Successfully identifying the perfect ramp size for your ATV can be a daunting task. It's important to be aware of several important figures to choose the right ramp which is compatible with your ATV: Wheelbase - This is the horizontal distance between the center of the rear wheel to the front wheel. Ground Clearance - Measuring the length between the lowest part of your ATV (excluding its tires and wheels) to the ground will generate this figure. Loading Height/Rise - In order to generate this number, measure the distance between the ground and the highest point of the trailer which the ATV will be loaded upon. Now comes the difficult part; configuring these numbers into an equation. To do this, we recommend using a Ramp Length Calculator. Our favorite has to be DiscountRamps calculator, for which you'll find the link below. Yet if you're a whiz at Maths, follow the formula below: Rise / (Ground Clearance / (Wheelbase x 0.5) 0.5 )) = Result