Product Description
8 x 4 Wheel, EZ Compound
Specifications: 8.000 inch diameter x 4.000 inch width (8.000" x 4.000" | 8 x 4 wheel | 8 x 4 | 203.20mm x 101.60mm)
Specifications
Wheel Dimensions
| Outside Diameter | 8 |
| Inside Diameter | 2.25 |
| Width Side to Side | 4 |
| Bore Depth | 0.63 |
| Bore Outside Diameter | 2.4404 |
Frequently Asked Questions
Q: Is SU S684-A the same as SU S684 EZ-A?
A: No. SU S684-A is an EZ Compound wheel without the full assembly designation. Both are 8x4 with identical dimensions (203.20mm x 101.60mm, 2.25 inch bore ID). The difference is in how they are marketed or supplied: SU S684 EZ-A is typically sold as a complete assembly, while SU S684-A may be the wheel core only. Confirm with your supplier which includes bearings or caster hardware.
Q: Can I install the SU S684-A on a truck that originally had standard mold-on wheels?
A: Yes, if the original truck used 8x4 wheels with a 2.25 inch bore ID. The SU S684-A will fit the same axle shaft and caster fork. No frame modifications are required. However, if your original wheels had a different bore diameter (such as 2.5 inch or 2.75 inch), you cannot install this wheel without a new axle shaft, which requires bearing replacement.
Q: What are the dimensional specifications I need to verify before ordering the SU S684-A?
A: Verify: outside diameter (8 inches), width (4 inches), bore ID (2.25 inches), and bore outside diameter (2.4404 inches). These must match your existing axle shaft exactly. Measure the shaft OD with a caliper. If it differs by more than 0.05 inch, the wheel will not fit properly. Also confirm the bore depth of 0.63 inches matches your axle length and bearing configuration.
Q: How do I diagnose if the SU S684-A wheel is wearing prematurely?
A: Signs of premature wear include flat spots larger than 1/8 inch, chunking or torn rubber, sidewall cracking, or uneven wear patterns across the width. Uneven wear often indicates bearing misalignment or a worn caster swivel joint. If only one or two wheels show excessive wear and others are fine, the problem is caster geometry or alignment, not the wheel itself. Address the root cause before replacing.
Q: What maintenance extends the life of the SU S684-A wheel?
A: Clean wheels weekly to remove debris that embeds and tears the rubber. Inspect bearings monthly for free play by hand-spinning the wheel; if it feels rough or wobbles, repack or replace bearings. Ensure casters are properly aligned during installation to prevent toe-in wear. Store replacement wheels indoors away from direct sunlight and ozone sources, which degrade rubber. These practices add 6-12 months to wheel lifespan.