John
I think I would change them all.We had one on a 2011 trailer that the tread started to swell.I found it when I pulled into a camp ground.we were not that far from home on that trip so put the spare on before we headed home.When I took it off the rim and looked a it the inside lining had a wrinkle in it like the whole tire had swelled and had stretched the inter liner.I had always replaced the China may pops when I bought a trailer until this one and the wife was on my case about putting new tires on less than a year old trailer and I thought maybe I am making to much out of it.But this proved me wrong.Tires were built in Aug 2010.
