Dynamax Grand Sport GT Super C motorhome

Editor’s Note: The following product review authored by By Mark Quasius appears in the February issue of the Family Motor Coach Association’s (FMCA) Family Motor Coaching Magazine offering a look at the Grand Sport GT Super C motorhome from Dynamax. For the full article click here.

The Super C class of motorhomes can make a nice alternative to bus-style Type A motorhomes. A Super C utilizes heavy-duty diesel-powered chassis from the medium- or heavy-duty truck category. This gives the Super C greater cargo capacity, increased towing capability, and enhanced road handling in comparison to a typical Type A. Dynamax, a division of Forest River, offers a complete line of Super C motorhomes, with a reputation for quality workmanship and innovative engineering.

Dynamax’s Super C options range from entry-level units built on Freightliner’s medium-duty M2 chassis, with floor plans beginning at 30 feet long, up through 45-foot tandem-axle coaches utilizing Freightliner’s heavy-duty tandem-axle Cascadia chassis. For this review, we’ll cover a 40-foot Grand Sport GT, which is built on the latter.


The Cascadia chassis is commonly used for heavy-duty 18-wheelers. Dynamax custom orders this chassis to meet its motorhome specifications. A 15-liter Cummins ISX diesel engine provides 525 horsepower and 1,850 pound-feet of torque. The unit is ordered with a heavy-duty cooling system that will allow the engine to be chipped to 600 horsepower if desired. An Allison 4000 TRV six-speed automatic transmission passes the power to the 23,000-pound-rated R-series Quiet Ride rear axle.

Dynamax also specifies increased insulation in the engine compartment and firewall areas and 60mm Bilstein shocks to create a smooth yet stable ride. The smoothness is afforded by the Taperleaf front suspension and Airliner rear suspension. The Grand Sport comes standard with a 20,000-pound-rated trailer hitch, but my test coach was equipped with the optional 40,000-pound height-adjustable hitch, which includes air brake connections at the rear of the coach.

A pair of saddle-mounted fuel tanks gives the Grand Sport 140 gallons of fuel capacity. Both the fuel tanks and the 13-gallon driver’s-side DEF tank are hidden behind attractive fiberglass enclosures.

The cab is a driver’s dream. The instrument panel is filled with every possible gauge, and all controls are easily accessible. Overhead LED cab and map lighting can be switched on as white or red, for nighttime driving. A fog-line mirror is included over the passenger’s door, which allows the driver to see how close to the edge of the road the wheels are.

For the full article click here.