Match the calculation to the operating condition—not just the equipment name. An AGV needs a load-distribution check under acceleration and braking. A replacement cart wheel needs a dimensional fit check. A parked machine on leveling pads needs a support-load and contact-pressure estimate. None of those results answers the other questions.
The first distinction is the object being evaluated: a wheel, a complete caster assembly, or the loaded equipment. A wheel’s rating does not establish the capacity of its fork, swivel head, mounting hardware, or supporting frame. Likewise, a dimensional match does not establish load capacity, braking performance, or suitability for the floor.
Choose the Calculation by the Decision You Need to Make
| Application or operating condition | Start with | What the result helps you evaluate | What remains to be confirmed |
|---|---|---|---|
| AGV or AMR with drive wheels and support casters | AGV and AMR Caster Load Calculator | Estimated loads on drive wheels and support casters | Actual support reactions, component ratings, traction, and vehicle dynamics |
| Office chair caster replacement | Office Chair Caster Replacement Matcher | Dimensional and floor-selection prompts | Stem retention, socket fit, chair approval, and complete caster capacity |
| Shopping cart, luggage trolley, or stock cart wheel replacement | Shopping Cart Wheel Matcher | Wheel diameter, tread width, hub length, and axle-bore comparison | Bearing installation, fork clearance, load rating, and tread suitability |
| Machine or workbench parked on leveling pads | Leveling Caster Pad Pressure Calculator | Equal-share pad load and nominal pad pressure | Unequal support reactions, pad limits, and floor construction |
| Multiple carts pulled as a train | Caster Train Towing Force Calculator | Steady towing-force scenarios | Starting peaks, turning behavior, coupler loads, braking, and tug traction |
| Loaded cart parked on a ramp | Ramp Holding Force Calculator | The downhill component of the cart’s weight | Brake or restraint capacity, wheel-floor traction, and stability |
| Hospital, instrument, warehouse, or facility cart on a sensitive floor | Caster Floor Protection Assessment | A qualitative floor-risk screening | Actual tread performance, coating compatibility, and contact conditions |
These tools provide estimates or matching prompts, not product approvals. Use them to identify the next measurement, compare a proposed change, or prepare a supplier inquiry.
Establish the Load and Operating Condition First
Record the equipment’s empty weight and its maximum intended payload, including batteries, fixtures, containers, and accessories. Then distinguish three conditions:
- Parked: the equipment is stationary, possibly supported on pads rather than wheels.
- Manually moved: starting, rolling, steering, stopping, and obstacle crossing create different demands.
- Powered or towed: travel speed, acceleration, braking, route conditions, and duty cycle must match the selected components.
For moving equipment, compare the estimated service loads with the complete caster’s applicable dynamic rating—not simply a wheel’s static rating. Blickle’s load-capacity guidance distinguishes static and dynamic capacity and notes that individual loads can differ when equipment has four or more supports. Its application factors address departures from its stated reference conditions; they are not universal factors for every caster or vehicle.
Dividing total loaded weight by the number of wheels gives an average, not necessarily the highest wheel load. Uneven floors, frame stiffness, suspension, and an offset center of gravity can change the reactions. Counting “all wheels minus one” may be a useful assumption for a particular design, but it does not resolve those effects automatically.
Where load distribution controls the decision, obtain support reactions from the equipment manufacturer, a suitable engineering model, or controlled measurements using appropriately rated weighing equipment. Evaluate the relevant payload positions rather than only the centered-load condition.
AGVs and AMRs: Separate Support Loads From Drive-Wheel Requirements
The AGV and AMR Caster Load Calculator presents static and worst-case per-caster loads, a worst-case drive-wheel load, and an axle comparison. Its page describes a preliminary load-splitting model with acceleration and braking effects; it excludes lateral transfer during cornering, suspension compliance, and transient pitch behavior.
Prepare the following information before using a load estimate:
- Robot weight without payload and maximum payload weight.
- Number and arrangement of drive wheels and support casters.
- Longitudinal center-of-gravity location for the robot and payload.
- Combined center-of-gravity height and wheelbase.
- Relevant acceleration and braking cases.
- Dynamic ratings for the exact drive-wheel and caster configurations.
For a simplified rigid vehicle supported on two axle groups on level ground, the magnitude of longitudinal load transfer is:
[
\Delta R = W\frac{a}{g}\frac{h}{L}
]
Here, (\Delta R) is the load transferred between axle groups in lbf, (W) is total loaded weight in lbf, (a/g) is acceleration expressed as a fraction of gravitational acceleration, and (h) and (L) are center-of-gravity height and wheelbase in the same length unit. The expression assumes a quasi-static longitudinal model without suspension or transient pitch effects.
The transfer increases one group’s reaction and decreases the other’s. Dividing an axle-group reaction by its wheel count additionally assumes equal sharing within that group. A support caster mounted on a compliant mechanism may not follow that assumption.
Do not interpret the axle with the larger calculated per-wheel load as automatically setting the payload limit. That requires comparing each group’s demand with its own applicable capacity. Drive-wheel traction and braking must also be checked separately: a wheel can remain below its load rating while carrying too little normal force to transmit the required drive or braking force.
If the available tool inputs do not represent your wheelbase, center of gravity, or support arrangement, use a separate load-transfer analysis rather than treating the displayed result as vehicle-specific.
Office Chairs: Match the Attachment Before Choosing the Tread
The Office Chair Caster Replacement Matcher provides dimensional and floor-selection prompts. It is not a parts database, does not measure thread pitch, and does not compare a proposed replacement’s wheel diameter against the original. Its output therefore cannot confirm that a specific replacement fits the chair.
Start with the chair manufacturer’s replacement specification. If measurement is necessary, identify the attachment type before recording dimensions:
- Grip-ring or other push-in stem: stem diameter, insertion length, retention feature, and socket condition.
- Threaded stem: thread diameter, pitch, usable engagement length, and seating arrangement.
- Other attachment: the complete mounting geometry and retention method specified for the chair.
Do not confuse the wheel’s axle bore with the stem that attaches the caster to the chair base. They are different interfaces.
Compare overall mounting height as well as wheel diameter. Different caster forks can produce different chair heights even when the wheels have the same diameter. Check swivel clearance, interference with the base, and any original braking or load-activated rolling function.
Choose a tread approved for the actual floor or carpet, then confirm the complete caster and chair weight limits. A matcher’s “light-duty” or dimensional classification is not a capacity approval. User weight alone omits the chair’s own weight and does not establish the distribution or transient loading of the caster set.
Shopping and Stock Carts: Distinguish a Wheel Replacement From a Caster Replacement
The Shopping Cart Wheel Matcher uses wheel diameter, tread width, hub length, axle bore, and bearing information to organize a replacement search. Its size classes are generic; it does not establish a part number or evaluate load rating and tread compound.
For a wheel-only replacement, record:
- Wheel diameter across an unworn portion of the tread, or the original nominal diameter.
- Tread width.
- Hub length across the faces that locate the wheel between the fork legs.
- Axle diameter and the bearing, bushing, or sleeve arrangement.
- Spacers, seals, and hardware that control wheel position and bearing clamping.
Check the replacement assembly against the fork’s inside width and available radial clearance. The wheel must rotate freely after the axle hardware is tightened as specified. A matching bore alone does not show that the bearing stack will clamp correctly.
For a complete caster replacement, also compare the mounting interface, overall height, swivel offset, swept clearance, and brake-pedal clearance. Top-plate outside dimensions are not the same measurement as bolt-hole spacing.
Retain the cart manufacturer’s required wheel and caster capacities even for retail shopping carts. A familiar size or apparently light application does not remove the need for a load-rating check. Where dimensions differ, obtain a supplier-approved bearing or spacer arrangement rather than assuming a loose bore can simply be adapted.
Warehouse Platform Carts: Check Steering and Push Effort Together
A platform cart can meet its caster load requirement and still be difficult to operate. Starting from rest, rolling straight, reversing swivel casters, turning in an aisle, and crossing a joint are separate events.
Blickle’s resistance guidance distinguishes starting, rolling, and swivel resistance. It identifies wheel diameter, tread properties, bearings, surface conditions, and caster offset as relevant factors. Its published rolling-resistance comparisons use controlled test conditions, so they should not be treated as measurements of your warehouse route.
For an existing cart, use a suitable force gauge at the normal handle position to record starting and sustained forces separately. Include the unfavorable initial caster orientation and the route’s difficult turns and joints. Record loaded weight, floor condition, travel speed, and wheel condition so that comparisons remain meaningful.
Caster layout also matters. Compare straight-line tracking and lateral maneuverability in the actual aisle geometry; a layout that turns easily in open space may behave differently when entering a narrow workstation.
Do not convert a single measured or calculated force into an ergonomic pass/fail decision. CCOHS handcart guidance treats force, travel distance, duration, repetition, handle arrangement, floor conditions, and operator factors as parts of the task assessment.
Cart Trains: Estimate Steady Pull Before Checking Peaks and Braking
The Caster Train Towing Force Calculator accepts cart count, loaded weight per cart, caster count, rolling resistance, swivel and coupler allowances, route grade, and available drawbar pull. It reports steady pull and its share of the entered available pull. The model assumes identical, freely rolling carts and excludes startup and slack-take-up transients.
For a basic uphill, constant-speed comparison:
[
F_{\text{steady}} \approx C_{\text{rr}}W\cos\theta + W\sin\theta
]
Here, (F_{\text{steady}}) is pull parallel to the route in lbf, (W) is the train’s total weight in lbf, (C_{\text{rr}}) is a dimensionless effective rolling-resistance coefficient, and (\theta) is the incline angle. This simplified expression does not include turning, acceleration, caster realignment, or coupler effects.
Confirm the resistance parameter’s definition before entering it. A rolling-resistance parameter expressed in inches or millimeters is not a dimensionless coefficient and cannot be substituted directly.
Use fleet measurements or applicable supplier data for allowances. The calculator’s swivel and coupler factors are scenario inputs, not universal physical constants. Do not add them to an effective resistance measurement that already includes the same losses.
A drawbar-pull comparison does not establish permissible train length, coupling capacity, stopping distance, or cornering behavior. Confirm those with the tug and cart suppliers for the intended speed, route, and duty. A steady uphill calculation also does not establish downhill control.
Machines on Leveling Casters: Evaluate the Parked and Moving States Separately
Leveling casters have distinct operating states. For example, FOOT MASTER’s leveling-caster instructions describe lowering the pad to hold equipment in position and raising it for movement. Confirm the exact model’s operating instructions and applicable ratings in both states.
The Leveling Caster Pad Pressure Calculator estimates load per pad and nominal pad pressure from total parked weight, support count, and pad diameter. Its stated assumptions include even load sharing and a flat, rigid floor.
For (n) equally loaded, fully contacting circular pads:
[
R=\frac{W}{n}
\qquad
A=\frac{\pi d^2}{4}
\qquad
p=\frac{R}{A}
]
Here, (W) is parked weight in lbf, (R) is load per pad in lbf, (d) is pad diameter in inches, (A) is nominal contact area in square inches, and (p) is average pressure in psi.
As a hypothetical example, a 1,200 lbf machine supported equally by four flat, fully contacting 2-inch-diameter pads produces:
- Load per pad: (1{,}200/4=300) lbf.
- Nominal area per pad: (\pi(2)^2/4=3.142) in².
- Average pressure: (300/3.142\approx95.5) psi.
These are nominal geometric values, not measured contact pressures. Pad deformation, incomplete contact, and unequal reactions can change the local pressure.
Do not compare this psi value directly with a floor’s uniform-load rating in psf. A finish’s indentation limit, a raised-floor panel’s concentrated-load capacity, and a slab’s structural capacity describe different failure modes. Obtain the relevant floor information and review requirements before relying on the pad arrangement.
Ramps: Calculate the Gravity Demand, Then Verify the Restraint
The Ramp Holding Force Calculator calculates the component of loaded cart weight acting downhill. It does not calculate stopping distance or establish the capacity of a particular brake.
For a stationary cart:
[
F_{\text{downhill}}=W\sin\theta
]
If ramp grade (G) is entered as a percentage:
[
\theta=\arctan\left(\frac{G}{100}\right)
]
Here, (W) is loaded cart weight in lbf, (F_{\text{downhill}}) is force parallel to the ramp in lbf, and grade is rise divided by horizontal run, multiplied by 100. A 5% grade is not a 5-degree incline.
For a hypothetical 1,000 lbf cart on a 5% grade:
[
F_{\text{downhill}}
=1{,}000\sin\left[\arctan(0.05)\right]
\approx49.9\text{ lbf}
]
That is the gravity demand before applying any manufacturer-required holding margin. It is not a brake rating.
Verify the restraint’s published holding performance, installation, and use conditions. A wheel brake, swivel lock, and total-lock caster perform different functions; their names alone do not establish slope-holding capacity. A locked wheel may still slide, and holding a stationary cart is different from stopping a moving one. Do not use a person’s ability to resist the calculated force as the parking method.
Hospital and Instrument Carts: Treat Floor Protection as a Contact-System Decision
The Caster Floor Protection Assessment returns a qualitative risk band and selection prompts. It does not calculate contact pressure, and its published limitations state that wheel diameter is not included in the score itself. The score is therefore a way to prioritize investigation, not a prediction of damage or a validated minimum wheel size.
Evaluate the actual combination of wheel load, tread compound, floor finish, contamination, and turning behavior. “Non-marking” does not establish that a wheel will avoid indentation, abrasion, or damage from trapped debris.
Blickle’s floor-preservation guidance relates average contact pressure to wheel force divided by contact area and describes the general noise and cushioning benefits of larger wheels with soft, thick treads. It also shows that rolling behavior depends on more than hardness alone. These relationships help form a shortlist; they do not approve a tread for a particular coating or cleaning chemical.
For hospital and instrument carts, compare candidates under the intended loaded condition for noise at joints, vibration transmission, steering effort, and floor marking. Obtain compatibility information for the actual tread, seals, bearings, and cleaning agents. If electrical resistance or other specialized performance is required, use a specifically documented configuration rather than inferring performance from the tread material name.
Turn the Result Into a Replacement or Purchase Specification
A useful calculation should lead to a specification that a supplier can evaluate. Include:
- Whether the request is for a wheel, complete caster, or leveling-caster assembly.
- Equipment weight, payload range, and the basis for the maximum support reaction.
- Manual or powered operation, travel speed, route conditions, and duty cycle.
- A dimensioned mounting and clearance record.
- Floor finish, contamination, cleaning chemicals, and temperature exposure.
- Required braking, locking, bearing, and retention features.
If an existing assembly has failed, document the failure before selecting a higher rating. Record tread damage, bearing play, fork distortion, loose mounting hardware, and where on the route the problem occurs. Those observations help distinguish overload from impact, binding, contamination, or installation problems.
Compare purchase options on the same basis: per wheel versus per caster, quantity required, installation hardware, labor, and any known downtime. Treat service life as unknown unless relevant operating and maintenance records support an estimate. A lower calculated load, a softer tread, or a higher catalog rating alone does not establish a longer replacement interval.