The idea of a “tweener” or a baby 8 truck isn’t exactly new, but Mack’s approach with the Granite MHD is somewhat unique.
In many cases, a Class 6 or 7 unit is spec’d up to give the smaller truck enough power and capability to move upwards of 60,000 pounds. This lowers the sticker price but most often you’ll find a smaller cab, smaller mirrors, reduced visibility, fewer features and lighter components, including frame cross-members.
In the case of the Granite MHD, a standard Granite model is refitted with lighter components, like a Cummins 9-liter ISL, Allison 3000 RDS six-speed automatic transmission and in some cases lighter frame rails, axles and suspensions. The end result is a scaled down Class 8 truck, which provides a larger cab and increased rigidity.
Powered by Cummins’ lightweight ISL, the truck sits on a Mack Cornerstone chassis that features a high-strength steel frame.
The lighter-weight frame doesn’t sacrifice stiffness and performance. My drive on the surface roads of Indianapolis was highlighted with tight handling and more than enough power from the engine’s 345 hp and 1,050 lb. ft. torque.
Otherwise the MHD looks and is outfitted like any other Granite – comfortable, roomy and rugged with supreme visibility.
Granite MHD features flush and extended channel type front bumpers and hood splash shields to extend component life by keeping the engine compartment clean. My unit was outfitted with a 10’ by 36” snow plow, which added some head-weight to the truck, and the back was equipped with an 11’ dump box – a fairly common municipal spec for this truck.
The galvanized steel cab, coupled with the 9-liter ISL, makes for a quiet ride and mounting it on airbags and shocks means the truck absorbs most of the battering before it reaches the driver.
With a tight steering radius, Granite MHD easily navigates narrow streets, crowded jobsites and makes quick work of plowing a small patch of snow from the Indianapolis Zoo parking lot.
All baby 8s are built to take a beating, but Mack’s Granite MHD is a heavyweight fighting in the middleweight division, allowing it to take one across the teeth time and time again.
By Jason Cannon, March 15, 2017