If a Garmin mount doesn’t fit, the problem is almost always the same: the wrong ball size. Garmin has used the 17mm ball system for years across most automotive GPS devices, but newer large-screen models like the OTR and RV series now use a 22mm ball. These two systems are not compatible, and that’s where most frustration starts.
This guide breaks down exactly how the two systems work, which Garmin models use each, and how to make sure you buy a mount that actually fits the first time.
Quick answer: If your Garmin uses a magnetic powered cradle and has a large screen (8”+), it almost certainly uses a 22mm ball. Older and smaller Garmin GPS units use 17mm.
Garmin 17mm vs 22mm: The Core Difference
The difference between 17mm and 22mm mounts comes down to size, strength, and intended use.
| Feature | 17mm Ball | 22mm Ball |
|---|---|---|
| Common Use | Cars / small GPS | Trucks / RV / large GPS |
| Device Size | 5″–7″ | 8″–10″ |
| Strength | Moderate | Heavy-duty |
| Compatibility | Very wide | Limited but growing |
The key takeaway is simple: these two systems do not mix. A 17mm mount will not fit a 22mm socket, and there is no clean workaround without changing components.
Which Garmin Models Use 17mm?
The 17mm ball system is still the most common across Garmin’s lineup. If the GPS is smaller and designed primarily for passenger vehicles, it almost always uses 17mm.
- Garmin Drive series
- Garmin DriveSmart series
- Garmin DriveAssist
- Most older Garmin nuvi models
- Many dezl truck units (smaller screens)
This is why the aftermarket is flooded with 17mm mounts. It has been the default for years.
Which Garmin Models Use 22mm?
The 22mm system is used on Garmin’s larger, premium GPS units. These devices are heavier and require a stronger mounting system.
- Garmin OTR 800, 810, 820
- Garmin OTR 1000, 1010, 1020
- Garmin RV 890, 895
- Garmin RV 1090, 1095
- Garmin DriveSmart 86
- Newer large dezl models
These devices almost always include a magnetic powered cradle, which connects to the mount via the 22mm socket.
Why 22mm Exists (And Why It Matters)
The move to 22mm wasn’t random. Larger GPS units create more stress on mounts, especially in trucks and RVs where vibration is higher.
- More weight = more leverage on the mount arm
- Longer arms = more movement and vibration
- Commercial use = higher durability requirements
The 22mm ball provides a stronger connection and better stability, especially when paired with longer mounting arms or fixed AMPS installations.
Best Mount Options for 22mm Garmin Devices
Once it’s clear that a GPS uses 22mm, the focus shifts to finding mounts that actually support it. This is where most people run into problems, because the market is still heavily dominated by 17mm products.
There aren’t many of these because this size is still relatively new and most manufacturers are still geared up for the smaller automotive sector which uses the smaller 17mm ball.
22mm Ball Flexible Suction Mount (Best Overall)
This is a basic suction cup mount with a flexible gooseneck. The mount features a vaccum suction cup that is activated by pressing the lever down. Garmin doesn’t offer one like this, so we are recommendiong an aftermarket selection.
AMPS to 22mm Ball Mount (Best for VSM Mounts)
This is an important upgrade path. An AMPS-based mount allows the GPS to be installed on vehicle-specific brackets, flat surfaces, or custom mounting systems. These attach to some of the mainstream vehicle specific mounts like Pro-Clip. The ball attaches to the socket on the back of the cradle received with your GPS.
Extended Suction Mount (Best for Trucks)
Long-arm suction mounts help position the GPS correctly in large cabins where standard mounts fall short. This mount has a metal extendable arm that increases the length to over 18 inches. The 22mm ball on the end fits the socket on the back of the Garmin cradle. This is the heaviest duty mount of the four we recommend.
Common Mistakes to Avoid
- Buying a 17mm mount for a 22mm device
- Assuming all Garmin mounts are interchangeable
- Ignoring the magnetic cradle requirement
- Choosing weak mounts for large GPS units
Bottom Line
The difference between Garmin 17mm and 22mm mounts is simple once understood, but it causes a lot of confusion during purchase. Smaller GPS units use 17mm. Larger, newer devices use 22mm. They are not compatible.
Choosing the correct mount comes down to identifying the ball size first. Once that is clear, the rest of the mounting decision becomes straightforward.
