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Technical Bulletins

Tractor Tire – Front R-1 Drive Tire Wear

Due to the design and function of mechanically driven front wheel drive tractors, certain conditions could exist which can cause irregular or rapid front tire wear.

The front drive tires are smaller than the rear drive tires and are designed to run at an overspeed of 1% to 5% over that of the rear tires in order to obtain maximum contribution of the front drive axle. This overspeed, combined with front-end alignment factors and steering forces, creates conditions under which the front drive tires could wear at about twice the rate of the rear tires. If a tractor exhibits irregular or rapid front tire wear, the following corrective action should be taken:

  1. Check front-end alignment and set per vehicle manufacturer's recommendations. R-1 lug bar designs are especially sensitive to improper toe adjustment of the front end. 
  2. If the front wheel drive is the type which can be engaged or disengaged by the operator, check for proper operation of the engaging device and proper usage by the operator. If the tractor is operated on pavement with the front axle engaged, tire scuffing will occur with premature tire wear resulting. When operating on pavement, the front axle should be disengaged to reduce front tire wear.  
  3. Check for proper matching of front and rear tires for correct overspeed. Tire rolling circumference matching between front and rear axle is very critical to tire and drive train performance. Make sure that the tires on the tractor are a combination that is recommended by the vehicle manufacturer for the specific model. When replacing tires, both tires on the same axle should be replaced to insure matched static loaded radius dimensions.  
  4. Check for correct tire inflation pressure. Front tire pressure should be maintained at maximum allowable level. (Check the load tables in the Firestone Data Book for inflation pressure.)
  5. Check tractor for proper load distribution. Follow the recommendations given in the tractor operator's manual. Generally a 40% front / 60% rear weight distribution ratio is recommended.