I've got a few leftover sets from when I helped the now defunct Vajra with their Buffalo. Even though they are 1/35, because they are so large they scale out perfectly on a 1/32 frame. There are wheels sets made for the current Bronco Buffalo which will work as well. (And probably the Meng Cougar.)
I was unable to visit that link provided above as I was on an iPad at the time (and thus do not know how to cut and paste) but I've since visited the site and those 1/25 Michelins look great. The guy I'm building this for
may want me to switch to 1/25 if he finds out)

I'm glad that site was posted - I found it quite by accident several months ago and discovered they make a US recoilless rifle which will work perfectly with my old MPC "Korean War Jeep," and then couldn't find it again.
The tires from Legend Productions or Kinetics Maxx Pro are also the correct pattern, but with a smaller diameter. They also don't have the deep rear hubs you need, so I'd say go with Buffalo resin wheels if you want to go the 1/32 route.
At any rate, if I do end up building a 1/25 War Rig, I'll probably finish out my 1/32 one for myself now that I've started it. Please see parts request in Buy Sell Trade forum.