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BMW Motorrad announces “maintenance-free” motorcycle chain

In late August 2020, BMW Motorrad announced the M Endurance chain, claiming it to be a maintenance-free option to traditional motorcycle drive chains.

According to their press release, the M Endurance chain has a “resident permanent lubricant” for the rollers and pins enclosed by X-rings, like any other X-ring chain already being manufactured. Where it diverges from existing offerings is a new coating on the rollers, which they call tetrahedrally amorphous carbon (ta-C), a type of industrial diamond and state, “This coating is characterized by extreme hardness and resistance and in this respect it is placed between the well-known DLC coating (diamond-like carbon) and pure diamond.” BMW further states the ta-C coating drastically reduces friction and does not wear off over the lifetime of the chain.

Because of these characteristics, BMW says the chain never needs any additional lubrication, and thus eliminates the tedious cleaning associated with dirt attracted to chain lube or fling-off from over-lubricating the chain. A nickel-brass coating on the links should serve to inhibit rust.

DLC is not actually diamonds, but an amorphous carbon material which behaves like diamond in many respects. Ta-C is the hardest and strongest and has the least friction coefficient of known DLC substances, making it especially well-suited for motor vehicle applications. It is also the purest DLC, made up completely of sp3 bonded carbon atoms. Sp3 hybridization involving carbon atoms creates a molecule—in this case with a tetrahedral structure in which several carbon atoms bond with a central carbon atom at an angle of approximately 109 degrees—with minimal repulsion among their electrons. The presence of only carbon atoms in ta-C instead of fillers such as hydrogen as used in other DLCs gives the ta-C molecule its superior characteristics for strength, hardness and friction. Ta-C is effective in a coating as thin as two micrometers.

BMW says the M Endurance chain will be initially available only in 525 pitch for the S 1000 RR and XR motorcycles as an accessory or directly from the factory.

The S 1000 R and RR models equipped with standard wheels have the same wheelbase (56.7″) and come stock with 17-tooth countershaft sprockets, 45-tooth rear sprockets and 120-link chains; even though BMW doesn’t state the new chain is available for the R, it will fit. The XR’s sprockets are the same as the other S bikes, but the chain is longer, running to 128 links due to its increased wheelbase (59.9″).

Because the M Endurance chain for the S 1000 XR is long enough, it may be suitable for the F 900 R (wheelbase 59.7″) and possibly even the F 900 XR (wheelbase 60″). Even though the wheelbase on the F 850 GS/GSA (62.7″) is much longer than the S 1000 XR, its specifications call for a 122-link chain, so it wouldn’t be unreasonable to cut down the 128-link chain to fit the 850s and 900s. Because the G 310 models use a 520-pitch chain, an owner with one of those would have to switch their bike to 525-pitch sprockets to take advantage of the new chain, which may or may not be possible depending on the engine housing around the countershaft sprocket. (When in doubt, check with a BMW-certified technician before making changes of this sort to your motorcycle.)

Riders skeptical about “lifetime” or “maintenance-free” claims related to motorcycle final drive components will, of course, take the news of this new chain with a grain of salt, but the idea of a chain you never have to adjust will no doubt appeal to many riders, even those without BMWs under them. Not having to spray cleaners and lubricants on a chain means a smaller environmental footprint, something BMW touches on in their press release as well.

Motorcycle (2019-20 MY) Wheelbase Front Sprocket Rear Sprocket Chain Pitch Chain Length
S 1000 R/RR 56.7″ 17 45 525 120
S 1000 XR 59.9″ 17 45 525 128
F 850 GS/GSA 62.7″ 17 44 525 122
F 900 R 59.7″ 17 44 525* 122
F 900 XR 60″ 17 44 525* 128*
G 310 GS/R 54″ 16 40 520 112

* Unable to confirm, but reasonably likely given available technical data.

 BMW Motorrad has not announced pricing for the M Endurance chain nor a date it will be available.

Thanks to Stuart Beatson at Morton’s BMW for providing some technical data for this article.