2007 ORS § 801.520¹
"Tandem axles"

"Tandem axles" means any two or more consecutive axles that have centers more than 40 inches but not more than 96 inches apart and:

(1) Are individually attached to or articulated from, or both, a common attachment to the vehicle; or

(2) Have a connecting mechanism designed to equalize the load between axles. [1983 c.338 §94; 1985 c.172 §3]