I don't know. They roar and vibrate and do all sorts of cool things enough that I never really noticed any sidewall "squirm". Driving like a sports car + Swampers = Dead. <img src="/forums/images/graemlins/notooth.gif" alt="" />
From my experience, however, the SXs ride far worse than a standard TSL because (when you do get one that's out of round, as seems to happen 50% or so of the time) they are noticeably worse than the standard TSL because of the extra mass of the steel plies.

I think everyone already knows, but my experience is comparing the 36x12.50 TSL to the 38.6x14.50 SX - and that's not exactly appes-to-apples.

Don't get me wrong: I love my SXs. But IMO, if road wear is enough of a priority to even bring up, get TSLs. I loved my 36" TSLs... they were just too tiny after a while. TSLs are still extremely durable as far as puncture resistance, but they rode much nicer and WEIGHED a lot less. I think on a DD rig with low HP like a Toyota, the TSl is a better buy. Anyone whose converted to a swamper from a radial tire can attest to it feeling like someone welded a restrictor plate into the exhaust. The weight makes a huge difference.

Oh, and Harry: Radials suck.