A roller chain should always be well lubricated where friction occurs as a result of chain movement. This is on the link plates, between the chain pins and sleeves, as well as between the chain sleeves and the roller.
This is exactly where the oil gets to relubricate the grease pads with chain lubrication sprockets.
How it Works: See on example of lubricating pinions for a simplex chain
A plastic pinion made of highly wear-resistant plastic runs freely with the chain.
Two open-pore PU foam rings firmly attached to the plastic pinion are thus moved without slippage and at a precisely defined distance from the chain so that only contact between the chain link and PU foam takes place in the area of ​​the chain links.
This contact and the minimal contraction of the PU foam rings allows the lubricating oil supplied through the hollow axle to reach between the link plates exactly where it is needed.

This means that a drive chain or timing chain can be lubricated and maintained most effectively with the least amount of lubricant, without polluting the environment with excess chain oil, which would not be possible with lubricating brushes.
The avoidance of any friction between PU foam cylinder and chain, as well as the always equal, minimal contraction of the high-quality PU material guarantee a maximum service life of this chain lubrication solution.