Trucks Rim
For truck tyres, there are essentially 3 basic rim types available on the market:
a. one-piece tubeless drop centre rims
b. multi-piece tube-type flat base rims
c. multi-piece tubeless flat base rims
I-PIECE TUBELESS DROP CENTRE
50 DROP CENTRE RIM
(13", 14", 17" ETC ... ) symmetric and asymmetric rims for standard and low section light truck (C) tyres.
15 DEGREE DROP CENTRE RIM
(17.5",19.5",22.5" etc ... ) rims for standard and wide section (Low Aspect Ratio, Super Single) tyres.
2- AND 4-PIECE TUBE-TYPE FIAT BASE
(mainly 20") rims for high aspect ratio tyres. It will be important to avoid interchanging of parts from both systems. Note that each system is usually identified accordingly (stamped 2P or 4P)
2-PIECE TUBE-TYPE FIAT BASE
4-PIECE TUBE-TYPE FIAT BASE
4-PIECE TUBELESS FLAT BASE
(20") rims for mainly 80-series tyres. They require a new sealing gasket for each new tyre.
- Drop centre
- Disc
- Rim/disc junction
- Hub contact face
- Pitch (bolt) circle diameter
- Offset
- Centre hole diameter
- Stud hole diameter
- Rim flange
- Taper
- Rim Width
- Rim flange height
- Rim flange width
- Rim flange radius
- Valve hole
- Ball tape
NOTE: Rim diameters can only beaccuratelymeasuredby means ofa specialball tape.
All wheels have a given offset (0) which does not only provide for the necessary brake drum space, but which also determines track width, kingpin offset, handling characteristics and wheel bearing load. On dual assemblies, it also influences the dual spacing.
Tyre fitters and mechanics must therefore pay attention that:
a. specific vehicles are fitted with the correct offset wheels.
b. wheels with different offsets are not mixed up on the same axle.
Wheel offsets can be positive, negative or zero. The offset is defined as the distance from the wheel centre to the inside face of the disc (against the hub) and is called positive whenever this inside face is located outside of the centreline, negative when located inside, zero when matching the centreline exactly.