Specifications

REQUEST FOR PROPOSALS FOR
PURCHASE AND DELIVERY OF HEAVY-DUTY BUSES
RFP SRTA-2014-01
TECHNICAL SPECIFICATIONS
PAGE-8
December 2013
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e. Axle shafts shall be the floating type with all wheel bearing loads carried on the
axle housing end sleeves.
f. The drive flanges at the outer end shall be attached to wheel hubs by studs, nuts
and tapered dowels. Axle hubs shall be stud wheel pilot mounting.
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g. Wheel bearings shall utilize "wet" lubrication.
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8.3 Rear Axle Gear Ratio
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The differential gear ratio is subject to approval by the SRTA prior to production after
reviewing computer generated performance scans for the buses offered.
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8.4 Hubodometer
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An Engler (Stemco) Hubodometer "million mile" (no tenths), or approved equal, shall be
installed with the correct bracket on curbside rear axle flange studs.
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8.5 Wheels and Tires
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a. The coach shall be equipped with single front and dual rear wheels. Front wheels
and tires shall be balanced and counter weighted where necessary. Alcoa
Aluminum wheels (p/n 883110DB) with “Dura-Brite” surface treatment, 8.25 x
22.5, satin machine finished stud (budd) piloted wheels, or approved equal,
shall be provided. Steel wheels may be an alternative to aluminum
wheels with color being specified by individual RTA. Two spare
wheels per bus shall be provided.
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b. Tires shall be furnished by the SRTA, via its leased tire contractor at the time of
vehicle delivery. All low floor coaches shall be capable of using standard size
12R22.5 or equivalent mileage tires, except the 30 foot low floor which shall be
able to use 275/70R x 22.5.
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8.6 Air Suspension
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a. Coach shall be equipped with an air-suspension system. Air suspension system
shall consist of four (4) rear and four (4) front Rolling Lobe Firestone air bellows
and three (3) leveling valves as manufactured by Delco, or approved equal, by
which the air pressure is automatically regulated in proportion to the coach
loading. Leveling valve shall be installed in such a manner that will prevent
leveling valve roll-over.
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b. Air bellows shall act as a flexible connection between body and axle to absorb
and cushion road shocks.
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c. Leveling valves manufactured by Barksdale, or approved equal, shall also act
to keep the coach body in relatively level position and contain a dampening or
compensating feature to prevent excessive consumption of air resulting from
high-frequency axle movements over rough streets.
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d. Metal air chambers, if used, shall be guaranteed by the manufacturer for the life
of the coach. Methods of construction and the materials used shall be of such
manufacture as to permit easy and convenient replacement of bellows. Bellows
shall be mounted to provide easy replacement under coach.