[Bitza]

Hi All, Well this is a bit of a weird one, does anyone happen to have an idea of how much weight tyres loose when worn? I'll explain, just prior to a total revamp of my bike I weighed it, then changed to a heavier engine lump & rear wheel plus weight saving measures with the aim of ending up with the same weight machine, easy? but then I realised that I had started with totally knackered tyres and would end up with brand new ones, so I NEED some kind of guess to correct my estimation, and no messing around with your answers please, Bitza.