Tractor Show Rules

Tractor styling by all companies changed radically in the early 1960s. Gone were the rounded hoods with bullet noses. Gone were the seats hanging over the drawbar. Diesels came on quite heavy by that time and they are a bit rich for a lot of hobbiests. I farmed most of my life with diesels, very efficient source of power. Today I just have three little gassers. Diesels can take a big chunk out of your pocket book when you step up to the parts counter. A lot of these clubs doing shows want to keep this hobby a low budget item.

Horsepower also took significant jumps in the 60s, by keeping it pre 1960s antique pulls get away with much lighter equipment. I don't think this is a very big factor as many of those sleds are very adjustable.

I don't think there is any one factor for this. I think 1960 has been the measure for a long time, even as far back as the mid 80s. You talk with old car and truck guys and most will tell you 25 years and it antique. They however don't have the longeviety of tractors or at least not in numbers.