Car Shipping 101: Important Angles of Car Shipping
Loading Ramp Angle
Unfortunately, this angle is not always defined by you in the shipping process; it is chosen according to the method of transportation and whether your vehicle is being loaded on the top or bottom of the trailer or railcar.
When driving your vehicle up or down a ramp it will transition from a level surface to an incline to a level surface again, meaning your vehicle could get caught on the front or rear bumpers during loading/unloading or it could get caught on the undercarriage during the transition from the ramp incline to the upper level surface and vice versa.
To prevent your vehicle from getting damaged while loading on an open trailer or railcar, here are a few important measurements and angles that you should know.
The angle between the imaginary line extending from the upper surface of the ramp and its incline.
On a ramp, break-over angle can be described as the angle between the imaginary line extending from the upper level surface of the ramp and its incline.
Knowing the break-over angle of your vehicle can protect the bottom of your vehicle between your wheels. It is derived from two main measurements; the ground clearance of your vehicle which is the distance between the ground and the lowest part of your vehicle, and the midpoint of your wheelbase which is half of the distance between the centers of your wheels. The break-over angle determines the maximum supplementary angle that your vehicle can drive over without any part of your vehicle touching the apex of said angle.
This is important when transporting vehicles as they are loaded onto open trailers or railcars using ramps with changes in slopes. If you were to drive a vehicle up a ramp with a supplementary angle that is greater than the break-over angle for said vehicle then it will make contact with the apex of the angle and could prevent the vehicle from continuing any further in its direction of travel, and possibly even completely immobilize the vehicle.
Follow these steps to find the break-over angle of your vehicle:
- Position your vehicle on a flat surface.
- Measure from the ground to the lowest part of your vehicle between your wheels.
- Measure the wheelbase of your vehicle. You can find this by measuring the distance between the centers of your front and rear wheels on the same side of your vehicle.
- Find the midpoint of your wheelbase by dividing your wheelbase measurement in 2.
- Divide your measurement from step 2 (ground clearance) by your measurement from step 4 (wheelbase midpoint).
- Take the result from step 5 and use the “inverse tan” (tan-1) function on it.
- To find the final break-over angle, take the angle you got from step 6 and double it.
When doing your measurements, ensure that you use the same units of measurement for all steps.
Example: 2020 Honda Civic DX
Ground clearance: 125mm
Wheelbase midpoint = 2700mm / 2 = 1350mm
125/1350 = 0.09259
Tan-1(0.09259) = 5.29°
5.29° x 2 = 10.58° break-over angle
If you drive a 2020 Honda Civic over a surface with a supplementary angle equal to or greater than 10.58° then you could get the vehicle stuck or damage its undercarriage.
Overhang is the length of a vehicle that extends beyond the wheelbase at the front and rear. They are normally referred to separately as front overhang and rear overhang. These overhangs are typically the front and rear bumper of a vehicle, but can also be an air dam or defuser. Regardless of what exactly causes the overhang, they can affect the ability to traverse steep inclines.
Along with ground clearance, the length of overhangs affect the approach and departure angles. The longer the front overhang, the smaller the approach angle, and can therefore affect the vehicle’s ability to climb or descend steep ramps without damaging the vehicle.
Approach and Departure Angles
Approach angle is the maximum angle of a ramp onto which a vehicle can ascend from a horizontal plane without interference. It is defined as the angle created by an imaginary line between the base of your front tire and the lowest part of your front overhang.
Departure angle is the counterpart of approach angle, it is the maximum angle that a vehicle can descend a ramp without causing damage and is defined as the angle created by an imaginary line between the base of your rear wheel and the lowest part of your rear bumper.
Along with transportation limitations, approach and departure angles are important for off-roading activities and indicate how steep of an obstacle, like a rock or log, the vehicle can negotiate according to its body shape.
An easy way to find out your approach angle is to take a tape measure and place it at the base of your front wheel and raise it until it hits the underside of your car. Once you have done this, measure the distance between the 36” mark on the tape measure and the ground in inches. Then take that number and input it into the calculator at this link: https://www.raceramps.com/angleofapproachcalculator.aspx
We tested this on a 2010 Honda Civic and found that it can safely ascend an incline of 16.9°.
Approach and departure angles are important for off-roading activities and indicate how steep of an obstacle, like a rock or log, the vehicle can negotiate according to its body shape.
Affecting These Factors
If, once you’ve learned these measurements and angles, you are concerned that your vehicle has too low of a break-over angle or approach and departure angles and wouldn’t be safe to ship on a standard open carrier transport or railcar, there are a couple things that you can do to affect these angles. Depending on your vehicle, these options might not be feasible.
The first option is to increase the ground clearance of your vehicle. This can be done by swapping out your suspension for higher ride height or if your vehicle is equipped with air ride or coil-overs it could be as simple as tweaking those settings. When you increase your ground clearance you directly affect both the break-over angle and the approach and departure angles.
The other option is to modify your front or rear bumper to make them shorter. This option is mainly for vehicles that have been modified with air dams or diffusers where they can be easily removed or replaced with the factory supplied bumpers. When you reduce the length of your bumpers it will have a positive effect on the incline that your vehicle can ascend without being damaged.
If you are unable to do these modifications or doing these options don’t make any significant difference, the best option is to ship your vehicle with an enclosed truck. Most enclosed trucks are equipped with long low-angle ramps or hydraulic lift gates designed specifically for vehicles with these specifications.
Measuring your vehicle’s ground clearance is an easy way to figure out what the best way to ship your vehicle is, but upon closer inspection it does not always have the final say.
For example, if you own a Fiat 500 with a low ground clearance of 4.5” you may assume that it won’t be safe to ship via an open carrier truck as it falls under the “safe” measurement of 5.5”. However, if you take into consideration the wheelbase of a 2019 Fiat 500 is 90.6”, this gives it s break-over angle of slightly greater than a 2020 Honda Civic at 11.34°. Couple this with the fact that the wheels are situated so close to the front and rear of the vehicle, reducing the overhang, it makes the approach and departure angles almost negligible, making it safe for loading on any open transport.
Get to know these small but important details of your vehicle and you could save yourself from some unnecessary costs in both shipping and non-shipping scenarios.