The Garmin dezl 770LMTHD was built specifically for truck drivers, and even years after its release, it’s still widely used thanks to its large 7-inch display, truck-specific routing, and reliable traffic data.
But if you’ve spent any time using it in a real cab, you already know the biggest issue:
Mounting it properly is not as simple as Garmin makes it look.
The included mount works — but in a truck, “works” isn’t good enough. Long windshield reach, vibration, and visibility all make mounting far more important than it would be in a standard car.
How the dezl 770LMTHD Mounting System Works
The dezl 770LMTHD uses Garmin’s standard automotive mounting system:
- Magnetic cradle (quick attach/detach)
- 17mm ball socket on the back
This is the same system used across many Garmin Nuvi and dezl units, which is good news — because it gives you access to a wide range of better mounting options.
And for a GPS this large, upgrading the mount is almost mandatory.
Why the Stock Mount Falls Short
The included suction mount is fine for smaller vehicles, but trucks create different challenges:
- Long distance to the windshield
- More vibration
- Larger dash area
The result? The GPS often ends up too far away, poorly positioned, or shaky.
This is why most truck setups benefit from either a stronger suction mount or an extended arm solution.
Best Mounts for Garmin dezl 770LMTHD
1. Arkon Heavy-Duty Suction Mount (Best Overall)
This is the most reliable upgrade over the stock Garmin mount. These fitt he cradle that came with your GPS.
The Arkon suction mount uses the same 17mm ball system, so your existing magnetic cradle snaps right onto it.
- Strong suction with locking lever
- Better stability than stock
- Includes dash disk option
2. Arkon Extended Arm Mount (Best for Trucks)
This is where things get serious.
Truck windshields sit far away, and the stock mount simply doesn’t reach far enough. The extended arm mount solves that problem with a long adjustable arm.
- 14–18 inch extension
- Positions GPS closer to driver
- Metal arm for improved stability
3. Garmin Bean Bag Mount (Best No-Install Option)
If you don’t want anything attached to your windshield or dashboard, the bean bag mount is still one of the simplest solutions available.
- No installation required
- Easy to move between vehicles
- Good for temporary setups
This is especially useful if you’re switching between trucks or using a company vehicle.
Important: Don’t Lose the Traffic Cable
This is something most people don’t realize until it’s too late.
The traffic subscription on the dezl 770LMTHD is tied to the power cable, not the GPS unit.
If you lose it, replacing it is not cheap — and a standard charger will not give you traffic data.
Keep it with the unit at all times.
Mounting Strategy by Vehicle Type
Pickup trucks / smaller cabs:
- Standard suction mount upgrade works well
Semi trucks / large rigs:
- Extended arm mount is strongly recommended
Temporary / multi-vehicle use:
- Bean bag mount
Common Mounting Mistakes
- Using the stock mount long-term
- Mounting too far away from driver
- Ignoring vibration in large vehicles
- Overextending weak mounts
Related Mount Guides
Bottom Line
The Garmin dezl 770LMTHD is still a solid truck GPS — but only if it’s mounted correctly.
The key is understanding that you don’t need a new cradle — you need a better 17mm mount system.
For most setups, upgrading to a stronger suction mount or extended arm will dramatically improve usability and visibility.
