| Mount Type | Load Range | Install Tools | Typical Use | Re-install |
|---|---|---|---|---|
| Plate (4-bolt) Most Common | 75–20,000 lb | Drill + bolts + wrench | Industrial, OEM, dollies | Easy |
| Threaded Stem | 75–1,400 lb | Wrench + Loctite | Office, institutional, OEM | Easy |
| Grip Ring Stem | 40–250 lb | Soft mallet | Office chairs, retail fixtures | Easy |
| Expanding Adapter | 75–500 lb | Hex key | Tubular legs, furniture | Easy |
Each mount type in detail. Load class, install method, when to spec.
A flat rectangular steel plate with 4 bolt holes, bolted directly to a flat cart surface. The industrial standard for any application above 1,200 lb per caster. Capacity ranges from 200 lb on light-duty 2-1/2 x 3-5/8 plates up to 40,000 lb on extra-heavy 8 x 10 plates.
Most forgiving mount type. If your bolt pattern matches, the caster will work. Common plate sizes: 2-3/8 x 3-5/8 (light), 4 x 4-1/2 (medium-duty default), 4-1/2 x 6-1/4 (heavy), 6-1/2 x 7-1/2 (extra-heavy), 8 x 10 (industrial extreme). Spec the plate first, then the wheel.
A threaded bolt protruding from the top of the caster, screwed into a threaded socket or insert. Common thread sizes: 3/8-16, 1/2-13, 5/8-11, 3/4-10. The stem becomes the structural connection, so it is the failure point. Capacity tops out around 1,200 lb per caster because the stem will pull out before the wheel fails.
Use for tube-frame carts, scaffold, racks, retail fixtures, and any application where the receptacle is a threaded insert. Faster to install than plate. Three common gotchas: cross-threading on first install, vibration loosening over time (use Loctite or a nylon-insert lock nut), and corrosion welding the stem into the socket after years of service.
A smooth stem with a spring-loaded retaining ring (grip ring) that snaps into a corresponding groove in the receptacle. Common stem diameters: 7/16, 1/2, 5/8. Capacity 75 to 500 lb per caster. The fastest mount to install: push and click.
Standard for chairs, hospital beds, light service carts, and any application where the receptacle has an internal groove. Failure mode is grip ring fatigue: after 10,000+ insert/remove cycles the ring loses tension and the stem pulls out. Replace the caster, not just the ring.
A stem with a tapered rubber expansion sleeve that compresses inside the cart tube as the central bolt is tightened. The sleeve grips the inside of the tube. Common ID sizes: 1-inch, 1-1/16, 1-1/8 (round tubes); square tubes available. Capacity 200 to 800 lb per caster.
The right mount for retrofitting casters into tube-frame carts that have no factory bracket or threaded socket. The sleeve self-centers and adjusts to slight tube ID variations. Failure mode is sleeve degradation in chemical or hot environments. Replace every 5 years on hard-use carts.
A through-hole in the top of the caster yoke. Mounts with a single bolt passing through the hole into the cart frame. No top plate, no protruding stem. Capacity tied to bolt size: a 1/2-inch through-bolt handles 1,000-1,500 lb, a 5/8-inch through-bolt handles 2,500 lb.
Low-profile mount for height-constrained applications. Common on tilt-truck, drum-handling, and any cart where a top plate would interfere with cart bed. Requires precise bolt-hole alignment and proper torque. Pair with a lock washer or thread locker.
| Plate Size (L x W) | Bolt Hole Pattern | Bolt Size | Capacity Range | Common Use |
|---|---|---|---|---|
| 2-3/8 x 3-5/8 | 1-3/4 x 2-3/4 | 5/16 | 200-500 lb | Light cart, fixture |
| 3-1/8 x 4-1/8 | 2-7/16 x 3-3/8 | 3/8 | 300-900 lb | Medium service cart |
| 4 x 4-1/2 | 2-5/8 x 3-5/8 | 3/8 | 500-2,000 lb | Industrial default |
| 4-1/2 x 6-1/4 | 2-7/16 x 4-15/16 | 1/2 | 1,200-4,000 lb | Heavy duty cart |
| 5 x 6-1/4 | 3 x 4-1/2 | 1/2 | 2,500-5,000 lb | Heavy industrial, tow |
| 6-1/2 x 7-1/2 | 4-1/2 x 6 | 5/8 | 5,000-12,000 lb | Extra heavy, dock plate |
| 8 x 10 | 5-1/2 x 7-1/2 | 3/4 | 10,000-40,000 lb | Aerospace tooling, dies |
To replace casters on an existing cart, measure these four dimensions before ordering.
For threaded stem retrofits: measure stem diameter, thread pitch (TPI), and stem length. Use a thread gauge if available, otherwise count threads per inch with a ruler.
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