I have 275/70R 18 Toyo Open Country A/T's on my 08 4x4 DC. I have 15k miles on them and just rotated them for the first time two weeks ago. The tread depth is between 12 and 14/32, they were 16/32 new. I drive my truck pretty hard, and these tires are holding up well in my opinion. They are great in wet conditions and off road use. My only complaint, is that they can be difficult to balance on the stock aluminum rims that I have. But I guess that is more of a rim issue than tire issue.

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2008 Double Cab 5.7 4X4 SR5
MODS: OEM Backup Camera UWS low profile Tool Box, UWS Stainless Step Bars, Toyota Bed Extender, Magnaflow dual/dual Stainless Exhaust, K&N Filter, Toyo A/T Tires