Club Car's owner's manual states:
My explanation:
A 20 degree incline angle is close to a 37% grade so the answer is 20% not 20 degrees.
Incline is also called pitch or rise and is a ratio of rise divided by run.
The percentage of incline is rise/run x 100.
Here is a example of incline:
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Grade_dimension.svg/250px-Grade_dimension.svg.png)
Here are some inclines vs percentages:
Avoid driving the vehicle on slopes exceeding 20% incline.
A 20 degree incline angle is close to a 37% grade so the answer is 20% not 20 degrees.
Incline is also called pitch or rise and is a ratio of rise divided by run.
The percentage of incline is rise/run x 100.
Here is a example of incline:
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Grade_dimension.svg/250px-Grade_dimension.svg.png)
Here are some inclines vs percentages:
![](http://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Grades_degrees.svg/767px-Grades_degrees.svg.png)