EP 1110-1-8
(Vol. 2)
31 July 03
2.26
Tire Cost
Tires included on rubber-tired equipment are generally the type and ply rating
recommended as standard tires by the equipment manufacturer. Tire costs include
both tire wear (replacement) and tire repair as individual elements of cost. Conveyor
belt wear is also included under this cost element.
a. Tire Wear Cost. The formula for calculating tire wear applies to each tire
position: front (FT), drive (DT), and trailing (TT). However, all tires performing the drive
function are considered drive tires and are listed in the drive position. The total hourly
tire wear cost for each unit of equipment is the sum of the hourly cost for each position.
The total hourly tire wear cost equals the current cost of new tires plus the cost of one
recapping divided by the expected life of the new tires plus the life of the recapped tires.
This hourly allowance for determining tire wear cost is expressed in the following
formula:
Tire Cost Factor x Current Tire Cost
Tire Wear Cost/hr =
Tire Life Factor x Tire Wear Factor x Maximum Tire Life
Where:
(1) Tire Cost Factor is estimated at 1.5, which represents the purchase of
the original tire plus one recap. It has been estimated that a recap costs approximately
50 percent of the new tire cost.
(2) Current Tire Cost is the estimated cost that applies to all tires on the
equipment in that position. For example, four new drive tires valued at 0 each would
result in an amount of ,000 for total drive tire cost. The size and cost of each tire
used in the pamphlet are listed for information in appendix F.
(3) Tire Life Factor is estimated at 1.8, which represents the original tire
life plus one recap. It has been estimated that a recap lasts approximately 80 percent
of the life of a new tire.
(4) Tire Wear Factor is based on the position of the tire, type of
equipment, and condition of use. Tire wear factors have been developed and are listed
in appendix D. These factors will provide a percentage reduction to the maximum tire
life. Appendix G contains the methodology used to develop these factors and a
computation example for a rear dump wagon.
(5) Maximum Tire Life expressed in hours is shown for various new tire
types in appendix F and appendix G. The tire life is estimated from information
provided by Goodyear Tire and Rubber Company and by using the method and tables
in Production and Cost Estimating of Material Movement with Earthmoving Equipment,
Terex Corporation, Hudson, Ohio.
b. Tire Repair Cost. It has been estimated that tire repairs are 15 percent of
the total hourly tire wear cost. The LAF is used to adjust the tire repair cost to account
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