So today I was fitting a new 1/4 bandsaw blade. Placed the gullet central on the tyre, spun a few turns and the blade is in the front edge. Try again same result. So backed off all the guides. Tried again same thing. Tried several times more hoping for a different result. So I went and had a cuppa tried again same thing. So I completely untensioned the bandsaw and started from scratch. Perfect. All I can assume was there was too much tension which was pulling the blade down the tyre.