RAM suction cup mounts are still some of the best windshield and glass-mounting solutions available, but they are not all the same. That is where a lot of buyers go wrong. They see “RAM suction mount,” assume they all work the same way, and end up with either more mount than they need or not enough mount for the device they are trying to hold.
The good news is that the RAM lineup is actually pretty easy to understand once you break it into three categories: the standard 3.3-inch suction cup mounts, the lower-profile 2.75-inch versions, and the heavier-duty dual suction setups for larger tablets and more demanding installs. The right choice depends on the weight of the device, how much reach you need, and how permanent or flexible you want the setup to be.
How RAM Suction Cup Mounts Work
Most RAM suction cup mounts use the company’s Twist-Lock design. In simple terms, you place the suction cup on a smooth surface, twist the locking mechanism, and create a stronger hold than a generic press-on suction cup normally gives you. RAM’s official product pages still specify that these bases are designed for glass and other non-porous plastic surfaces, and that they can also be used with RAM adhesive disks when needed.
That is an important detail because suction cup mounts are only as good as the surface they are attached to. Clean, smooth glass is ideal. Textured surfaces, dirty windshields, and rough dashboards are where people run into trouble.
If you want the bigger picture on how bases, arms, and holders all work together, see our RAM Mount system guide.
The Three Main RAM Suction Cup Options
1. RAM-B-166U: Standard 3.3-Inch Twist-Lock Suction Cup Mount
The RAM-B-166U is still one of the core RAM suction cup kits. It is a 3.3-inch diameter Twist-Lock suction cup base with a standard-length double socket arm and diamond base adapter. That makes it one of the best starting points for a phone, GPS unit, or a light tablet setup that uses a B-size 1-inch ball system.
In real-world use, this is the “default good choice” for a lot of vehicle setups. It gives you more suction area than the low-profile version, which helps with stability, and the standard arm gives enough adjustability for windshield mounting without being overly long. It is the kind of mount that works well when you want a proven all-around option and are not trying to keep the footprint especially small.
2. RAP-B-166-2U: 2.75-Inch Low-Profile Twist Lock Suction Cup Mount
The RAP-B-166-2U is RAM’s lower-profile 2.75-inch Twist-Lock suction option. RAM still lists it as using a 2.75-inch suction cup base, double socket arm, and diamond base adapter, again in the B-size 1-inch ball system.
This is the smarter choice when the device is light and you want less bulk on the windshield. For phones, compact GPS units, and lighter-use installs, the smaller footprint can be a real advantage. It takes up less visual space and often looks cleaner in smaller vehicles.
The tradeoff is pretty simple: less suction area means it is not the first thing I would choose for heavier setups. That does not make it weak. It just means it is better matched to lighter devices.
3. RAP-B-166U and RAP-B-166U-A: Composite Versions
RAM also still sells composite versions of the standard 3.3-inch Twist-Lock suction mount. The RAP-B-166U uses the standard arm, while the RAP-B-166U-A uses a short arm. RAM’s product pages still describe both as 3.3-inch suction cup mounts built around the B-size system.
The short-arm version deserves special attention because a shorter arm often improves stability. If you do not need extra reach, shorter is usually better. Less arm means less leverage, and less leverage means less movement.
This is one of those quiet real-world truths about RAM systems: people often buy more arm than they actually need. If the mount will be close to where you want the device anyway, the short-arm version is often the cleaner answer.
What About Tablets?
This is where people should slow down a bit. A suction cup mount that works beautifully for a phone may not be the right answer for a tablet, especially a full-size one. RAM still sells single-suction and dual-suction tablet kits using Tab-Tite holders, and the dual-suction approach remains the better fit for larger tablets or heavier-duty windshield applications. RAM’s current dual-suction tablet kits still use two Twist-Lock suction cups and a double socket arm to spread the load better than a single cup can.
If you are mounting a smaller tablet in a low-vibration vehicle, a single suction solution may still be workable. But once the device gets larger, heavier, or more awkwardly positioned, dual suction becomes the safer path.
For broader tablet options, see our best tablet mounts for car use guide.
We provide the link for the triple mounting base. Add the base, arm and cradle to complete the solution.
Which RAM Suction Cup Mount Is Best?
Here is the simplest way to think about it:
- Want the safest all-around default? Choose the standard 3.3-inch suction mount.
- Want a smaller, cleaner windshield setup for a light device? Choose the 2.75-inch low-profile version.
- Want to mount a tablet or need extra support? Move up to a dual suction configuration.
Most buyers do not need to overcomplicate it beyond that.
Common Mistakes with RAM Suction Cup Mounts
- Using them on the wrong surface: smooth glass and other non-porous surfaces are what these are made for.
- Choosing too small a suction cup for the device: lighter mounts are for lighter devices.
- Using too much arm: extra reach often creates more movement.
- Ignoring local windshield-mount restrictions: some states limit what can be attached to the windshield. If that applies to you, use a legal alternative or an adhesive disk where appropriate.
If you need more on that last point, see our guide to windshield-mount laws and restrictions.
Are RAM Suction Cup Mounts Good for Motorcycles?
Generally, no. That has not really changed. RAM suction mounts are designed around smooth-surface suction use in lower-vibration environments like cars, trucks, industrial vehicles, and some stationary applications. Motorcycles create a different vibration profile, and that is not where I would want to rely on suction long-term.
For bike-specific mounting, see our motorcycle mount guides.
Related RAM and Mount Guides
- RAM Mounts Explained
- RAM Ball Sizes Explained
- RAM Arms Guide
- RAM Mount Extensions
- RAM Mount Bases Guide
- GPS Mount Guides
- Phone Mount Guides
Bottom Line
RAM suction cup mounts are excellent, but the right one depends on the job. The standard 3.3-inch Twist-Lock mount remains the best all-around choice for most phones and GPS units. The 2.75-inch low-profile version is a smart alternative when you want less bulk for a lighter device. And if you are moving into tablet territory, especially on glass, dual suction setups are still the better answer.
The main thing is not to treat all RAM suction mounts as interchangeable. They are related, but they are not identical. Match the suction base size and overall setup to the weight of the device and the kind of environment you are using it in, and you will get much better results.
