Even the name brand ST manufacturers recommend replacement at 3-5 yrs max, some even state be prepared to replace them at 3 yrs. I've had problems in the past even with Maxxis ST tires. So on my Cruiser I replaced the ST tires at 18 months with LTs. Since your Cruiser only has 5200 lb axles, LTs at load range E with 3042 lbs capacity per tire are more than enough and still 80 PSI. I went with BFG Commercial T/A's that are now 4 yrs old with 15k miles so far with no worries.