Western Star's Twin-Steer 6900 XD: Go big or don't go
Western Star Trucks
When you’re axle-deep in mud or traversing the steep slopes of a quarry or a mine, Cary Gatzke’s attitude is go big or don’t go. Gatzke, director of engineering at Western Star, says that’s the ethic behind the 141-inch BBC Twin-Steer 6900 XD, the highest-capacity truck Western Star has ever built.
The Twin-Steer 6900 XD has a gross vehicle weight rating of 146,000 pounds—36,000 pounds on the front axles and 110,000 pounds on the rears. Standard axles are Eaton’s EFA 22-T2 for the front non-drive steer axle, a Sisu FSDP-14G for the front drive steer axle, and the Meritor SPRC 1927 for the drive axles. You can spec all-wheel-drive and 8x6-drive configurations if you need more pull.
But size isn’t everything. With its twin 40-degree wheel cuts and set-back axle, the Twin-Steer 6900 XD is a nimble machine. It has two independent steering systems and four asymmetrical taper leaf slipper springs with four parallel torque rods that control each front steer axle. The non-torque-reactive front suspension design controls bump steer, produces less steering wheel feedback, and improves tire wear.
Introduced in March 2000, the 6900 XD line replaced Western Star’s Heritage Series trucks for mining, oilfield service, and military applications—traditional markets for Western Star both here and abroad. The 6900 cab, radiator, and engine were raised in relation to the frame by more than three inches, allowing the frame rails to extend intact under the radiator. The cab was moved back to position the engine entirely in front of the firewall, reducing the risk of damage to critical components and easier servicing of the engine and under-hood systems.
The Twin-Steer 6900 XD complements Western Star’s 4900 SA twin-steer trucks in both 109-inch and 123-inch BBC.