[mpg_numbers_guy]

Thanks for the tip, both of you. I think I'll try 50 PSI first, and increase by 5 PSI up to 60 if they handle fine.

I think I found my new perfect driving technique - only doable at night when there's no traffic:
1. Accelerate to 40. To 30 in 2nd gear, 3rd gear 30-40.
2. Foot at 30% load in OD down to 30 MPH (75-85 MPG)
3. Neutral at 29 MPH down to 17 MPH.
4. Reaccelerate to 40 MPH from 17 MPH. 17MPH-30MPH in 2nd gear and 30 MPH-40 MPH in 3rd gear.

Netted me 64.3 MPG on a trip where my best was under 61. You should be able to travel a mile to two miles per "cycle". Instead of keeping a constant load you're demanding higher MPG and maintaining it for as long as possible.

However I won't be able to use this technique unless there is absolutely zero traffic, which is only at night after 10 PM (and I usually get out of work at 10:15p-11:45p so this might work most days). Personal driving is ~56 MPG for this tank so far, but I've been driving faster during pizza deliveries and getting ~38 MPG, so my tank is again only a little over 40 MPG.

It's officially past midnight now, so I can now say that I'll have my new wheels/tires on tomorrow (the 2nd)!!