When liquid ballasting tractor rear drive tires to enhance tractive effort and reduce wheel slip in heavy plowing:
Options:
(A) Tires are filled to approximately 75% of volume (level with valve stem in 12 o'clock position) with a solution of water and calcium chloride ($CaCl_2$) to prevent freezing and add density
(B) Tires are filled to 100% volume with pure engine oil
(C) Liquid ballast is applied exclusively to front steering tires
(D) Liquid ballast increases tire slip on firm agricultural soils
Answer Key:
A
Step-by-Step Solution & Explanation
Agricultural tires are liquid ballasted up to 75% of volume (covering the rim for rust prevention while leaving a 25% air cushion for tire compliance). Calcium chloride ($CaCl_2$) adds ~25% more weight per unit volume than water and prevents freezing down to sub-zero temperatures.