Thanks very much for the comments lads. Adam, yeah i am working on getting smoother, i'm about 14 stone myself so no lightly. I'm not a heavy rider but could always be smoother, some of these flats have been ridiculous though - yesterday i hung up the tiniest bit up a set of stairs and it tore a huge hole in the tube! I think its a Maxxis tyre i've got on, but must be a single ply - only got the bike second hand a few weeks ago. Anyway cheers for the feedback, will probs go with try-all or a dual ply maxxis. Cheers!