Hi there! We're here to help you decide between the CYBEX Sirona S and the Diono Radian 3RXT Safe+.
Our goal is to provide you with the information you need to feel confident that you're choosing the optimal car seat for your family's needs and budget. Let us know if you have any other questions!
At A Glance
CYBEX Sirona S | Diono Radian 3RXT Safe+ | |
Type |
Convertible Rear-Facing Forward-Facing |
Convertible Rear-Facing Forward-Facing High Back Booster Backless Booster |
Current price |
Currently unavailable
-
|
Currently unavailable
-
|
Rating | 4.03 | 4.58 |
Our Thoughts
Comparing the CYBEX Sirona S and Diono Radian 3RXT Safe Plus car seats, it's clear both options offer stand-out safety features. The Sirona S leverages SensorSafe technology for enhanced user alert, while both seats come with reinforced steel frames for increased child security during travel.
The Sirona S's game-changing 360° swivel feature affords parents, especially those with back issues or who frequently park in tight spaces, easier child placement. This car seat also boasts adjustable recline options, creating a comfortable environment as your child grows. However, its complex installation process may frustrate some users, and it's notably bulky, potentially congesting smaller vehicles.
On the other hand, the Diono Radian 3RXT Safe Plus, while lacking the swivable feature, provides parents needing to fit multiple car seats a solution with its slim design. This car seat also offers a 12-position adjustable headrest tailored for growing children's comfort. Nevertheless, installation challenges pertain to both the car seat's assembly and cover reinstallation after washes. And while it's suitable for younger children, it's important to note that at a certain age and height, your child may outgrow this seat.
Looking at each car seat's weight and height specifications, the Diono Radian 3RXT Safe Plus offers Forward-Facing configuration up to a higher height limit (57 inches), which may extend its useful lifespan. However, the CYBEX Sirona S can accommodate a greater weight (up to 65 pounds) compared to the Diono car seat (up to 50 pounds) in the Rear-Facing configuration. This means children can stay in the safer, Rear-Facing configuration for longer.
Given the features and relative trade-offs, if your priority leans heavily towards unique convenience and safety features, the CYBEX Sirona S might be your top pick. Parents that appreciate this model's innovative swivel function and don't mind investing time in learning how to install it properly would benefit most.
However, for the practical-minded parent - especially those needing to fit multiple car seats in one row - the Diono Radian 3RXT Safe Plus presents an excellent choice with its slim design. Despite being less user-friendly in terms of installation and cleaning, its space efficiency and robust safety features may appeal to families with more than one child in a car seat.
Key Details
Sirona S | Radian 3RXT Safe+ | |
![]() |
![]() |
|
Brand | CYBEX | Diono |
Type |
Convertible Rear-Facing Forward-Facing |
Convertible Rear-Facing Forward-Facing High Back Booster Backless Booster |
Weighted Rating | 4.03 | 4.58 |
1 yr Price Range | $439.96 - $549.95 | $259.99 - $349.99 |
Current price |
Currently unavailable
-
|
Currently unavailable
-
|
Value |
![]() Offers advanced features and long-term use from infancy to toddler years, making it a cost-effective option despite its higher price point. |
![]() Offers robust safety features and long-term usability, justifying its price. |
Safety |
![]() Integrated with SensorSafe technology and enhanced side-impact protection, providing top-tier safety for children. |
![]() Steel-reinforced frame and comprehensive protection measures are a standout. |
Features |
![]() The 360° swivel design, magnetic buckle holders, and adjustable recline options set it apart from standard car seats. |
![]() The 12-position headrest and machine-washable cover add notable convenience. |
Installation |
![]() Installation can be challenging, with some parents finding it complex and time-consuming. |
![]() Installation and reassembly, especially of the seat cover, are noted as challenging. |
Cleaning |
![]() The seat cover is removable and machine washable, simplifying the cleaning process. |
![]() The machine-washable cover is practical, but reinstallation can be cumbersome. |
Size |
![]() While it’s not the most compact, its design accommodates growing children, balancing size with comfort and safety. |
![]() Its narrow design is ideal for fitting multiple car seats in a vehicle. |
Review | Click here | Click here |
Comparison of Specifications
While features and reviews provide a sense of real-world use, the specs offer quantifiable details on sizing, limitations, and more. Comparing key measurements and ranges side-by-side is crucial for ensuring you choose a seat properly fitted for your child and vehicle.
We've compiled the weight limits, height limits, dimensions, and other vital statistics for the CYBEX Sirona S and the Diono Radian 3RXT Safe+. This data will confirm whether each seat can accommodate your child's current size and projected growth. Specs like seat depth and width are also important for assessing fit with your car's backseat.
Review the following key measurements for both seats. Pay special attention to the height and weight limits to ensure your child falls within the safe ranges.
Height and Weight Limits
Rear-facing
CYBEX Sirona S | Diono Radian 3RXT Safe+ | |
---|---|---|
Height Range | 17 - 49 inches | 18 - 44 inches |
Weight Range | 4 - 50 pounds | 4 - 50 pounds |
Forward-facing
CYBEX Sirona S | Diono Radian 3RXT Safe+ | |
---|---|---|
Height Range | 28 - 49 inches | 30 - 57 inches |
Weight Range | 22 - 65 pounds | 22 - 65 pounds |
Booster
CYBEX Sirona S | Diono Radian 3RXT Safe+ | |
---|---|---|
Height Range | 40 - 57 inches | |
Weight Range | 40 - 120 pounds |
Dimensions and Weight
CYBEX Sirona S | Diono Radian 3RXT Safe+ | |
---|---|---|
Width | 20.0 inches | 17.0 inches |
Height | 25.5 inches | 28.5 inches |
Depth | 25.3 inches | 16.0 inches |
Weight | 30.4 pounds | 30.6 pounds |
Core Specifications
CYBEX Sirona S | Diono Radian 3RXT Safe+ | |
---|---|---|
Model Year | 2021 | 2018 |
Made In | China | China |
Frame Material | Reinforced Steel | Reinforced Steel |
Safety and Compliance
CYBEX Sirona S | Diono Radian 3RXT Safe+ | |||||||||||||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Federal Safety Standards | Meets all standards | Meets all standards | ||||||||||||||||||||||||||||||||||||||||||||||||||
Configurations FAA-Approved for Airplanes |
Rear-Facing Forward-Facing |
Forward-Facing Rear-Facing High Back Booster Backless Booster |
||||||||||||||||||||||||||||||||||||||||||||||||||
NHTSA Ease-of-Use Ratings |
Rear-Facing Mode
|
Rear-Facing Mode
|
||||||||||||||||||||||||||||||||||||||||||||||||||
Previous Recalls | This car seat has never been recalled. | This car seat has never been recalled. |
Features
CYBEX Sirona S | Diono Radian 3RXT Safe+ | |
---|---|---|
Attachment Methods |
LATCH Seatbelt |
LATCH Seatbelt |
Harness Type | 5-Point | 5-Point |
Cup Holders | Has cup holders. | Has cup holders. |
Warranty and Durability
CYBEX Sirona S | Diono Radian 3RXT Safe+ | |
---|---|---|
Manufacturers Warranty Length | 2 years | 1 year |
Lifespan | 10 Years | 10 Years |
Additional Links
See all CYBEX car seats | See all Diono car seats |
Full review of the CYBEX Sirona S Full review of the Diono Radian 3RXT Safe+ |