Diono: RadianRXT Convertible Car Seat Review


We recently had the opportunity to review the RadianRXT Convertible Car Seat by Diono (formerly Sunshine Kids). The RadianRXT is a versatile car seat that seats rear-facing children from 2,3-20,5 kg (5-45 lbs), forward-facing children from 10-29,5 kg (22-65 lbs) in 5-point harness, then converts to a booster for children up to 54 kg (120 lbs).

This convertible car seat is solid and built with a steel alloy frame, rainforced sidewalls and a SafeStop energy absorbing harness. The RadianRXT has been NCAP crash tested and rated for UAS use with a child up to 29,5 kg (65 lbs).


What you get in the box:

RadianRXT Convertible Car Seat, one cup holder (option to add up to 4 cupholders), rear-facing base, infant support cushions, SafeStop harness, rear-facing tether connector strap, and instruction manual.

Main Features:

  • Steel alloy frame and aluminum reinforced sides
  • Safestop energy-absorbing harness system
  • Adjustable head support, reinforced for complete side impact safety
  • Energy-absorbing EPS foam panels on all sides
  • Rear-facing tether capability
  • UAS installation up to 29,5 kg (65 lb) child
  • Infant body support cushions
  • Memory foam padding for superior comfort
  • 5 shoulder and 3 buckle positions for custom fit
  • Expandable sides and longer seat bottom for leg support and comfort
  • 12 height positions for adjustable head support
  • 2 recline positions in forward-facing mode
  • Sits low on vehicle seat for easy child boarding
  • Fits 3 across in a mid-size vehicle and offers more shoulder space
  • Add up to 4 cup holders (1 included)
  • Folds flat for travel and storage
  • Rubber bottom grips for no-slip installation
  • 10 year life
  • One-year limited warranty
  • Price: $359.99


I found the installation process standard to what I have experienced with other convertible car seats. For rear-facing installation you can use either the SuperLATCH system or the vehicle’s seatbelt.  When rear-facing the RadianRXT installs with the base that’s included. The recline angle is wonderful for infants without head control and it’s also o.k. for older rear-facing children. Our almost 3 year-old was very comfortable rear-facing.

 photo Diono-RadianRXTConvertibleCarSeatrear-facing_

The Radian RXT features a tether system that is required for forward-facing. I installed the car seat successfully and achieved a good position. The nice open belt path that’s behind the cover of the seat allows for easy access to the seatbelt or the SuperLATCH straps to adjust.  The instructions for installation were pretty clear and it was easy to switch back to rear-facing afterwards.

 photo Diono-RadianRXTConvertibleCarSeatforwardfacing

I appreciate that the RadianRXT has one of the highest rear-facing weight limit on the market (45 pounds!). My almost 3-year-old is still rear facing and I fully support keeping children rear-facing as long as possible.



The RadianRXT  features a 5-point-harness from 5-80lbs! It has five different shoulder-height adjustments and three different buckle adjustments. The harness height can be adjusted at the back of the seat and you can easily adjust the harness at or below the shoulders for rear-facing children and above for forward-facing.

The crotch strap and width of the seating area can be adjusted depending on the size of your child.


The RadianRXT has a heavy steel alloy frame and aluminum reinforced sides. It also features EPS energy-absorbing foam and a Safe-Stop load limiting device that can be installed at the back of the seat when front-facing. The Safe-Stop attachment should absorb some of the force of a crash in case of accident.

I really appreciate the high safety ratings of this car seat and the fact that crash test videos and results are available on their site.

 photo Diono-RadianRXTConvertibleCarSeatsafe

Covers and Padding:

We received the “Storm” cover to try, a grey cover with black accents. Covers can be removed and you can hand wash them or wash them on a front loader washing machine. You can also purchase new covers if needed and there’s a variety of fabrics and colours available.

I really like that the “Storm” cover we received is BFR-free. It means that the fabric is inherently flame-resistant and not treated with any flame retardants at any point in the manufacturing process.

Other Features:

Something else I like about the RadianRXT is that the car seat folds flat, great for traveling or storage. You can even purchase a special carry strap that allows you to wear the carseat like a backpack! Awesome right?  The car seat is heavy (24lbs) but still, I love having the option.

The RadianRXT is also one of the slimmest and least-bulky car seats available on the market. It means that you can actually fit three of these across the backseats of most vehicles. Not bad for families with several young children.

In general I really like the RadianRXT convertible car seat. I like that you can use it from birth until 120lbs, making it the only seat you need to purchase for your child.  The safety ratings are also pretty high and the seat seems comfortable and it is easy to install. I really like that we can continue rear-facing up to 45lbs as well!

Disclosure: I received a sample of a product to facilitate this post. All views and opinions stated on this post are 100% my own.

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Angela V

Founder and Writer at One Smiley Monkey blog
Hi, my name is Angela van Tijn and I live in Vancouver, Canada with my wonderful husband, our two boys and our puppy. I am the founder and primary contributor behind One Smiley Monkey. Welcome to my blog!

16 responses to “Diono: RadianRXT Convertible Car Seat Review”

  1. We are shopping for a convertible car seat so I am very interested in the Diono. Thanks for the informative review, I like the rear-facing up to 45lbs feature.

  2. Awesome detailed review! Good car seats are so hard to find. We will certainly check this one out at the store when our current car seat expires.

  3. Great review! Love the photos!:)

  4. We love Diono products in our family! Thanks for a really informative review!

  5. it’s always important to properly install your child seat!

  6. I like that this carseat is relatively lightweight and compact but that it can hold a child up to 120 lbs!

  7. I love the safety and ability to grow with it. This would be a dream for disabled children too.

  8. Love your review of this carseat it is so versatile and has a very high safety rating too!

  9. Looks like a great car seat. We are on the market for a big boy car seat and we’ll have to look into this one. Thanks!

  10. Love to have one!

  11. This looks and sounds like a great seat. I love the fact that you are able to fit 3 seats side by side in most cars, we are currently in the market for new seats for our 2 children so I will most definitely be considering this one. Thank you!

  12. 3 of our 4 seats are Radian RXTs. In addition to the features here, I like that if I put the car seats next to each other in the back, a full-grown adult can still fit back there next to them (in my CRV). I fit and I’m plus-sized. I also like the recline-adjuster pad that Diono sells. It allows us to still install the seat RF in my MIL’s car. Otherwise I’d have to allow my daughter FF in her car, and mess with moving the straps to different slots. That’s the one thing I don’t like – I would prefer if the harness was of the no-re-thread variety.

  13. Good morning! Thanks for the explanation! Its very good!

    I have a question regarding RXT car seat…. I have a mid-size car (Honda City, year 2012), and I’ve read in some blogs that this car seat is suitable for SUV or VAN. Could anyone tell me if it fits in my car?
    Thank You!

    • Hi Susan, I haven’t installed the RadianRXT in any other cars but this is one of the least bulky options and I am sure it would be o.k. in a mid-size car. I would recommend you get the foam adjuster that would give you some extra space between the front seats when rear-facing.

      Also, see if you can test it with your vehicle at a store before buying, just to make sure it fits o.k.

    • City is a compact, not mid sized. You think a civic is full sized then I guess. Lol. It will fit fine in a city, I have put one into a versa without any issues. The compact cars now keep the front seats pretty vertical for more rear space.

  14. Thanks so much for this amazing review! I haven’t seen the issue you wrote about the head wings and the seatbelt mentioned anywhere else, so I’m glad I found your review. I’m wondering if the R120 would have the same issue, since there are no head wings?

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