Increase in MPG/K&N

[richfzs]

The second bit makes some sense.

The first one though, I put winter tyres on the cage, which have blocks so soft you can move them with a single finger pressure, and get no difference in mileage between winter and summer (always filling the tank, and recording mileage at each fill), so am struggling to believe that one, especially as the blocks on most bike tyres are so large...

Thanks for answering :-)