igus representative Elcee produced the best technical solution for the sliding doors: drylin WSQ profile guides. The 1.40-metre long guides made of hard-anodised aluminium can be easily integrated into the structure of the cargo space. The special feature of the drylin linear system: the housings are equipped with iglidur J plain bearing liners, which ensure low-friction, smooth operation, completely without lubrication. This eliminates the need for regular maintenance and the problem of greased bearings attracting dirt and wearing out more quickly. The linear bearings do not rust, rattle or block and move perfectly well even in wet conditions, frequent use, shocks and vibrations.
For the bearing points in the parking brake and in the chain tensioners, igus offered the best solution: iglidur flange bushings of the X-series. They are characterised by a very high compressive strength and, like all igus bearings, do not require any additional lubrication thanks to their incorporated solid lubricant. Furthermore, they are much lighter and more compact compared to metallic rolling bearings.