The gear chain is a wearable component and therefore the lifespan cannot be measured in ridden kilometers. Due to the applicated use, the shifting method of the rider and the condition of the chain itself, the lifespan of the gear chain can vary enormously. Naturally the starting quality of the chain plays a very important role.
In high performance use, the bicycle chain receives up to 500kg of force. Therefore, an extremely high level of surface pressure of 300kg/mm2 is to be found here within the chain links. The smaller the chainrings are up front, the greater the amount of force is which is applied to the chain and with it, the amount of surface pressure applied to each individual chain link (e.g. all MTBs running compact drive, microdrive, and hyperdrive C). The amount of surface pressure also increases when the chain is running at an angle because the contact area is proportionately reduced.
Even though the Rohloff chain with its optimal patented linkage system greatly reduces the amount of wear caused by this surface pressure, it still needs to be lubricated the same as any other type of bicycle chain. Without this lubricating film between the contact surfaces, an abrasive friction will occur accelerating the level of chain.
One of the essential wear factors is the amount of dirt which has penetrated the chain linkages. Hard particles (e.g. sand) could enter the chain and lie on the above surface of the bearing collar, this sand then starts to work identically to sandpaper. Material from the pin surface will slowly be worn away, a little lubrication helps even if this occurs. To fully understand this effect, we will turn back to the sandpaper example: Dry sandpaper is very abrasive. When however, it is used with a lubricant (e.g. water), the abrasive effect is conciderably reduced. With oil as a lubricant, the abrasiveness of the sandpaper has hardly any physical effect.
The manufacturers can increase the lifespan of the chain by designing an optimal linkage system, precise finishing and the use of an extremely hard pin surface.
The consumer themselves can considerably increase the lifespan of their chain simply through regular cleaning, lubricant reapplication and inspection of the components condition.