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The Diono Rainier 2AX is a luxury convertible car seat, rated to hold and protect kids from 5-65 pounds and up to 57 inches in height.
Diono car seats are famous for being foldable, so they collapse and tuck away easily for storage or transport, which is especially impressive given that this is a full-size car seat with a full metal frame and deep headwings for extra protection.
This impressive car seat also comes in a wide range of sporty colors and fabrics, to look great no matter what your style!
Overview of Diono Rainier 2AX
The Diono Rainier 2AX is a fairly big convertible car seat, at 28.5 inches high and nearly 28 pounds in weight. But it's just 18 inches wide, for easy 2-across installations, and has Diono's famous fold-away feature, making it super easy to collapse for travel or storage, so it's relatively easy to handle despite the size and weight.
The extra size and weight are worth it, because they are the result of the full steel alloy frame that provides extra safety and security, and the generous size allows this car seat to grow along with your child, up to a height of 57 inches. And, despite the generous headwings, it has a low profile that makes it easy to access, so that kids can climb into the seat themselves as they grow.
What are this model’s NHTSA ratings? All car seats sold in the US must meet strict federal safety standards, so the NHTSA does not rate car seats for safety. Instead, they offer ratings and evaluations for ease of use. According to the NHTSA, the Diono Rainier 2AX has earned (for the forward-facing installation):
- Side impact protection? Yes
- Energy-absorbing base? Energy-absorbing EPS foam
- Metal frame? Yes
Ease of Use
Does this model have:
Ease of Installation
Comfort and Quality
Diono Rainier 2AX Specs
Rear-facing weight limit
5 -50 pounds
Rear-facing height limit
Forward-facing weight limit
Seated torso height
Overall maximum height
Up to 57 inches
Diono Rainier 2AX Features
Ease of use
Quality and comfort features
Who is the Diono Rainier 2AX Most Suitable For?
The Diono Rainier 2AX is a big, heavy car seat. Even though it folds flat for transport and storage, it's cumbersome to move from place to place or vehicle to vehicle. The instructions can be a bit difficult to decipher, and it scores fairly low on ease of use.
For those reasons, this big, heavy, plush car seat is best used in a large vehicle with lots of leg room, particularly in rear-facing installations, and not a good choice for car seats that need to change vehicles often. Once it's secured correctly, particularly when rear-facing, most parents are reluctant to move it again unless it's absolutely necessary.
For parents with a big vehicle and who want a big, safe car seat that is easy for kids to get into and out of themselves, the Diono Rainier 2AX is a good choice. The slim width also makes it a good choice for two-across car seat configurations in large vehicles.
What is included with the Diono Rainier 2AX?
This carseat comes with a newborn insert pillow. Many parents find it helpful to add the Diono angle adjuster, to with help rear-facing installations:
Pros and Cons of Diono Rainier 2AX
Diono Rainier 2AX Installation
The Diono YouTube channel has many videos that can help you make the most of this car seat, and installation of their convertible car seats in general, but none that cover the specific installation of this model.
However, YouTuber The Car Seat Lady has helpful videos that show step-by-step installation for rear-facing with LATCH installation:
and forward-facing with a seat belt and tether:
Diono Rainier 2AX Manual
The Diono Rainier 2AX user manual is available here:
Diono Rainier 2AX vs. Diono Rainier 2AXT
The Diono Rainier 2AX and the Diono Rainier 2AXT are extremely similar convertible car seats. They both have the same steel frame and side impact protection. They both fold flat for transport and storage. They are installed in the same way, and have some similar installation and ease-of-use issues.
While the Radian 2AX is a big, heavy car seat, the Radian 2AXT is the same size but a little heavier, at just over 31 pounds. That's because the Radian 2AXT is a 4-in-1, that goes all the way from infants, with the included newborn insert pillow, to school age children up to 120 pounds when it converts to a booster seat. It also has adjustable headwings, and comes in a wider range of colors. You can even get the Diono Rainier 2AXT upholstered in pricey Marino wool for a luxurious touch.
The Diono Rainier 2AXT is significantly more expensive than the Rainier 2AX, even without upgrading to luxury upholstery. If you want simplicity of a single car seat that will protect your child for up to 8 years or 120 pounds, it may be worth the additional cost for the ability to set-it-and-forget-it.
If price is an issue, you may want to stick with the Diono Rainier 2AX, and buy a booster seat when your child is ready for one. This path will not only save you money, but may also help you get a better fit for your older child. After all, when a child is a baby, it is difficult to anticipate how quickly or how large they will grow, and it's hard to choose a product that will fit them well for all of their first 8 years.
The Diono Rainier family of car seats only have 5 shoulder harness positions and 3 buckle positions, so there may be issues with getting the right fit over time. Buying a separate car booster seat when the child is ready for one makes sure the fit is right and your child is comfortable. And, in the case of the Diono Rainier 2AX vs. the Diono Rainier 2AXT, it will save you money as well.
Diono Rainier Car Seat User Review
The Diono Rainier 2AX is a big, plush car seat that is high on safety and a bit lower on usability. Some parents love the rugged, heavy-duty feel of this convertible car seat, and appreciate how it makes their kids cozy and safe. Some parents with smaller vehicles or who have to frequently move the car seat find it too difficult to install correctly and too cumbersome to move easily.
It doesn't get great reviews for the ease of installation or the quality of the instructions, but it does provide a safe and comfortable ride to kids for the first several years of their lives. It's a high quality car seat with the durable construction that will absorb impact and protect kids in the event of a collision.
Diono Rainier 2AX (click image for more info)
If you buy a Diono car seat, make sure to register it on their website. Not only will this help you stay in the loop in the event of problems or recalls, but you may also be able to have the car seat replaced if your child was riding in the car seat during a collision.
It's important to replace any car seat that has ever been involved in a collision, even if the collision seems minor and the car seat undamaged. Diono's program is voluntary, and not every one will qualify, but it's a great additional benefit to choosing a car seat from this brand. More details about the program can be found here.
The Diono Rainier 2AX is a great choice in convertible car seats for people with big cars and growing families. It has all the protection and features most parents are looking for, a long life span, and the company may even replace it in the event of a crash. It's a car seat that will protect your child in comfort for many years.
With two kids of my own, I’m passionate about child safety! I’m a research nerd who’s on a mission to make the world a safer place for kids – starting with car seats!
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