Obviously some Kendas aren't good, but there's absolutely no basis to conclude that all Kendas are junk because of a few anecdotal failures. You can find anecdotal evidence of failures of any tire but you rarely hear of good examples because ... why would anybody post a good example? Well, I will. I have 4200 miles on my Kendas and I have no vibration, they track straight, and they look like brand new. Why are mine good and others have problems? Dunno. Do we ALL maintain proper air pressure ALL the time? Do we ALL always avoid the "tyre gators" that Spyderlass mentioned? Do we ALL drive under the same temperatures, weather, speeds, on the same roads, etc.? Emphatically NO. That alone is enough to dispel this ridiculous generalization. And consider this - BRP built the Spyder with competent engineers and if their engineers aren't experts, then none of us should never climb aboard a Spyder because they're obviously far too dangerous ... right??? If Kendas are as dangerous as some people here claim, BRP would be sued nine ways to Sunday. Ever heard of such a lawsuit? Me neither.
Are there some bad Kendas? Yes, of course, just like you can find bad tires by any manufacturer. Maybe some "need" to run out and replace their Kendas. Others don't, so enough of the generalizations. This is the same kind of "wisdom" here that tells you that everyone "needs" a laser alignment and everyone "needs" a BajaRon sway bar and everyone "needs" that thingie that supposedly prevents the belt vibration that I never feel. Maybe some do need these things, but when somebody tells you there is a problem it's really easy to start imagining that you have it, too. I myself was ready to fall for this stuff until I did a ryde where I was doing 80 mph on the freeway for a couple of hundred miles without a bit of vibration and I came home and exited the freeway on a flyover where I was passing cars at 65 mph and having a grand old time. It was then that I realized how fantastic my factory-original Spyder with plain old Kenda tires was and WTF would I want to mess with it? "If it ain't broke, don't fix it."