Unit 27: JD 9420 R Tractor w IF800/70R38 Duals Posted on January 21, 2019 (January 21, 2022) by Alex Barrie in Compaction Test Results Datasheets Plot Comments This Unit is a very nice demonstration of well balance duals on an articulated tractorThis setup did not have much weight on the tractor and draft load from any equipment would increase the pressure on the rear tires.