Frame engine cutouts shall be made with a plasma torch to minimize the heat affected zone of the
cut. All cutouts shall have a minimum of 6 inch transitions between rail flange cut depths to reduce
the stress concentrations throughout the cutout area. The root of all transition areas shall have a
minimum of a 2 inch radius to reduce stress concentrations at the root.
The frame rails shall be powder coated prior to chassis painting to reduce the effect of harsh road
chemicals.
CROSSMEMBERS
In addition to the rear cab support cross member there shall be a main frame cross member
mounted in the rear cab area. Every frame cross member shall be bolted in place using grade 8
bolts, hardened washers, and grade "C" distorted thread locknuts.
FRONT AXLE
The front axle shall be a MERITOR model "MFS-18-133A-N" with an 18,740 lb. capacity.
CRAMP ANGLE
The chassis shall have a turning cramp angle of 52-degrees. Both left and right turns have a full 52°
cramp angle with tires and wheels mounted on the axle and installed in the chassis. The 52°cramp
angle is achieved irrespective of options.
FRONT AXLE OIL SEALS
The front axle shall be equipped with oil bath type oil seals as supplied on the axle from the axle
manufacturer. The spindles shall be equipped with transparent covers for oil level inspection.
FRONT AXLE BRAKES
The front brakes shall be Cam-Master Q Plus, 16-1/2" X 6" S-Cam, air operated heavy duty brakes
with automatic slack adjusters.
FRONT SUSPENSION
The front suspension shall be a pin and shackle design. Front springs shall be a minimum of ten
(10) leaf elliptical type, 53" x 3-1/2" x .499" forged steel. The front springs shall have a military
wrapper for safe operation. For a smooth ride the spring rate shall not exceed 3,000 lbs/in
deflection.
All front spring pins shall be ground heat treated steel with grease fittings for lubrication.
The entire front suspension shall be designed for heavy duty custom fire apparatus with a capacity
at ground of 18,740 lbs. Double acting hydraulic shock absorbers are to be installed.
STEERING SYSTEM
The steering shall be equipped with a single SHEPPARD M110 integral power steering gear. A
remote steel reservoir shall be provided with the ability to check the fluid level when the cab is in
the lowered position.
FRONT TIRES
The front tires shall be 315/80R22.5-20PR (L) GOODYEAR G-287 MSA all weather tread,
tubeless radial tires...
