I have almost 26k miles on my GL450 with stock 18" wheels/tires, bought December 2008. Tread depth is definitely down, but seems like I can get another year out of them maybe. Am I just looking at the wrong part of the tires? Where are our tires known to wear most? What's the most miles you've gotten out of the stock setup?

you are lucky that you have 26k miles and still some tread left. Mine didn't last longer than 20k miles. I have 19" wheels though.

there is no guessing... identify (usually by running your finger along the thread) the little wear bars in the threads- they look like small bars perpendicular to the thread channel. if the wear bar sits lower than the thread- your thread is good... if the wear bar is flush with the thread- time for new tires.

i have 19" on my gl and my tires lasted about 30k miles.

Very helpful advice. thanks.

30k miles already on my GL550 with 21" wheels . My Tech said I can put atleast 3k miles before I replace new tires .

IIRC, I got about 37K or so out of the 19" Contis. Replaced with Pirelli Scorpions. Better grip, but a bit noisier than the OEMs.

Folks here have gotten anywhere from 15-35K on their tires , but they all get noisy after 20K or so, doesn't matter how quiet any one brand is when new.

20k on my 20" runflats.