Schwalbe estimates that the Marathon Supreme will last 5-9 000 kms. Not clear if they refer to the front or rear tire. If they mean average, then a conservative estimate might be that a rear tire will last 3 000 kms while a front will last 9 000 kms. Rotating at 2 000 kms would result in an expected minimum life of close to 4 500 kms (4,3k for the rear and 5k for the front), which would be enough in our case.

(We'll be carrying one spare and should be able to find more under way if needed.)