denali16

I'm using a gps speedometer app on my phone. GPS is pretty accurate as long as you get good signal and stay at a steady speed. I've also done the math based on gears and actual tire size etc but primarily the former.

I've read (and been told by dealers) that the dealer will not recal the speedo unless its with a factory optional size. My speedo is off when I put on 275/60/20s but i recently bought a hypertech speedo recal. Not the power programmer but just the tire/gear speedo recal. Got it for about 175$ from an online store with free shipping (PM me if u want to know which), cheapest i could find. It works well and don't have to worry about voiding warranty as I'm told the newer trucks computer keeps logs of all changes and they can void your warranty if something goes wrong after using a power tuning programmer. There are documented exceptions to this but personally for a few HP i'm not risking the warranty. I'm a programmer by trade and its amazing how much and what can be recorded these days.

Good question, I was a bit concerned my self but I actually had vibration issues with the OEM GY eagle LS2's so I couldn't wait to get them off (had them off before 500 miles on the odo). With that said, the comfort level is better imo as they're smooth as glass especially on the highway which was honestly surprising. Its about a 5-10% stiffer ride I guess one could say (depending on what psi being run) as they're a bit heavier than oem and with the windows down I do hear a little bit of road noise (maybe 15% over OEM) but with the noise cancellation tech in the truck I honestly can't hear anything different with the windows up. I'm running about 39-42 psi and I honestly couldn't ask for a better tire. I had Nitto Terra Grappler G2's on my 14 Jeep Grand cherokee and they made more noise than these tires which is shocking to me. Could be the difference in vehicle or whatever but I'm glad I went with the KO2's over the Nittos. Not to mention they look better *IMO*.

I've been lurking here for a while but figured i'd throw my new truck in the mix. 2016 Sierra Denali 6.2 4x4 all stock with the exception of BFGoodrich All Terrain T/A KO2 tires in 275/60R20 and drop in K&N filter. No lift, no level, no scrubbing at all.