There are a few things to consider when choosing a motorcycle ramp: weight capacity, length, and width.
Weight capacity is important because you want to make sure the ramp can support the weight of your motorcycle. Length is important because you need to make sure the ramp is long enough to get your motorcycle up onto whatever surface you're trying to access. Width is important because you need to make sure the ramp is wide enough for your motorcycle's tires.
In addition to those three things, you also want to consider what type of material the ramp is made from. Aluminum ramps are lightweight and easy to transport, but they may not be as durable as steel ramps. Steel ramps are more durable but they're also heavier and more difficult to move around.