a guy in the tuning department at Rover once told me that you get the best mpg by operating at the revs that would give peak torque on full throttle. so, gearing to run at lower rpm means less efficiency from slower turning engine and, hence, potentially worse mpg. ie I don't agree with gearing up for lower fuel burn and I agree it can put more load and hence wear on the chain. my xrl chugs at below 100kmh in top and so I usually change down to cruise at 90kmh. even then, I only get 62mpg and I used to get 65mpg when being gentle with my ZX9
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