Tire manufacturers continue to make their farm tires larger to support the additional weight of farm machinery, which has grown in size. Up until 2009, the largest size category on the replacement tire market was Group 48, defined by a rolling circumference of 243 in. and an overall diameter of 81 in. — think 6 ft. 8 in. tall. But this year tire makers are starting to produce even bigger tires categorized at Group 49, which are 7 ft. tall and have a rolling circumference index of 256 in.

One example is the Goodyear DT930 1100/45R46 radial tire, launched by Titan-Goodyear in March.  Designed for combines, tractors and grain carts, it is currently the industry’s largest farm tire. Titan says an even bigger tire — Group 50 — is in the works and could be available as early as next year. For more information, visit www.titan-intl.com.