Hmm.... yes the Frenchie! Another build I have stumbled upon that I enjoyed. Here is the build and the Indy wheels are in the there towards the beginning or middle.
http://www.rc-monster.com/forum/showthread.php?t=22113
Here is a bit from the email I received from Rick (the SPI Racing wheels guy). I asked him what the dimensions were for the F-1 and the Onix wheels and what size tires fit them, and he responded with this...
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From SPI -
"Standard Monster Truck size. 3.2 mounting diameter and 2.2 wide. All
of them are the same size. The big thing is the offset. 1-5/16 farther
out than stock. This is what make your truck turn so fast and keeps it
from rolling up on its side."
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All the SPI monster truck rims are the same size - 3.2" outer diameter. So after a quick search through Towers stuff, I believe that the 3.2" are the old Maxx and 3.8" are on the new 3905 versions.
Old stock Maxx tires (3.2):
http://www3.towerhobbies.com/cgi-bin...?&I=LXJG97&P=7
New stock Maxx tires (3.8):
http://www3.towerhobbies.com/cgi-bin...?&I=LXMJF0&P=7