i've had the OEM tires on my '07 Avalanche. i bought it almost the same time i bought my Roo HTT. in fact, i did my break-in period, driving to Chicago to pick up the Roo.
just turned 60,000 on them and they still have a good amount of tread left.
but, my Roo is well below the Avy's tow capacity(by 2,000lbs.) and it handles the Roo quite well.
if i was to tow something close to the max, i'd opt for a stronger tire.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC