Amazon GC's for the win. 4 new General Grabber 31x10.5x15" tires at $149/each and free shipping. I did the mount and balance work so I saved there as well. Let me say that to date this is the single biggest improvement I have done to the truck. It's eye opening how much better the truck is with these tires on there. The tires I took off were Kumho Mohave AT's and some internet searching brings up a recall from 08-09 concerning characteristics round instability when cornering....while I doubt mine were from the recall window those characteristics exactly describe the tire.
So what is so much better:
1. Engine revs. The first thing I noticed in the first 500' of rolling on the new shoes was that I could actually spend some time accelerating in first gear. On the old tires first gear ran out almost as soon as the truck started to roll. Now I can actually get some speed before grabbing second. All gears are more usable and 4th gear is absolutely pleasant on the 50 mph roads. I did figure out that the speedometer is pretty close to stock except up around 50 - 55 and above when it seems to reveal its true deviation.
2. Bumps: Ride down road is smoother.. ..guessing a combination of rolling diameter and better tire construction. Mind you I still need shocks and bushings and maybe springs...so this wasn't a miracle cure.
3. turning: The old tires were really scary on corners....50 mph on a 50 mph road going into a corner.....turning the wheel turning the wheel turning the wheel...no steering response. New tires....turn the wheel truck changes direction.
4. Noise: The old tires were quiet and the new tires are quiet. Maybe I've heard a little more noise on the tarmac but so far its marginal. I'll see how they are when they are up around 65 mph.
5. Smoothness: The driveline pulsing is just about gone. With the smaller tires the I suffered from a lot of on/off/on/off throttle pulsing that feels like a combination of worn engine/trans mounts, slop in the gearbox, and carb tuning issues. With the bigger tires those pulses are either gone or greatly diminished. I still hope to go to EFI and get away from the carb.
Summary.....This change and this tire are great....guessing I'll get 40k miles out of a set which for me could be 10 years of driving. Even at the full price of ~$600 it is well worth it and For about 1/4 to 1/5 of the cost you get to reap the benefits of 5 speed like performance.
The one draw back so far is that I'm down a gear on hills because of the torque effects of driving a larger diameter tire.