Originally Posted by pjpvi
I don't think you should have any problem going to 305's if you have the SMB 4x4.
I currently have this setup (315/75/16) that came from SMB and mine is a SMB 4x4 build. No problems at all with clearance or rubbing with the 35" tires. You could probably even fit a 37" under there barely without a problem... in fact I think badger did as well as a few others on here. The only problem would be mounting the spare on the back as I am maxed with the 35" on there right now. I think with a 37" spare it wouldn't close with the aluminess tire carrier and box.
However with the V10 the 37" might be pushing it. Even with the 35" I have currently on the van, it is about 100 lbs per tire compared to about 70-75 lbs per tire for a 305/70/16 tire. This translates to harder braking and more engine lag. I have the 4:10 gear setup.