Bike came new with a Michelin no problems with tyre. 2nd tyre Dunlop was ok and was swapped round to wear both edges then finished a trial with it flat so was replaced as I thought it was punctured.3rd tyre new Dunlop went flat doing bemrose and came off rim and damaged valve inside rim and had to ride it off moors.just replaced with a new Dunlop d803gp and new valve checked rim no damage or mark's.rode Cleveland national and managed to do 20 sections then noticed it was flat and it pumped up ok rode rest of trial and was flat at last section! Blew it up to 10psi last night and just checked now and it's still at 10psi!