Alternatively, Lots of Masseys and some Fords used the same bolt pattern (6" pilot hole with 8 bolts on an 8" bolt circle). Probably more Massey/Ford rims out there than Allis. Be careful though: Some Fords used a 5.5" pilot hole.

I'm a big fan of changing from 28's to a more standard size. But are you sure you want to go as large as 34"? If so, you'd probably have to stick to 16.9's and not 18.4's, as 18.4-34 will be a huge height increase, look weird, and might present some fender fitting issues.

I'd recommend going to 18.4-30's. They're only a tiny bit smaller diameter than 16.9-34's, but a fair bit larger than the original 28's. They also have a much larger contact patch than the 16.9's, so you'll get  better floatation. In fact, going from the original Allis 18.4-28 to 16.9-34's will actually give you less ground contact/floatation. Plus, Allis made a 30" option for the 180, so you might even find original Allis power-shift rims (though they're hard to come by, which is why I did my conversion differently). The picture in the link above is my 180 with 18.4-30's on it.

I encourage you to go with the 18.4-30 option.  Our 1975 185 arrived that way from the factory and that provided great traction, stability, and wear for many years.  It also seemed to be the most popular option for rear wheel sizing for the 185.

CORLEWFARM wrote: I have a 180 with original 38 in wheels. 15.5 38 works for better speed and I think better traction than our tractors with 18,4 30

CORLEFARM, I've never liked the 15.5x38 tire size, I'll keep the 18.4x30's on my 185. They are Titan's, which is NOT my favorite tire but they are tall.

15.5's have a low section height for whatever reason. If they were steer tires they would be 15.5Lx38.

Thanks. 

 My Father upgraded the original front tires, as did many AC tractor owners, from the factory 7.50-16 to 10.0-16 and reversed the rims.  I have tried to keep the tractor as original as possible. 

Hopefully, our comments helps SteveMaskey(MO) with his project