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Diono Radian 3RXT Review

The Radian 3RXT is an updated version to the original Radian RXT. The Radian 3RXT is an all-in-one convertible car seat, which means it is intended to grow with your child. In this detailed review, we look into recalls, warranty, top features, pricing, and much more. 

About The Brand

Diono is a car seat brand that is known for safety, durability, and sleek and modern design. As the brand has grown on the market, it has become known as one of the best car seat brands for parents who value both safety and aesthetics. Diono has become known as one of the few luxury car seat manufacturers on the market today. 

There are a lot of things to love about the Radian line from Diono when it comes to car seats.  

Radian 3RXT Overview

There are a lot of convertible car seats on the market, but very few of those models are able to achieve the highest of standards in all of the desired areas of a car seat. The Radian 3RXT is able to achieve greatness in most, if not all of the areas that a convertible car seat should be expected to achieve. 

One of the aspects of the Radian 3RXT that distinguishes it from the other elite car seats on the market is that it is designed to be incredibly narrow. This is why many parents who have three or more children look for the Radian 3RXT in order to safely accommodate three car seats in one row of a small vehicle.

Steel Frame 

Steel Frame of Car SeatThe Radian 3RXT is built of a steel frame and is extremely durable. After all, if you are purchasing a car seat that is designed to work from birth to twelve years old, you expect it to hold up. It has a high-quality fabric covering the frame and comes in a variety of colors. 

Because this seat is built of a steel frame, it is really heavy when compared to other convertible car seats. It weighs in at a whopping 25 lbs. This could definitely be a con for the seat if you have to move your car seat between cars often. 

Unlike a lot of the lower budget car seats, the Diono Radian 3RXT has a durable cloth covering for the rear of the seat. A lot of parents rave that this feature helps to keep all the straps and belts organized. On the other hand, some parents feel that this particular feature makes the installation of this car seat more complicated than it should be. 

Designed For Comfort 

This seat is also designed with comfort and convenience in mind. This seat is built for the comfort of your child from birth to booster. However, it is also approved to fly on airplanes and folds up for the convenience of carrying or transporting it. There are so few car seats on the market that are able to add to the convenience of the parent like this. 

What we Like

  • Modern Style
  • Narrow Build
  • Safety Features
  • Durability

What We Do Not Like

  • Heavy Seat
  • Complicated Instillation 
  • Seat Back Cover Complicates Things

Height & Weight Limits

With a convertible seat like the Radian 3RXT, the seat is built to last from your child’s birth until they no longer need a booster seat. While the Radian 3RXT is perfectly safe for a newborn, most parents choose to go with an infant carrier for the first 9 months of a baby’s life. However, if you want you can start your infant out in the radian 3RXT from the day you bring baby home from the hospital. 

The weight and height requirements for this seat are comparable to other convertible options on the current market. 

Rear Facing 5-45 LBS / Up to 44 Inches

Forward Facing 20-65 LBS / Up to 57 Inches

Booster 50-120 LBS / Varies 

While this chart is comparable to other seats, it is actually one of the major weaknesses for this Diono car seat. Children may outgrow the height limits well before they are nearing the height limit based on weight. This may be attributed to the narrow design of the seat. Regardless, it is an area of complaint for some Diono customers. 

How Safe is It?

Diono has a reputation for being one of the safest car seat manufacturers on the market today. If you do a quick internet search you can find piles on piles of testimonials from parents who have experienced the safety of a Diono car seat first hand. There are several design considerations that might play a part in why these seats do such a great job during a crash. 

The Diono Radian 3RXT features additional support for side-impact. This is reminiscent of the newborn insert that you may remember using when your child was a tiny baby. This additional support provides extra cushioning to protect your child’s head from any impact that sends their head to either side. 

Another unique feature that is patented only to Diono car seats is the super latch system. The Radian 3RXT utilizes this patented technology which affects the safety of the lower anchor connector. Instead of the normal loop that you see on most car seats, the Diono Radian 3RXT has four “teeth” that make the anchor much stronger than your average car seat. 

The Diono Radian 3RXT also has a considerably higher weight limit of 45 lbs for rear facing children. There has been a lot of research about how rear facing car seats are far more safe in a crash than forward facing seats. So, parents love to find a seat that allows them to safely rear face their children for a longer period of time. 

Lastly, we have already mentioned that this seat is constructed of a steel frame. However, it is important to mention that the durability of a seat directly affects the seat’s safety. There is no question that this is one of the safer options on the market. 

Ease of Installation

One of the major downsides to this seat is that installing it is actually incredibly confusing. Some parents even complain that the manual is less than helpful providing vague references to latches and adding to the confusion of the seat. 

The good news is that once you have properly installed the seat adjustments made at a later date will be easier to understand. You also have a really solid and safe seat once it is properly installed and ready to go. You can find an installation video on the Diono website which is incredibly helpful to watch as you begin to install your new car seat. 

The biggest inconvenience with this seat is that you have to completely remove the seat and rethread all of the straps in order to adjust the straps to your baby’s height. Babies tend to grow pretty quickly and this is really inconvenient, especially for parents who have had the luxury of an easy-adjust seat in the past. 

Ease of Cleaning

This is another area where the Diono Radian 3RXT is really beating out all of the other brands. The covers of this car seat are machine washable. Any parent who has a child who experiences motion sickness understands how much of a relief this can be. This seat is one of the easiest of all to clean. 

Everyday cleaning is also fairly easy, although cleaning underneath the seat cover, or underneath the seat, itself might be a little tricky. As mentioned before, installing and uninstalling the seat is a bit complicated the first few times you try to tackle the task of installation. 

Overall, this seat is really easy to clean. There is nothing easier than a machine-washable car seat cover. It also comes in a variety of color options which makes the choice for choosing a darker color to hide stains easier for the parent. 


Another thing is that the seat consumes very little space when you have to store it. You can just fold it flat and shove it into any corner. With other products, you will not get this benefit and they are really hard to store.

Prior Recalls

There are no recalls to the Radian 3RXT at this time. Some Radian car seats (original models 2013-2017) were recalled due to an issue when installing the seat with only the lap seat belt. 


Diono offers a limited one-year warranty on physical defects that are a result of up to one year of regular use. Essentially, if the seat is not working properly after only one year of use, they will replace the seat on their dime. 

You will need to make sure that you keep track of your receipt in order to cash in on a warranty claim. The Diono brand requires proof of purchase in order to make a claim to warranty on their website. 

The Final Verdict

This is a fantastic convertible car seat for anyone who is on the market for a luxury seat for their little one. The safety features, modern design, and longevity of this seat far outweigh the downfalls to choosing Diono. 

For a parent who is looking to seat three kids to one row, you really cannot go wrong with the Radian 3RXT. Even with the downfalls, safety alone is well worth the price. Overall, I would give this seat a nine out of ten which is pretty close to perfect.