Loading a car up a ramp without bending it or scraping the belly

A 22-inch trailer deck and a friend’s low coupe are how most people find out that “long enough” is not a measurement. You lean the aluminum ramps against the deck, they look about right, you drive up, and either the front lip catches the bumper or the belly drags at the exact spot where the ramp meets the ground. Rampset turns that guess into two numbers you can read off a phone before the vehicle moves. This page runs both of them through a real load and says plainly where the math stops being something you can lean on.

A 22-inch deck and a car that keeps scraping

Start in the default Ramp Length mode. Enter a deck height of 22 in, tap the “Car” preset so the angle field fills with a value in the 10 to 15 degree band, and set it to 12 degrees. The tool solves the required length live, with no submit button:

That is the minimum straight ramp for a 12-degree approach. Own a ramp shorter than that and you’re steeper than 12 degrees whether you meant to be or not. Now flip to Ramp Angle mode and enter a ramp you already have. A 72-in (6 ft) ramp under the same 22-in deck reverse-solves to:

Eighteen degrees is well past the car band and into scraped-splitter territory. Same deck, same ramp, and the single number that decides the outcome was the one nobody measured.

Why the load-type preset changes the answer

Every vendor calculator we surveyed, 13 of them, defaults to a single 1:12 slope, roughly 4.76 degrees. That figure comes from the ANSI A117.1 accessibility code for wheelchair ramps, not from loading a vehicle, and it produces ramps far longer than a mower or UTV will ever need. Rampset drops the one-size slope for load-type presets you can still type over:

A riding mower tolerates a steeper climb than a sports car because it has nothing hanging low off the nose to catch. Pick the load, take the sensible default, override it when you know your own gear.

The second number nobody else puts up front

Here is the input the length-only tools skip. A long enough ramp fixes the approach angle and still lets a low car high-center at the transition, the hinge where the ramp meets the ground. So Rampset asks for ground clearance G and wheelbase WB and computes a breakover angle:

Then it compares that 14 degrees against your ramp’s own angle and prints one plain verdict: “Should clear the transition” when the ramp angle sits below the breakover angle, or “Will likely drag or high-center, use a longer ramp or a lower angle” when it does not.

We made that verdict the headline result on purpose. In our competitor pass, ez-access hides the same calculation behind an “Advanced” toggle and the rest never compute it at all, so people load blind and learn the answer as a scrape. Putting it first is the entire reason this tool exists.

What the verdict deliberately leaves out

The breakover formula is a clean geometric approximation, and clean means it ignores things the driveway does not. It assumes the low point sits at the wheelbase midpoint. It knows nothing about a bumper or hitch hanging past the axle, tires and suspension squatting under a loaded vehicle, or the rounded lip and transition radius of the ramp itself. Any one of those can turn a computed “should clear” into a real drag. That is why a pass says “should,” never “will,” and why a fixed line stays on screen whenever a verdict shows: “Approximation. Ignores overhang and tire deflection. Treat as a guide, not a guarantee.” Measure clearance at the true lowest point, leave margin for the squat of a loaded vehicle, and when the verdict lands close, treat close as a fail.

Two numbers, both checked in under a minute, standing next to the trailer where you would otherwise be guessing.

That is the whole job of the tool.

Frequently asked questions