I have the standard 4.00-12, 4 ply, tri-rib tires on the front of my L2201. The problem I have is that I am constantly getting flat tires from thorns. It seems like the rubber is just really soft. What can I replace them with that will be tougher? I can't find anything in that size with a higher ply rating. I thought about a 4.80-12 trailer tire, but wasn't sure if that would be too wide for the 3" wheel. Any suggestions?