Ramps, loading and breakover
Ramps and loading come down to ramp angle, which is trigonometry from two measurements.
Loading
Loading is where the injuries happen, and the two variables that decide how dangerous it is are ramp angle and ramp capacity. Ramp angle is simple trigonometry. The sine of the angle is the deck height divided by the ramp length, so a two-foot deck with a six-foot ramp gives about nineteen degrees, and the same deck with an eight-foot ramp gives about fourteen.
A lower calculated angle does not establish a safe loading angle for every machine. Check the machine and ramp manufacturers’ loading instructions and the rating of each ramp or pair.
Secure the ramps as their manufacturer specifies and keep bystanders clear. Use only a loading method approved for the machine and ramp; do not assume that riding up a ramp is permitted.
Ramp angle, from two measurements
You need the deck height at the loading edge and the usable ramp length. Measure both. Do not assume them.
Trailer deck heights vary by several inches between models, and a loaded trailer sits lower than an empty one.
| Deck height | 6 ft ramp | 8 ft ramp | 10 ft ramp |
|---|---|---|---|
| 18 in | 14.5° | 10.8° | 8.6° |
| 24 in | 19.5° | 14.5° | 11.5° |
| 30 in | 24.6° | 18.2° | 14.5° |
| 36 in | 30.0° | 22.0° | 17.5° |
| 42 in (pickup bed) | 35.7° | 25.9° | 20.5° |
Both values are geometric, calculated from the two dimensions, so they are exact for the measurements given. The numbers do not say whether a specific machine will clear the transition at the top. Wheelbase, ground clearance and the shape of the ramp decide that.
Breakover: the problem the angle number hides
A long, low machine can be stopped by the transition where the ramp meets the deck even when the angle is modest, because the middle of the machine grounds while both ends are still supported. Breakover is the name for that. It is a function of wheelbase and ground clearance, not ramp angle.
A ramp with an arch or a bend near the top exists specifically to reduce it, by flattening the transition. Where that is not available, loading from a bank or a slope so the trailer sits lower relative to the ground is the practical fix, and it is the reason experienced people load in the same spot every time.
Ramp capacity, and the per-ramp trap
Ramps carry a load rating, and it is commonly stated for a pair instead of for one ramp, or the reverse. A pair rated at 1,500 pounds total is not two ramps each carrying 1,500. Reading it the wrong way round is an easy mistake, and the result is a genuine overload, because the entire machine weight passes through the ramps during loading.
Each tire needs adequate support throughout the loading path. For separate ramps, check their individual width, spacing and attachment against the machine’s wheel track; a single ramp’s width is not the machine’s total track width.
For a side-by-side, a full-width ramp or a pair spaced accurately to the track is worth the difference in cost.
The practices that prevent the injuries
- Secure the ramp to the trailer. Most ramps have a strap or a pin for exactly this. An unsecured ramp can kick backwards under load, which drops the machine and whoever is behind it.
- Never stand behind or below. If the machine comes back down, that is where it goes. Stand to the side, and if you are walking a machine up, be beside it, not behind it.
- Ride or winch and not push. Pushing a heavy machine up a ramp puts you in the worst possible place and gives you no way to stop it. A winch on the trailer front is the answer for anything you cannot comfortably ride.
- Load on level ground. A trailer on a camber twists the geometry and a machine loaded across a slope is much easier to drop.
- Chock the trailer wheels. A trailer that rolls while a machine is on the ramp turns a controlled process into an uncontrolled one instantly.
Unloading is more dangerous than loading. Gravity is now working with the machine instead of against it. The ramp is behind you where you cannot see it.
Back down slowly with the machine under power or under brake. Keep a straight line. If you are not confident on a particular ramp angle, do not attempt it.
A longer ramp is a cheaper solution than the alternative.
References
- Federal rule Cargo Securement Rules: driver and carrier guidance: Federal Motor Carrier Safety Administration.
- Federal rule Protection Against Shifting and Falling Cargo: general securement rules: U.S. Government Publishing Office (eCFR), 49 CFR §§ 393.100–393.114.
Loading
Loading is where the injuries happen, and the two variables that decide how dangerous it is are ramp angle and ramp capacity. Ramp angle is simple trigonometry. The sine of the angle is the deck height divided by the ramp length, so a two-foot deck with a six-foot ramp gives about nineteen degrees, and the same deck with an eight-foot ramp gives about fourteen.
Five degrees is the difference between a machine that walks up and one whose front wheel wants to lift. Ramp capacity is a rating in pounds. The important detail is whether it is stated per ramp or for a pair. Misreading that is a common way to end up accidentally over. The practices that prevent injuries are not complicated.
Never stand behind or below a machine on a ramp, secure the ramp to the trailer so it cannot kick out, and ride or walk a machine up instead of pushing it from below.
Ramp angle, from two measurements
You need the deck height at the loading edge and the usable ramp length. Measure both. Do not assume them. Trailer deck heights vary by several inches between models, and a loaded trailer sits lower than an empty one. The angle in degrees is the inverse sine of deck height divided by ramp length.
Ramps and loading questions
How do I calculate ramp angle?
The sine of the angle equals the deck height divided by the ramp length, so the angle is the inverse sine of that ratio: a 24-inch deck with an eight-foot ramp gives 24 ÷ 96, or 0.25. The angle is about 14.5 degrees. Measure both dimensions, not assuming them, because a loaded trailer sits lower than an empty one.
What ramp angle is too steep?
Ramp makers advise 15 degrees or less. At 15 degrees a 24-inch deck needs a ramp of about 7.7 feet (24 inches divided by the sine of 15 degrees, 0.2588, is 92.7 inches), and a 36-inch deck about 11.6 feet. Above 15 degrees the front wheel wants to lift and a long wheelbase or low ground clearance drags at the top, so a machine that does either needs a longer ramp.
Most loading incidents involve short ramps on high decks.
What is breakover and why does it matter?
Breakover is the machine grounding in the middle at the transition where the ramp meets the deck, while both ends are still supported. Breakover is a function of wheelbase and ground clearance, not of ramp angle. A long, low machine can hang up on a perfectly gentle ramp. Arched ramps exist specifically to reduce it.
Is a ramp rating per ramp or per pair?
The rating varies by manufacturer, and reading it the wrong way round is an easy and genuine overload. A pair rated at 1,500 pounds total is not two ramps each rated 1,500. Check the wording on the product, not assuming, because the whole machine weight passes through the ramps during loading.
Should I ride the machine up or push it?
Ride it, or winch it. Pushing puts you directly behind and below the machine, exactly where it goes if it comes back down. You have no way to stop it. A winch mounted at the front of the trailer is the right answer for anything heavy enough that riding it up feels marginal.
How do I stop a ramp kicking out?
Secure it to the trailer using the strap, pin or hook the ramp provides: most have one, and most people do not use it. An unsecured ramp can slide backwards under load, dropping the machine and anyone behind it. Securing the ramp is a ten-second step that removes one of the two common loading failures.
How wide should a ramp be for a side by side?
Wide enough that a wheel drifting a few inches does not run off the edge. For a side-by-side that generally means a full-width ramp or a matched pair accurately spaced to the machine’s track. A ramp only just wider than the tire leaves no margin. Halfway up is not the time to discover that.
Is unloading more dangerous than loading?
Yes. Gravity is working with the machine, not against it. The ramp is behind you where you cannot see it. Any correction happens faster. Back down slowly and straight with the machine under control. Treat a ramp angle you are not confident reversing down as one you should not have loaded from.
Do I need to chock the trailer wheels?
Yes, and it costs nothing. A trailer that rolls while a machine is partway up a ramp turns a controlled operation into an uncontrolled one instantly, and the tow vehicle’s parking brake is not always enough on a slope with the coupling loaded and unloaded in turn.
Can I load from a bank or a ditch instead?
Loading where the ground is higher relative to the trailer reduces the effective deck height and therefore the ramp angle, and experienced people load from the same spot every time for exactly that reason. The requirement is that the trailer is level side to side and secure, because a trailer on a camber makes everything harder.
What is the safest ramp material?
The rating matters more than the material. Aluminium ramps are light enough to handle easily, so they get used and secured properly. Steel is heavier and often cheaper. Wooden planks have no rating at all and no way to know how much strength age and weather have taken out of them.
Should I have someone spot me?
A second person is useful. Standing well clear and to the side, they watch for the wheel drifting off a ramp, ready to be a pair of hands after the machine is up. What they must not do is stand behind or below the machine to steady it. Most loading injuries involve a helper in exactly that position.
- Tie-down rules for once it is up there
- The count test and the aggregate rating test, both federal.
- GVWR, GCWR, payload and tongue weight
- Whether the machine should be on that trailer at all.
Trailer load match calculator; Ratings, tongue weight and the payload it takes out of the truck.
- UTV ownership: why a side-by-side needs more ramp
- Weight, width and wheelbase all work against you at once.