I noticed that my truck came stock with 31x10.5x15s... I was under the impression that Blazers came stock with 29s?? After looking over the mileage chart at 4lo.com, I'm just wondering if it's possible that my truck not only came with 31s, but with 4.11 gears as well?? It's a dog on accelleration, and in 3rd (465 with Low) gear, it doesn't get up and go really well, but it can accellerate from 65-85 in a few seconds. I had the rearend rebuilt... but I don't think the shop ever looked at the ratio.... so I can't even ask them what it is... I'll know for sure when I change my diff case oil this summer, but I need "educated guesses" right now.