Zero Friction Cycling showed X01 Eagle chain durability is off the charts compared to other stuff. The mileage I described above was achieved by swapping chains at 0,5 %, though Eagle chains come "pre stretched" to 0,25 % anyway (I'm guessing there's some more clearance in the rollers that the measuring tool incorrectly measures as wear due to the way the measurement is made). Considering I'm on the original aluminium front ring and considering the cassette has two teeth missing on the 50t, this is the last chain on it and it's a to the death situation. As long as...