SU 124

Frequently Asked Questions

Q: What is the SU 124 load wheel used for and what lift truck models does it fit?
A: The SU 124 is a 3.25-inch diameter x 2.75-inch width load wheel (swivel wheel or steer wheel) made of Cushothane and used on electric pallet jacks, walk-behind lift trucks, and some narrow-aisle reach trucks. It is typically installed on the steering axle or load-carrying axle. The equivalent part is the SU 124-A (which includes a machined steel hub core). Cross-check your truck OEM manual for the correct wheel bore diameter and hub configuration. The SU 124 is smaller than main drive wheels and handles 25 to 40 percent of the truck load depending on axle geometry. Do not confuse with drive wheel sizes.

Q: How do I diagnose failure of the SU 124 load wheel and what are typical symptoms?
A: Common failure symptoms: the truck pulls or drifts to one side during operation, the wheel feels loose or wobbles when you spin it by hand, you hear grinding or squeaking sounds, or the Cushothane tread is flat-spotted or cracked. Check bearing play by lifting the truck and checking if the wheel has side-to-side movement (should be minimal). If the wheel cannot be centered or keeps tilting, the hub bore or bearing may be damaged and the entire wheel assembly needs replacement. Cushothane is prone to compression set (permanent deformation) under sustained load; if the wheel no longer rolls smoothly after sitting loaded for days, tread hardening has occurred and replacement is necessary.

Q: What is the load capacity and operating specification for the SU 124?
A: The SU 124 is rated for 150 to 250 pounds per wheel depending on whether it is installed as a single steering wheel or a pair of load wheels. Maximum recommended load per axle is 1,000 to 1,500 pounds. The wheel hub has a 1.9375-inch inside diameter and 2.0475-inch bore outer diameter with a 0.822-inch bore depth. Do not exceed manufacturer rated load or the Cushothane will compress permanently, creating safety and handling issues. Operating speed should not exceed 4 mph on smooth floors. The wheel is designed for indoor warehouse use and does not perform well on rough concrete or outdoors due to Cushothane compound degradation.

Q: Can I replace the SU 124 with the SU 124-A, or are they interchangeable?
A: The SU 124-A is an upgraded version with a machined steel hub core and pre-installed shoulder bearings versus the standard SU 124. If your truck specifies the SU 124, you can upgrade to the SU 124-A as a direct replacement; the mounting configuration and dimensions are identical. The SU 124-A offers improved durability and longer service life (36 to 48 months versus 24 to 36 months for the SU 124). However, if your truck specifies SU 124-A, do not downgrade to the SU 124 as bearing capacity and mounting interference differ. Verify the OEM part number on your existing wheel to confirm which version is correct.

Q: What maintenance and storage practices extend SU 124 wheel life?
A: Inspect the wheel monthly for cracks, flat spots, or hardening of the Cushothane tread. Clean debris from the wheel and hub area to prevent bearing contamination. Do not over-lubricate the hub bore; excess grease attracts dirt. Check that the wheel spins freely without binding; if it does not, the bearing may be damaged or contaminated. Rotate the truck daily when parked to prevent permanent compression set from sustained load on one wheel. Store spare wheels indoors away from heat and direct sunlight; Cushothane hardens and loses elasticity in UV exposure. Avoid stacking wheels directly on the Cushothane tread as this causes permanent deformation. Expected service life is 24 to 48 months depending on floor condition and daily use hours.