Hi there! We're here to help you decide between the CYBEX Sirona S and the Diono Radian 3R.
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 3R | |
Type |
Convertible Rear-Facing Forward-Facing |
Convertible Rear-Facing Forward-Facing High Back Booster |
Current price |
Currently unavailable
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Currently unavailable
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Rating | 4.03 | 4.70 |
Our Thoughts
As a parent, car seat safety is undoubtedly a top concern. Right now, we're comparing two popular products on the market. On one hand, we have the CYBEX Sirona S - a versatile convertible car seat loved for its 360° swivel feature and enhanced safety technology. On the other hand, the Diono Radian 3R, with its slim design and steel frame construction, offers multiple seating options and a space-saving design.
The Cybex Sirona S is a convertible car seat designed for both rear and forward-facing use, accommodating children up to 65 pounds in the forward-facing position. It shines with its SensorSafe technology that alerts parents to potential unsafe situations. Its innovative 360° swivel design adds a layer of convenience—especially helpful for parents with troublesome back issues or confined parking situations. However, the increased complexity of the design does cause some parents to find the installation process challenging. The cover is also removable and machine washable, simplifying the cleaning process. The Cybex Sirona S is a bit bulky and might be a tight fit for petite vehicles, but the overall benefits in terms of safety and convenience make it a high-value choice for growing families.
In contrast, the Diono Radian 3R stands out for its slim design, permitting three-across seating in most vehicles. This is a major advantage for families with multiple children who still want to maximize backseat space. The Diono Radian 3R offers an impressive array of seating configurations: rear-facing up to 40 pounds, forward-facing up to 65 pounds, and even as a high-back booster up to 100 pounds. However, it should be noted that some parents expressed concerns about the lack of head support which becomes increasingly significant in booster mode. Additionally, while the seat cover is removable, some parents reported challenges in its maintenance and durability. Furthermore, the Radian 3R is also remarkably heavy, complicating its use for frequent vehicle swapping.
Considering these aspects, if superior safety is your main preference and your budget allows for it, the CYBEX Sirona S could be an exceptional fit for you, offering advanced safety features such as side-impact protection, SensorSafe technology, and a versatile swivel function for comfort and accessibility. However, if your top priority is outfitting a smaller vehicle with multiple seats, the slim yet robust Diono Radian 3R, with its long lifespan and diverse seating modes might be the better option. Overall, both seats present unique advantages depending on specific needs.
Key Details
Sirona S | Radian 3R | |
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Brand | CYBEX | Diono |
Type |
Convertible Rear-Facing Forward-Facing |
Convertible Rear-Facing Forward-Facing High Back Booster |
Weighted Rating | 4.03 | 4.70 |
1 yr Price Range | $439.96 - $549.95 | $155.39 - $199.98 |
Current price |
Currently unavailable
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Currently unavailable
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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 a long lifespan and versatile seating options, making it a cost-effective choice over time. |
Safety |
![]() Integrated with SensorSafe technology and enhanced side-impact protection, providing top-tier safety for children. |
![]() Features a steel frame for enhanced safety and reliability, scoring high in safety ratings. |
Features |
![]() The 360° swivel design, magnetic buckle holders, and adjustable recline options set it apart from standard car seats. |
![]() Despite its minimalist design, it includes essential features like memory foam padding and a foldable design for travel (converts into a backpack!) |
Installation |
![]() Installation can be challenging, with some parents finding it complex and time-consuming. |
![]() Installation experiences vary; some find it straightforward, while others face challenges, especially in smaller vehicles. |
Cleaning |
![]() The seat cover is removable and machine washable, simplifying the cleaning process. |
![]() The seat cover is removable for cleaning, but some users report challenges in maintenance and durability. |
Size |
![]() While it’s not the most compact, its design accommodates growing children, balancing size with comfort and safety. |
![]() Its slim profile is a standout feature, allowing for three-across seating in most cars. |
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 3R. 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 3R | |
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Height Range | 17 - 49 inches | 0 - 44 inches |
Weight Range | 4 - 50 pounds | 5 - 40 pounds |
Forward-facing
CYBEX Sirona S | Diono Radian 3R | |
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Height Range | 28 - 49 inches | 0 - 57 inches |
Weight Range | 22 - 65 pounds | 20 - 65 pounds |
Booster
CYBEX Sirona S | Diono Radian 3R | |
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Height Range | 0 - 57 inches | |
Weight Range | 50 - 100 pounds |
Dimensions and Weight
CYBEX Sirona S | Diono Radian 3R | |
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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 | 25.9 pounds |
Core Specifications
CYBEX Sirona S | Diono Radian 3R | |
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Model Year | 2021 | 2018 |
Made In | China | China |
Frame Material | Reinforced Steel | Reinforced Steel |
Safety and Compliance
CYBEX Sirona S | Diono Radian 3R | |||||||||||||||||||||||||||||||||||||||||||||||||||
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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 |
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NHTSA Ease-of-Use Ratings |
Rear-Facing Mode
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Rear-Facing Mode
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Previous Recalls | This car seat has never been recalled. | This car seat has never been recalled. |
Features
CYBEX Sirona S | Diono Radian 3R | |
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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 3R | |
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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 3R |