Well I got 680 hours on them, mostly on turf. but today was the day. I was just finished with my last pass of the week and I felt a spongy feeling. Looked to the side and there she was blowing air. I obviously caught something across the sidewall and made a small slit (less than 1/2"). They were TITAN 4 plys 18-9.50-8 on my Walker. I need to have tires for Tuesday and with the holiday coming on Monday, I was pinched. There is only one place in my area that had tires for me so I picked two of them up. I am not sure if there will be a problem but they are 2 ply tires. I do lots of hills and wonder if there will be a problem? I also notice that the 2 plys have a max inflation of 12lbs and my 4 plys are at 24lbs max. I always run them around 16-18 anyway. I tried a search with lots of mention of tires but nothing like this. What do you think?