attachment 2 section i ? technical specifications commuter coach ...

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ATTACHMENT 2
The steering wheel shall be not less than 19.5 inches in diameter and shall be shaped for firm grip with
comfort for long periods of time and shall not be padded. The steering wheel shall be removable with a
standard or universal puller. Hydraulically assisted power steering shall be provided. The steering gear
shall be an integral type with flexible lines eliminated or the number and length minimized. Steering
torque applied by the driver shall not exceed 10-foot-pounds with the front wheels straight ahead to
turned 10 degrees. Steering torque may increase to 70-foot-pounds when the wheels are approaching
the steering stops. Steering effort shall be measured with the coach at SLW, stopped with the brakes
released and the engine at normal idling speed on clean, dry, level, commercial asphalt pavement and
the tires inflated to recommended pressure. Power steering failure shall not result in loss of steering
control. With the coach in operation, the steering effort shall not exceed 55 pounds at the steering
wheel rim and perceived free play in the steering system shall not materially increase as a result of
power assist failure.
Caster angle shall be selected to provide a tendency for the return of the front wheels to the straight
position with minimal assistance from the driver.
3.5 BRAKES
3.5.1 SERVICE BRAKE
3.5.1.1 ACTUATION
Service brakes shall be controlled and actuated by an air system. Force to activate the brake pedal
control shall be an essentially linear function of the coach deceleration rate. The angle of the pedal
shall be ergonomically designed to minimize fatigue. At least six (6") inches of slack in the airlines
shall be available to allow for change out of the brake treadle valve and pedal assembly. The brake
pedal shall be slightly lower than the accelerator. Provisions at the front shall be made to activate the
brakes from the towing vehicle. Release of the emergency/parking brake shall require one full
application of the service brake once the emergency/parking brake release valve is depressed. A
protective bracket shall be added to the secondary emergency release valve.
3.5.1.2 FRICTION MATERIAL
Brake lining shall be non-asbestos Carlisle brake lining, and must be designed and approved for use on
the vehicle being proposed. All brake linings shall be standard tapered Q-Plus lining. Brake lining
must provide optimum performance with the brake system being used and shall minimize brake noise
under all weather conditions. Riveted linings are acceptable. The brake system shall be equipped with
Meritor, automatic slack adjusters.
3.5.1.3 HUBS AND DRUMS
Wheel bearing seals shall have integral replaceable wear surfaces. Wheel bearings and hubs shall be oil
lubricated. Use of disc brakes shall not be permitted on any axle.
3.5.1.4 ANTILOCK BRAKE SYSTEM