Tech data on Mexican Hats
I used a late 7060 OM for some of this. Other 7000 and 8000 series tractors would be the same or very close.
Max tread normal 38" cast centers and non-power shift wheels, 18.4x38 or 20.8x38 = 115"
With power shift rims you get four more inches on each side = 123"
Mexican Hat cast centers, non-power shift = 136"
With power shift rims = 144"
So 10-1/2" of offset on each side.
Note: I have never seen Mexican Hats listed in specification equiped with non-power shift rims. Which doesn't mean they can't be set up that way, just you would not find them in the price book.
Weight of castings: I got my Mexican Hats from Russ Bishop at the time he had sold his Webster City Iowa A-C store. Also from Russ a set of about 11" thick inner wheel weights, similer to the A-C 450 pounders.
And from a area S-yard I purchased a set of later 7080 thick cast centers, 7" thick.
Also from the same S-yard, four of the A-C 450 pound cast inner weights.
After all this cast iron was home I made three trips to the Coop.
One with the thick inner weights - 1,190 pounds each. Let round it up to 1,200#. Coop scale breaks at 20#
Another trip with the Mexican Hats = Right at 800 pounds for the pair, or about 400# each.
Since Mexican Hats are about the same thickness as regular 38" cast centers, I would think the regular center would probably weight about 400 pounds each also.
Last trip was the 7" thick straight 38" cast centers.
Watch your back, as they weighted 1,900 pounds for the pair or about 950# each.
Then I got rid of that salty stuff in the tires.
Put a 1200 pounder on the inside of the inner castings. I used 3/4" all-tread for bolts.
And I made myself two sets of duals for the 7080.
A 20.8-38 tire and rim weight about 600 pounds, radials are quite a bit heaver.
So using the Mexican Hats, I had a set of 'Spring Duals'. Two 400# castings and two 600# rims with tires. Total about 2,000 pounds and good clearance between the tires, if I found myself in a wet spot.
The 'Fall Duals' are the thick straight castings, each with two 450 pound weights on the inside, 3/4" all-tread again.
So 2 ea thick cast centers - 1,900#
4 ea 450# A-C inner weights - 1,800"
and 2 ea 20.8-38 rims and tires - 1,200#
Bingo!! A set of nice and heavy 4,900# duals for hard pulling fall work.
It made my 7080 a pretty darn good rig on my White disk ripper with 5 DMI ripper shanks.
Or my 11 shank Allis-Chalmers model 1400 Min-Til.
Or my tile plow.
And then not a 'Steam Roller' for NH3 or the digger in the spring.
There are pictures of 7000 series tractors with Mexican Hat duals in some of the sales literature.
Also the early 220 sales literature has several pics of them.
I don't think there are any Mexican Hat pics in 8000 series sales literature.