new to MM

These highly collectible tractors were designed and produced after the formation of the Minneapolis-Moline Power Implement Company in 1929.

The Minneapolis-Moline Power Implement Company was formed by the merger of three old line farm machinery companies, the oldest dating back to 1865. The Moline Plow Company, the Minneapolis Threshing Machine Company and the Minneapolis Steel and Machinery company were united by economic necessity. After the 1929 merger, development was begun on the M-M line of tractors which became known as the prairie gold "letter" models �Z�, �R�, �U�, & �G.� These took several years after the 1929 merger to develop and bring to market. From the 1929 merger until the late 1930's MM sold the tractors previously built by two of its parent companies as the MM Twin-City brand and as the Minneapolis brand. These Twin City and Minneapolis brands continued to use their old letter and number desiginations. MM never sold any tractors built by the Moline Plow Company.

Explanation of Minneapolis-Moline�s �three letter� designation:

Colloquially we refer to MM tractors by one letter, but officially, the prairie-gold and M-M cherry-red "letter" tractors were designated by three (or more) letters (example ZTU, ZTN, ZTS, ZTI, or ZTI-M.) Often the first letter designated a size-model, the second letter a series, and the third letter a chassis and front end type. Serial number plates may not include all three letters. Experience shows that all three letters typically appear on tractors during the early to late forties, but usually only the first or first and second letters are shown on tractors after that time. However, some of the very early serial plates did not have all three letters either. For instance, early 1939 R's often have just RT stamped in the data plate regardless of the front end type. The later model R's often have just "R" stamped in the data plate--no "T" and no front end designation. "ZA"s and "ZB"s often have just "Z" stamped on their serial data plates.

Explanation of the First letter: (models) RTI, ZTU, UBE, GTB

The �R� model was the smallest and was designed to be a one to two-plow tractor. The "R" was first rated at 23.22 belt hp on gas. It was later re-rated at 27.09 belt hp.

The �Z� model was the next size and was designed as a two to three plow tractor. In 1937, the "Z" was rated at 26.84 belt hp on distillate. By 1950, the "Z" was rated at 36.20 belt hp on gas.

The �U� model was designed as a three to four plow tractor. In 1938, the UTS was rated at 36.48 belt hp on distillate and 42.88 belt hp on gas. In 1939, the UTU was rated at 42.71 belt hp on gas. In 1941, the U was rated at 46.87 belt hp on LPG. In 1954, the U was rated at 37.23 belt hp on tractor fuel. In 1954, the UB was rated at 48.38 belt hp on gas and 51.27 belt hp on LPG.

The �G� was a four to five plow tractor. In 1942 the GTA was rated at 56 belt hp. By 1955, the GB was rated at 74.95 belt hp on LPG.

In 1951 M-M purchased the BF Avery company and began selling the M-M models BF, BG, and V, which were principally one or two plow Avery tractors painted in the M-M prairie gold color and sold as M-M. Derivations of the BF were sold until 1955. These tractors are very popular with collectors. Their small size and lighter weight for �show-hauling� purposes is a plus. The Avery M-M�s took their letter names from Avery derivations and do not follow any rules. The Avery "R" was changed to the "BF" because MM already had an "R" in its lineup. BF was chosen in honor of B.F. Avery, founder of the company.

Explanation of the �Series� letter:

ZT, ZA, ZB;
RT; UT, UB, UB Special, UT-D,
GT, GTA, GTB, GTB-Diesel, GTC, GB, GB-Diesel

The second letter usually designated the series (see the "G" exception below.) Each subsequent series was improved mechanically, in horsepower, and in other options over its predecessor. The first series was the �T� series ("ZT", �RT�, "UT", and "GT".) "T" stood for Tractor. Subsequent series letters started with "A" and followed in alphabetical order. M-M tried to keep the series letters the same (or close to the same) for all of its models. The ZT became the ZA which became the ZB. The first Z series was the Visionlined ZT 1936-1948, the second �Z� series was the ZA 1949-1953, & the third was the ZB 1954-1955. In 1953, M-M elected to skip the �UA� series because they didn't want to have a ZB and a UA in the same year. To be consistent the second "U" series was the UB. This was because the ZB was introduced in the same year that the second series of the �U� was introduced, and ZB and UB was more consistent for the same model year. In the �G� models from 1942 until 1954, a third letter was added to designate improved series. The �GT� (1940-42) became the GTA (1942-47) which became the GTB (1947-53) and the GTC (1951-53) followed by the GB (1955-59.)As you can see the model years had nothing to do with the years of production of the series. Thus MM often had in its lineup the second or third series in one model while still selling the first series in another model. In some cases (for example UT and UB) two series were available for several years at the same time.

Explanation of the Third letter: ZTU, UTS, RTN, ZAI, ZAE

The third letter designated a chassis and front end type in the U, R, & Z models (G's were an exception to this rule.) Type �U� is a universal, narrow front with two front tires. Type �N� is a narrow universal front with a single tire. Type �S� is a standard front with two wide non-adjustable front tires. Type �I� was an industrial standard front tractor. Type �E� is a wide front with extendible tire tread width from 56 to 84 inches at 4� intervals. In other cases third letter M means Military, C means Cane (hicrop,) and O means Orchard. All G�s had a standard front end and chassis therefore their third letter formed an exception to the chassis/front end third letter rule and designated a series as explained above.

Type N single front wheel tractors were useful for special row crops such as potatoes, however they were often converted to another front end type before they were sold. This was done because the single wheel models were very hard to steer when the single wheel mired into soft soil. This conversion was often done by a dealer when the tractor was still new, so the first owner may never have known that it was originally a single front wheel model. Front end Type U (two narrow front wheels) was very popular, as it was the most versatile. They were taller, could steer between row crops, turn on a dime, as well as adequately do the heavy disking often relegated to standard front models.

Hope this has not been too confusing, but in the MM world it is best to remember one rule, "There is an exception to every rule."

Good Luck
John in Georgia