RAM ATV/Side By Side Rail Mount for Garmin Astro 320 / GPSMAP 62 & 64 Series
Same trusted rail base, this time finished with a form-fit cradle built specifically for your Garmin handheld.
This is the RAM-B-149Z-2 base and arm from above, but with the universal AMPS plate replaced by a purpose-built RAM Form-Fit cradle for Garmin's Astro 320 and GPSMAP 62 & 64 series handheld GPS units. Where the diamond-plate version needs you to add your own cradle, this one is ready to run as soon as it's clamped on.
What's in the kit
In the box: strap clamp adapter, two U-bolts (0.5"–1.25" rails), a B-size medium double socket arm (3" socket-to-socket), and RAM's Form-Fit composite cradle molded specifically for the Garmin Astro 320 and GPSMAP 62 & 64 series body shape — it grips the unit's exact housing rather than a generic clamp, so the device seats securely with all buttons and ports accessible.
The base and arm are powder-coated marine-grade aluminum; the Garmin-specific cradle is high-strength composite.
How RAM's modular system works
Every RAM product on this page is part of the same modular system used across RAM's entire catalog. Once you understand how it fits together, every other RAM accessory we sell will make sense too.
- A base — clamps, bolts, or straps onto the vehicle (a rail, a roll bar, a dash, a windshield, or a device's own housing).
- An arm — connects two RAM balls together. It can be locked at any angle, so once mounted you can tilt, rotate, and reposition the device freely, then lock it firmly in place by hand.
- A cradle or holder — grips the specific device (tablet, phone, GPS unit, camera).
The ball size determines what it can carry. RAM uses five ball sizes, each rated for a different weight/duty class:
| Ball size | What it's for |
| A Size | Rarely used; costs more to make than B Size but carries less. Reserved for small, low-profile items like security cameras. |
| B Size — used on this product | RAM's most common size, standard duty. Recommended for phones, GPS units, and light tablets in normal use. |
| C Size | Heavy duty. Used for larger tablets, handheld computers/scanners, CB radios, and anything mounted somewhere with a lot of vibration or shock — exactly the case in a tractor, ATV or UTV cab. |
| D / E Size | Reserved for large monitors and specialist/military equipment; rarely needed outside those cases. |
Rule of thumb: if the mount will live somewhere that's frequently jostled, vibrated, or under constant load — an off-road vehicle like a tractor, ATV or UTV — RAM recommends stepping up to the larger ball size (C rather than B) for extra stability, even if a lighter mount would technically hold the device's weight.
No tools required, on purpose. RAM arms are designed to be tightened by hand only — there's no official torque spec, because the ball-and-socket joint is meant to be adjustable in the field without a wrench. If hand-tightening doesn't hold your device firmly, that's usually a sign the ball size is undersized for the device — sizing up solves it, rather than over-tightening.
Aluminum or composite — both are built for the outdoors. RAM mounts are made from marine-grade aluminum or high-strength composite, interchangeably depending on the product; both carry a lifetime warranty and similar weight ratings. Aluminum's powder-coat finish handles rough vibration and shock slightly better; composite skips the paint entirely, so it has nothing to chip and is often preferred in high-corrosion or salt-air environments. Neither choice is worse — it's a trade-off between finish and environment.
Specifications
| Ball size | B Size (1" / 25 mm) |
| Arm length | Medium, 3" socket-to-socket (76 mm) |
| Compatible devices | Garmin Astro 320, GPSMAP 62 series, GPSMAP 64 series |
| U-bolt clamp range | 0.5"–1.25" (12.7–31.75 mm) |
| Strap clamp range | 1.57"–3.15" (40–80 mm) |
| Weight capacity, standard use | 2 lbs (0.9 kg) |
| Weight capacity, heavy-duty use | 1 lb (0.45 kg) |
| Materials | Marine-grade aluminum, high-strength composite |
| Included | Complete kit: base + arm + Garmin Form-Fit cradle |
| Warranty | Lifetime warranty |
Frequently asked questions
Which Garmin models does this fit?
The Garmin Astro 320 and the GPSMAP 62 and 64 series handhelds — the cradle is molded to their specific body shape, not a universal clamp.
Is this a complete mount, or do I need anything else?
It's complete — rail base, arm and the Garmin-specific cradle are all included. Clamp it to a roll bar or rail, snap in the GPS unit, and adjust the arm by hand.
Why B size for a GPS handheld?
A handheld GPS unit is light and compact, well within RAM's standard-duty B-size rating — the same size RAM recommends for phones and GPS units generally.
Can I access the buttons and ports with the unit mounted?
Yes — the Form-Fit design follows the device's own housing shape rather than covering it with a generic clamp, so the controls stay reachable.
How wide a rail or handlebar does it fit?
U-bolts for 0.5"–1.25" (12.7–31.75 mm) diameter tubing, and the strap clamp for 1.57"–3.15" (40–80 mm) diameter rails or bars — the same range as the diamond-base version above.
Not sure which RAM combination fits your tablet, phone or GPS unit? Contact us and we'll help you put together the right base, arm and cradle.