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How Do RAM Mounts Work?

What is RAM

RAM, or Round-A-Mount, was first established in 1992 and has since shown itself to be a consistently innovative company. Rapidly adapting their products to accommodate new trends and technologies, they continue to evolve their products in order to offer a huge variety of mounting options for all manner of devices. The brand has become the quintessential mount producer for all purposes including rugged vehicle, industrial, military and defence, material handling, commercial uses.

Basic Mount setup

To begin on how to set up your mount you need to understand the basics. Fundamentally, there are three main factors for any mount setup – The cradle, the arm (joiner) and the mounts. We’ve provided an example below:

1. The Cradle holds your unit (GPS, Phone, Laptop, etc).

2. The first mount joins to the Cradle. The arm connects to the first mount unit.

3. The second mount joins to the other end of the arm.

4. The second mount is screwed or suctioned to the surface.



Mount Unit

Arm Unit

Mount Unit

Triple Suction Mount

How Do Ram Mounts Work

While this style of cradle, mount and arm is the common setup style, there are hundreds of variations that exist to offer mounting solutions for practically any environmental or specific user scenarios. An example of this might be a user that has a large GPS unit that needs to remain secure. In this case, a triple suction mount would offer the best stability to hold the weight of the GPS unit without the unit vibrating and making it difficult to read. Alternatively, the user may feel that a suction mount won’t be able to handle the strain and might decide to go with a more permanent screw mount solution.

RAM Mount Ball Sizes

RAM uses a sizing guide to help customers choose which mounting option suits them. There are five sizes that RAM produce, and each size is related to the diameter of the connecting ball. Each size is lettered A through to E from smallest to largest. Mounts of the same ball size are compatible with one another, so a B-sized RAM part is compatible with all other B-sized RAM parts like arms or cradles. As such two different sizes are not compatible with one another, you can’t fit a B-sized RAM component with a C-sized RAM component. To make sure you've got the right size you can check the code for the component. As with all RAM products, the size of the ball is in the part name. Take for example the component RAM-B-202, the letter ‘B’ in the product name references the size of the ball. So, the RAM-B-202 has a 1” Ball.

*Note - C size components don’t use a letter prefix and so the name of the part has no letter and is instead left blank (e.g. RAM-202).

Weight Capacity Table

B size 1" ball mount

up to 2.25kg weight (approx 5 lbs) 

C size 1.5" ball mount

up to 4.5kg weight (approx 10 lbs) 

D size 2.25" ball mount

up to 6.75kg weight (approx 15 lbs) 

E size 3.38" ball mount

up to 9kg weight (approx 20 lbs)


The size of the ball also determines how much weight the mount can support, a B size unit can support typical handheld devices up to 2.2Kg depending on the environment. The most common mount size is B but they follow a scale in size featured below:


The larger you go will increase the units weight capacity. To give you an idea, an E size ball has a diameter of 3.38” or 8.6cm in terms of weight capacity this unit us rated to hold up to 11Kg. This unit generally forms the basis of any mount setup. An example of this unit’s code would be RAM-E-202.


As mentioned in our RAM tutorial video, the Johnny Appleseed website includes a handy compatibility tab on all our products. This will allow you to make sure that every part is compatible.

RAM Compatibility Chart

How RAM products are made

Most base units are made from a Marine Grade Aluminum, the 1-inch ball is made from an elastomeric rubber ball. This helps ensure that the arm unit can socket over the unit and stay firmly gripped. The rubber also helps dampen shock and vibration that can travel through the base of the unit. 

RAM AMPs Pattern Guide

The unit has 7 holes positioned in an AMPS style to accommodate most cradles and Garmin GPS units. AMPS is the industry standard pattern for vehicle mount units. The red outline below shows the standard rectangular AMPS pattern. From centre to centre 1.5 inches (38.1mm) and 1.18 inches (29.972mm). The holes drilled into the unit are 5.5mm. The mounting unit is used as either a base screw down unit or as a cradle mount to your device. The unit specifications featured below are for RAM-B size units you can also tell this from the code for the unit RAM-B-202U where the B signifies the unit size and compatibility with other RAM units. As a side note, the "U" in this code reflects products packed in a poly bag.

*The Round Ball mounts utilise the AMPS hole style pattern for sizes A-B and C. The large D and E sizes follow a different pattern which is explained in the following section


RAM Compatibility Chart

RAM D & E size Screw Mounts

The D & E Size mounts feature a 4 mounting hole pattern style. Three holes in a 120-degree style and two holes in a 180-degree style. The diameter of each hole drilled into the plate is 9.1mm with a plate thickness of 8mm. 

D Size

RAM Compatibility Chart

E Size


All RAM products come with a lifetime warranty excluding RAM units with an electronic component which come with a 3-year warranty.  

More RAM Guides

RAM Base Mounts

RAM Arm Units & Connectors

RAM Cradles

Click the button below to view the full RAM Product Range at Johnny Appleseed GPS

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