Did you notice it, late last month, when the design of motorcycles made a fundamental shift into the future? Probably not. It was just a press release from BMW, announcing another small development for its bikes. Except it’s really not that small at all.
It’s the creation of the “M Endurance” maintenance-free drive chain. It never needs lubrication and it doesn’t stretch, ever. You can read the techie details here, but it boils down to BMW developing a massively hard coating for the chain rollers, which protects the seals for the lubricant. This coating is just below a diamond in its hardness, which means it doesn’t wear off. Think of it as the Vinnie Jones or Chuck Norris of drive chains.
Of course, this won’t affect motorcycles that are driven by solid shafts (which is, ironically, probably the majority of BMWs) or drive belts (which is most Harley-Davidsons). But most motorcycles around the world are driven by chains. They are much lighter, less complicated, and less expensive than the alternatives, but they need constant lubrication and adjustment.
The weak point of any chain has always been the roller bearings, which allow the individual links to slide around the sprockets. Chain links themselves don’t actually stretch – it’s the bearings that wear down and allow extra movement, which ultimately makes the chain a little longer and in need of adjustment to keep it tight and effective.
Originally, chains with standard bush bearings needed to be oiled every few hundred kilometres, and the sticky chain oil itself made sure road dirt and dust would get stuck to the outside of the chain. One short ride through sand and all the grit would be sealed into the links, making the situation worse and another cleaning essential. Desert riders would usually just run their chains as dry as possible to extend their short lives.
Many vintage motorcycles, and even many of today’s cheap commuters and step-throughs that use chains, have enclosed chains, contained inside a case. The cases don’t look that good though, so they’re not popular on classic bikes. They can also be fiddly for adjustment.
Then in the early 1970s, somebody invented O-ring chains, which use little rubber rings around the bearings to seal in the lubricant and keep out the dirt. This dramatically increased the life and strength of the chain. It also increased the cost, but the extra outlay was offset by the reduced need for replacement. These days, most motorcycle drive chains are O-ring chains.
Somewhere along the way in the last half-century, somebody else invented X-ring chains, which are more focused, more precise, in the way their rubber seals keep in the lubricant and keep out the dirt. They cost a little more but again, they last even longer – as much as twice as long in some circumstances, apparently. More to the point, they reduce friction still further and so they’ve become standard on high-performance bikes.
Now, BMW has moved on by coating X-ring chains with its new “tetrahedrally amorphous carbon” or “ta-C” material, which it also calls “industrial diamond” for regular people like you and me to understand. It claims this will offer “maintenance comfort equivalent to that of a shaft drive motorcycle. This includes all the cleaning work that is unavoidable with a conventional chain due to splashed lubricant. Accordingly, the M Endurance chain also offers maximum environmental friendliness.”
At the moment, the new chain is only available in a 525-pitch size, and just as an option for the S1000 RR and S1000 XR, though it will soon be sold in other sizes and for other bikes. Naturally, it costs more: the standard X-ring chain for these bikes sells for $265, while the M Endurance chain sells for $500. There’s no mention of whether the sprockets will last any longer.
This all brings us a step closer to a maintenance-free motorcycle. Modern bikes don’t need their tappets and points adjusted, or their carburetor needles cleaned. They no longer blow overheated light bulbs, and we don’t have to remember to shut off the fuel when we park. Tire tubes don’t need to be patched. Some bikes don’t even need keys in the ignition, and their suspension can be perfected with the press of a handlebar button.
There’s still plenty inside an engine and transmission that can blow up and keep motorcycle mechanics – sorry, technicians – busy for years to come. However, I doubt many riders will miss the tedium and mess of lubing and tightening a drive chain, especially out on the road on a long trip.
All the same, I’m glad I still have my old Suzuki, with her carburetor and kick starter. She’s there to remind me just how far we’ve come. Now if only I can get her running again…