FINAL REPORT, 26 April 2015
The test was aborted at 3562km on 26 April 2015 when the Bafang QSWXK front motor on my bike gave up the ghost and was replaced by a Bafang BBS01 mid-motor (on which the 38T Surly chainring couldn't be made to fit), the new motor in a new test receiving its own brand new KMCX8 chain.
Just a reminder. The purpose of the test was to run a KMC X8 chain 4506km on the factory lube, inside a Hebie Chainglider, with a Surly stainless steel chainring and the normal Rohloff sprocket at the rear. The 4506km was set as a target by the previous chain, also KMC X8, running in a Utopia Country chaincase (similar to the Chainglider), but with Oil of Rohloff added every 500 or 1000km, reaching 4506km before visible "stretch" was found (less than 0.5mm). The ulterior, overall motive of the test was not to save a few Euro on chains but as a step towards a near-zero maintenance bike.
A gilmpse inside the famous Jute Laboratories.
That's the 0.75mm side of the gauge, so the chain wear, eyeballed, could be around 0.5mm
The KMC X8 chain ran on the factory lube inside the Hebie Chainglider together with a Surly 38T stainless steel chainring and a 16T Rohloff OEM sprocket, without any other lube being added at any time, or any cleaning being performed, for 3562km before the test was aborted, as described above. During this time the wear on the chain, measured as "stretch", was less than 0.75mm, eyeballed on the rough gauge as around 0.5mm. There is no doubt in my mind that the KMC X8 would have made 4506km by the time it required replacement at 0.75mm "stretch".
However, I'm happy to replace chains, the cheapest component in my transmission, at the first sign of measureable wear, which is around 0.5mm, so in that sense the factory lube fell short of the same chain under roughly the same circumstances serviced with Oil of Rohloff, 3562km to 4506km.
No excessive wear of the Surly stainless steel chainring or the Rohloff sprocket was observed. In fact, there is no wear observable. (This is very unlike my previous installations of Shimano Nexus transmissions, in which in around a 1000m/1600km I would use up a chain, a sprocket and a crankset because the chainring was in unit with the crank.)
The late, great Sheldon Brown once said that the factory lube was good for 700 miles. In my two experiments the factory lube plus Oil of Rohloff chain went 944km further than the factory-lube only chain. That, if scaled up to the full 0.75mm wear, is pretty close to Sheldon's 700 miles!
Now, I know, some of you think that 3500km and 4500km on a chain isn't much chop, the mileage of a wrecker. But I'm over the moon with these mileages. Considering that previously I rarely got over a thousand miles (1600km) out of a chain, two and three times that distance per chain is exceptional.
I'm very happy to declare these two experiments, 8068km altogether, a success.
They have confirmed my belief that the only enclosed chaincase that I can in good conscience recommend is the Hebie Chainglider, that KMC makes high commendable chains, and that Oil of Rohloff is the light chain oil of choice. I suspect that another thing they indicate is that a precision chainline is worth setting up with repayment for the effort in extra chain mileage.
With thanks to all who helped with advice, and to everyone for their patience in waiting for these results.
This is Andre Jute signing off with only slightly oily hands.
