When replacing tires on a vehicle, it is recommended and preferred that all four tires be replaced at the same time for continued optimal vehicle performance. However, for those cases where this is not feasible, below are some general guidelines to consider when replacing less than four tires for a light vehicle, whether it is one or two tires. If the vehicle manufacturer has alternate recommendations, always follow their recommendations.
In some cases, the vehicle manufacturer may specifically advise against replacing less than all four tires. Always check and follow the recommendations in the vehicle owner’s manual. For 4WD and AWD vehicles, even small differences in outside diameter may cause drive-train damage or mechanical malfunction.
Replacing Two (2) Tires – When a pair of replacement tires is selected in the same size and construction as those on the vehicle, the two newer tires should be installed on the rear axles unless the new replacement tires are of a lower speed rating (see Dick Cepek General Tech Bulletin #7 “Tire Mixing”). Generally, new tires with deeper tread will provide better grip and evacuate water more effectively, which is important as a driver approaches hydroplaning situations. Placing greater traction on the rear axle on wet surfaces is necessary to prevent possible oversteer condition and possible loss of vehicle control, especially during sudden maneuvers.
Replacing One (1) Tire – Replacing a single tire on a vehicle can have adverse affect on suspension systems, gear ratios, transmission, and tire treadwear. If single tire replacement is unavoidable, it is recommended that the single new tire be paired with the tire that has the deepest tread and both be placed on the rear axle. Placing greater traction on the rear axle on wet surfaces is necessary to prevent a possible oversteer condition and possible loss of vehicle control, especially during sudden maneuvers.