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2007 Allegro Bus 42QRP

Road Test, Review and In-Depth Inspection
Article Date: July, 2006


The Chassis

This unit came with the Spartan Mountain Master GT tag axle chassis. Both Spartan and Freightliner both use the Cummins 400 ISL engine and Allison 3000 transmission. There are differences in the front suspension and steering component vendors but this isn't very significant. The adjustable steering wheel is controlled by a pedal on the Freightliner and by a lever on the Spartan. The wheelbase is identical between the two. The wheelbase from the drive axle to the steer axle is 283". The tag axle sits exactly 48" behind the drive axle. Some chassis builders rate the wheelbase from the front axle to the mid-point between the two rear axles. If this is the number you prefer to use, then 307" would be that number. The wheel rims on the tag axles do differ between the two. Both chassis builders utilize rear drum brakes but Freightliner uses air disc brakes on the front axle while Spartan uses drums. However, Spartan's 5" wide shoes are larger than the 4" wide shoes typically used so you probably won't notice much difference in stopping power.

Freightliner mounts the tag axle rims the same as the steer axle while Spartan mounts the tag axle rims the same as the drive axle. Either method works but the style is different. My personal preference is the 18 wheeler look of the Spartan.


When you open the rear engine access covers you'll immediately notice the difference between the Freightliner and Spartan. The plastic coolant surge tank located dead center in the Freightliner is replaced by a steel surge tank with glass sight vial in the Spartan. This tank is located off to one side to enable better access to the engine for changing belts or other tasks. The fuel and coolant filters are conveniently located right at the rear of the coach so you won't have fuel running down your arm any more when changing the filter.


The biggest difference between the two is in the cooling systems. Freightliner has a 39" x 22" radiator grill with a 1,050 sq in radiator. Unfortunately, the Charge Air Cooler, air conditioning, and transmission cooler are all stacked in series. This tends to transfer heat from one cooler to the next. Spartan uses a vertically stacked cooler design so that clean airflow is provided to each cooler. The radiator is much larger in the Spartan and at 1,326 sq in it should help alleviate some of the cooling issues common to Freightliner based Allegro Busses in the past. The grill area is increased to 46" x 27" to accommodate this increased cooling capability. In the picture below you can see the row of bolts behind the grill that separate the radiator from the CAC.


While not shown in any of the above images. I noticed a distinct difference in the fuel fill hoses between a 2006 42QDP/FL and the 2007 QRP/Spartan. The Spartan fill hoses have a definite slope to them whereas the Freightliner hoses had a sag to them and had to run up to get to the fuel tanks. The clean pitched drop on the Spartan tank should eliminate some of the past issues with getting enough fuel into the tank and minimize foaming.

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