A ramp’s grade determines its slope angle and the force pulling a loaded cart downhill. It does not, by itself, determine which caster brake will hold the cart. Calculate the whole-cart downhill force first, then compare that demand with documented holding performance for the exact caster, brake, loading arrangement, and floor conditions.
The tables below separate geometric conversion from brake selection. Their force values describe static holding demand—not the force required to stop a moving cart or an allowable ramp grade.
Convert Ramp Rise and Run to Grade and Angle
Measure vertical rise and horizontal run in the same units:
[
G = 100\frac{h}{L}
]
[
\theta = \tan^{-1}\left(\frac{G}{100}\right)
]
Where:
- (G) = ramp grade, expressed as a percentage.
- (h) = vertical rise, in inches, feet, or another length unit.
- (L) = horizontal run, in the same unit as rise.
- (\theta) = slope angle above horizontal, in degrees.
Horizontal run is not the distance measured along the ramp surface. For example, a 6-inch rise over a 120-inch horizontal run is a 5% grade, with an angle of approximately 2.86°. It is not a 5° slope.
Measure the section where the cart will actually stand. A route’s average grade can hide a steeper parking location. If the cart straddles a ramp transition or rests on a compound slope, a single longitudinal grade does not fully describe its support and stability conditions.
Ramp Grade, Angle, and Downhill Force Table
The following values are calculated for a straight, uniform incline. The force column uses a total loaded-cart weight of 1,000 lbf. It includes the cart, payload, fixtures, and accessories—not just the payload.
| Ramp grade | Rise over 120 in horizontal run | Slope angle | Downhill force for a 1,000 lbf loaded cart |
|---|---|---|---|
| 0% | 0.0 in | 0.00° | 0.0 lbf |
| 1% | 1.2 in | 0.57° | 10.0 lbf |
| 2% | 2.4 in | 1.15° | 20.0 lbf |
| 3% | 3.6 in | 1.72° | 30.0 lbf |
| 5% | 6.0 in | 2.86° | 49.9 lbf |
| 6% | 7.2 in | 3.43° | 59.9 lbf |
| 8% | 9.6 in | 4.57° | 79.7 lbf |
| 10% | 12.0 in | 5.71° | 99.5 lbf |
| 15% | 18.0 in | 8.53° | 148.3 lbf |
| 20% | 24.0 in | 11.31° | 196.1 lbf |
These are calculated reference values, not approved operating grades. Angles are rounded to two decimal places and forces to one decimal place; force calculations use unrounded values.
For another loaded weight, multiply the listed force by your total weight divided by 1,000 lbf. Use the formulas below when working from measured dimensions rather than a listed grade.
Calculate the Whole-Cart Holding Demand
For a stationary cart on a uniform incline, the component of its weight acting parallel to the ramp is:
[
F_{\parallel}=W\sin\theta
]
This is the standard resolution of gravity into components parallel and perpendicular to an inclined plane, as described in OpenStax’s Inclined Planes.
Substituting grade directly gives:
[
F_{\parallel}
=
W\frac{G/100}{\sqrt{1+(G/100)^2}}
]
Where:
- (F_{\parallel}) = downhill gravitational force, in lbf when (W) is in lbf.
- (W) = total loaded-cart weight as a force.
- (G) = grade percentage; enter 5 for a 5% grade.
Here, lbf means pounds-force. If a scale reports a loaded cart as 1,200 lb, its weight is approximately 1,200 lbf under standard gravity. Do not multiply an input already expressed in lbf by gravitational acceleration.
For an SI mass input:
[
F_{\parallel}=mg\sin\theta
]
Use mass (m) in kilograms and (g=9.80665\ \text{m/s}^2) to obtain force in newtons. Kilograms are mass, not holding force.
The result is the gravity-only holding demand for the whole cart. This calculation gives no credit for rolling resistance or incidental drag, and it adds no allowance for impacts, handling forces, brake deterioration, or manufacturer-required design margins. Those items require separate application data; there is no universal multiplier established by this table.
Example: A 1,200 lb Loaded Cart on a 5% Ramp
Assume the following hypothetical inputs:
- Empty cart and attached equipment: 300 lb.
- Payload: 900 lb.
- Total loaded weight: approximately 1,200 lbf under standard gravity.
- Ramp rise: 6 inches.
- Horizontal run: 120 inches.
- Cart stationary, with all supporting wheels on the same uniform incline.
- No external push, pull, or impact included.
Then:
[
G=100\frac{6}{120}=5%
]
[
\theta=\tan^{-1}(0.05)\approx2.8624^\circ
]
[
F_{\parallel}
=
1{,}200\frac{0.05}{\sqrt{1+0.05^2}}
\approx59.9\ \text{lbf}
]
The calculated downhill demand is approximately 59.9 lbf, or 266.6 N. That is the total force the holding arrangement must resist before any application-specific allowance.
Dividing by two gives approximately 30.0 lbf per brake only under an assumed equal contribution from two brakes. It does not establish that two brakes will actually share the demand equally. Caster position, wheel loading, brake engagement, frame deflection, and wheel-floor contact must support that assumption.
The Ramp Holding Force Calculator provides loaded-weight and grade inputs for this gravity calculation. Its result is a holding demand to investigate, not a brake rating.
Match the Brake Function to the Task
A wheel brake, total lock, and directional lock control different motions. “Total lock” describes the motions restrained; it does not mean unlimited holding force.
Blickle’s manufacturer documentation distinguishes wheel brakes, combined wheel-and-swivel locks, directional locks, and brakes intended to reduce speed while equipment is moving. Its directional locks fix caster orientation so the caster behaves like a fixed caster; they do not inherently stop wheel rotation.
| Device or function | Motion it restrains | Selection implication |
|---|---|---|
| Wheel brake | Wheel rotation; the swivel may remain free | A candidate for parking restraint, provided its documented holding performance and the complete arrangement meet the application. Do not assume it prevents cart repositioning through swivel movement. |
| Total lock | Wheel rotation and swivel rotation | A candidate when both rolling and swivel movement must be restrained. Confirm holding performance separately; the name does not provide a force rating. |
| Directional lock only | Swivel rotation at designated positions | Useful for directional tracking, but not a substitute for a wheel brake when downhill rolling must be restrained. |
| Brake intended for use while moving | Wheel rotation during travel, within its specified operating conditions | Required to evaluate controlled descent or stopping. A parking-lock rating alone does not establish this capability. |
The function distinctions above follow Blickle’s descriptions; allowable loads, grades, and holding forces still require documentation for the selected product.
A mechanically locked wheel can still slide across the floor. Mechanical engagement inside the caster does not eliminate the need for adequate wheel-floor traction. Static friction has a finite limit determined by the contacting surfaces and their normal load.
Use Manufacturer Ratings to Screen the Holding Arrangement
Compare downhill force with a holding rating—not a caster’s vertical load capacity. A caster advertised with a 500 lb load capacity has not thereby been shown to provide 500 lbf of ramp restraint.
For each candidate, obtain the exact caster model, wheel diameter and tread, brake option, and applicable installation or adjustment instructions. Then interpret the available data as follows.
| Available information | What it can establish | What remains necessary |
|---|---|---|
| Vertical caster load rating | Permitted supporting load under the manufacturer’s stated conditions | Separate brake holding data and confirmation of actual caster loads |
| Holding force per caster, in lbf or N | A force rating for the specified product and test conditions | Confirm force direction, wheel loading, surface, engagement, and whether it applies to one caster or an assembly |
| Holding torque, in lbf·in or N·m | Resistance to rotation at the stated component | Confirm the torque acts about the wheel axle and convert using the applicable rolling radius; evaluate floor slip separately |
| Maximum grade for a complete cart or system | A grade limit for the specified equipment configuration | Confirm total weight, center of gravity, caster layout, floor conditions, and operating mode match |
| “Wheel brake” or “total lock” with no performance data | The intended locking function | Obtain holding performance before making a numerical capacity comparison |
| Field holding measurement | Performance of the tested equipment in the recorded condition | Establish a controlled test method and determine how wear, contamination, load changes, and other conditions will be addressed |
If a manufacturer supplies wheel-axis holding torque (T), the corresponding tangential force is:
[
F=\frac{T}{r}
]
Use torque in lbf·in and effective wheel radius (r) in inches to obtain lbf, or N·m and meters to obtain N. This conversion represents resistance to wheel rotation. It does not establish the force at which the locked wheel will slide on the floor.
For preliminary force screening, the combined applicable holding capacity must at least balance (F_{\parallel}). Any required reserve must come from the manufacturer’s instructions or the equipment’s application assessment. Simply adding catalog ratings is insufficient unless the installed brakes can develop those forces together under the actual loading conditions.
Why Brake Count Alone Does Not Establish Capacity
Do not assign each braked caster the total cart weight divided by the number of casters unless the support arrangement justifies equal loading.
A lightly loaded braked wheel may contribute less floor restraint than a heavily loaded one. An uneven floor can unload a caster, and a shifted payload can change both wheel loading and stability. The arrangement must also resist unwanted rotation of the cart, not just straight downhill translation.
There is consequently no universal rule that two brakes, four brakes, or diagonally opposed brakes will hold every cart on a given grade. Brake locations and count must work with the actual support geometry, load distribution, and documented brake performance.
The Caster Brake and Lock Selector provides a preliminary comparison using cart weight, slope, caster count, and braked-caster count. Its published notes assume equal load sharing and describe a friction-based estimate. Treat its available-force and holding-ratio outputs as model estimates, not manufacturer ratings. A displayed “holds” verdict or the tool’s input range does not establish an allowable site grade.
Resolve Floor, Route, and Operating Conditions Before Relying on the Selection
A force calculation cannot establish whether the cart will remain stable, whether personnel can control it during travel, or whether the selected device is suitable for the parking location.
Keep those decisions tied to the actual equipment and route:
- Floor contact: Confirm the tread and surface conditions covered by the holding data. Water, oil, debris, coatings, and tread wear can change traction. Do not substitute a generic material-pair friction coefficient for applicable product or site evidence.
- Brake condition: Verify full engagement and the manufacturer’s adjustment and maintenance requirements. Blickle identifies adjustable holding pressure for several specific brake series and notes reduced brake forces with certain very soft treads, illustrating why brake performance must be checked for the exact configuration.
- Parking restraint: Where the operating procedure requires chocks or another restraint, select and position them for the wheel, grade, load, and surface. Do not count an unspecified chock as a known additional holding force.
- Route control: Define permitted parking locations, keep the potential downhill travel path clear, and arrange brake operation so personnel do not need to stand downhill of an unsecured cart.
- Stability: Evaluate center-of-gravity location, cross-slope, payload movement, and ramp transitions separately. Preventing wheel rotation does not prove that the cart cannot tip.
- Travel and stopping: If the cart must descend the ramp while moving, obtain braking data for the operating weight, speed, and duty cycle. Static holding force alone does not establish stopping distance, heat capacity, or operator control.
If applicable holding data are unavailable, the supported result is the calculated downhill demand—not a confirmed brake selection. Obtain product-specific information from the manufacturer or have the complete arrangement assessed through a controlled, restrained evaluation. Do not use an unrestrained loaded-cart trial on the ramp to discover whether the brakes hold.