Gradeability is one of the most confusing elements of selecting access machinery, yet is it one of the most important to consider for your project to go smoothly. So, what is it?
What is Gradeability?
Gradeability is the steepest gradient a machine can climb, compared to the Operating Angle which is the steepest gradient a machine will operate on.
In the world of access, gradeability specifically refers to the size of the incline that a machine has the capacity to climb up or down. This calculation is done with the machine in the stowed (lowered) position.
How to calculate gradeability?
Gradeability is widely calculated as a percentage rather than degrees. It can be confusing to convert between these two values and to visualise a percentage value in terms of an angle.
A 45° angle equates to 100% gradeability.
Formula to convert a percentage to degrees:
Degrees = Tan-1 (Slope Percent/100)
Occasionally access machinery specifications may show inclines expressed as degrees. This could be confusing if you are comparing between machines and both are expressed in different values.
Formula to convert degrees to a percentage:
Percentage = [ Tan ( Degrees ) ] x 100
How to choose a machine to move across an incline?
As a general rule Diesel machines (also known as rough terrain or all terrains) are equipped with rough terrain tyres and often with 4WD, giving the machine enough grunt to help propel it up a steeper gradient.
When viewing a product on Duralift’s website, “Gradeability” is listed under the specifications tab. To help make things easy we have done the calculation for you and shown this value as both percentage and degrees.
What is an Operating or Working Angle?
It is important to note that having a high gradeability does not mean the machine can operate on this same angle. The operating angle is the gradient at which the machine will elevate to full height. This is typically 5 degrees or less for most common machines. Or around 10 degrees for machines with outriggers or stabilisers.
New machines are coming onto the market in recent years that can operate on steeper gradients. The Duralift website shows some of these machines such as the Jack Boom, Jibbi Boom and Athena Scissor Lift which can operate on inclines up to a huge 20 degrees! Check them out here!
Apps to read inclines
If you need to move across an incline or work on one we recommend installing a free App on your phone. Search “inclinometer” on your Google Play or App Store for a multitude of available options.
Contact Duralift on 1300 580 580 and our friendly team can recommend the right machine for your project and budget.