I bought my tires from Bast on Lobsinger Line (right beside where I bought the trailer). They were Goodyear Marathon ST225/75R15... same size as the 'Power Touring' that came on it. They also recommended Carlisle tires, which get acceptable marks here but I asked for the Goodyears (which they had to have shipped in so I knew they hadn't been sitting around long). I keep them covered whenever the trailer is in the driveway and they are in great shape. After each winter, the pressures are all still identical and had not lost any air since the fall. Goodyear now makes an ST tire called the Endurance in the U.S. and that may by my replacement when these are up.