| Mode | Weight | Height |
|---|---|---|
| Rear-facing harness | 4–50 lb | 18–44 in |
| Forward-facing harness | 22–65 lb | 30–57 in |
| Belt-positioning booster | 40–120 lb | 40–57 in |
- Seat weight
- Not published
- Width
- Not published
- Usable life
- 10 years
- Aircraft
- Certified
Diono does not sell this seat on Amazon. See its own site for photos.
Listed as discontinued
Diono Radian 3RX All-in-One Convertible Car Seat
An all-in-one car seat with 3 modes: rear-facing harness 5 to 50 lb, 18 to 44 in; forward-facing harness 22 to 65 lb, 30 to 57 in; belt-positioning booster 40 to 120 lb, 40 to 57 in.
At a glance
- Fits children from 5 to 120 lb
- Up to 57 in tall
- 3 modes: rear-facing harness, forward-facing harness, belt-positioning booster
- 10-year usable life
- Certified for aircraft use
Not sold on Amazon
Diono lists this seat on its US site. Buy from Diono or an authorized retailer, and confirm the exact model number before you buy.
Who is the Radian 3RX All-in-One Convertible Car Seat for?
The Radian 3RX is an all-in-one car seat that Diono's support center dates 2021 to 2023. Its manual lists rear-facing from 5 to 50 lb and 18 to 44 in, a forward-facing harness from 22 to 65 lb and 30 to 57 in, and booster mode from 40 to 120 lb. Do not use it over ten years from purchase.
Reasons to consider it
- Rear-facing up to 50 lb or 44 in
- Includes a rear-facing top tether connecting strap
- Harness modes certified for aircraft
- An infant head and body support cushion for smaller babies
Things to weigh up
- Listed by Diono as a 2021 to 2023 model
- Do not use over ten years from the date of purchase
- LATCH ends at 35 lb rear-facing and 40 lb forward-facing
- Diono lists the seat at 25.9 lb
My take on the Radian 3RX All-in-One Convertible Car Seat
The 3RX is mainly relevant if you already own one or are offered one, since Diono dates it 2021 to 2023. Check the purchase date against the ten-year limit and confirm the manual and parts are present. Its limits match the Radian 3RXT manual, and both start forward-facing at 22 lb, lower than the 26.5 lb in the current Radian 3R manual.
A research summary of Diono’s published specifications and manual, read . Not a hands-on test or a crash-safety rating.
Who the Radian 3RX All-in-One Convertible Car Seat fits
This seat covers 3 stages, and a child has to meet every limit of the stage they are in. Diono gives it a 10-year life from the date of manufacture, so check the date label before using a hand-me-down.
- Rear-facing harness5 to 50 lb · 18 to 44 in
- The child faces the back of the car, which keeps the head, neck and spine supported in a frontal crash. Keep this mode as long as the child fits it.
- Forward-facing harness22 to 65 lb · 30 to 57 in
- The child faces forward in the seat’s own harness. Use the top tether every time, and stay in the harness until the child outgrows it.
- Belt-positioning booster40 to 120 lb · 40 to 57 in
- The seat raises the child so the vehicle’s own lap and shoulder belt sits on the hips and across the shoulder. The child has to sit properly for the whole ride.
What are the Radian 3RX All-in-One Convertible Car Seat weight, height and age limits?
| Mode | Child weight | Child height | Minimum age | Conditions |
|---|---|---|---|---|
| Rear-facing harness | 5 to 50 lb | 18 to 44 in | Not published | LATCH installation limited to 35 lb |
| Forward-facing harness | 22 to 65 lb | 30 to 57 in | Not published | 22-30 lb must use the middle buckle slot |
| Belt-positioning booster | 40 to 120 lb | 40 to 57 in | Not published | — |
A child must meet every limit for the mode they use. The labels on your seat and its manual are the final word.
Radian 3RX All-in-One Convertible Car Seat specifications
- Seat weight
- Not published
- Width
- Not published
- Usable life
- 10 years
- Aircraft use
- Certified for aircraft (see manual for which modes)
Will it fit your car?
Diono does not publish a width for this seat, so measure your back seat and compare it with the seat in a store before buying.
- Check your vehicle manual for lower anchor positions and any head-restraint rules.
- Rear-facing seats need front-seat room: try the install behind the driver before you commit.
- Certified for aircraft use, so it can travel as a seat rather than checked baggage.
What to know before you live with it
Rear-facing with the base and tether strap
Rear-facing covers 5 to 50 lb and 18 to 44 in. LATCH is limited to 35 lb, after which the manual says to reinstall with the vehicle belt for 35 to 50 lb. The manual says to always use the rear-facing base on rear-facing installs, and never the adjustable bottom. The recline level indicator shows an infant range of 5 to 22 lb and a toddler range from 40 lb. The seat includes a rear-facing top tether connecting strap that wraps around a vehicle seat track bolted to the frame, with a metal D ring as the anchor. The manual says to use it only rear-facing and to check the vehicle manual.
Source: Diono Radian 3RX manual (PDF)
Forward-facing from 22 lb
The forward-facing harness runs from 22 to 65 lb and 30 to 57 in. The manual says not to turn a child forward until at least one year old and 22 lb, and Diono recommends rear-facing until at least two. Always use the top tether. Lower the adjustable bottom once the child is over 25 lb. The SafeStop is used from 22 to 40 lb and removed at 40 lb. LATCH is allowed to 40 lb, then the lap/shoulder belt. Children from 22 to 30 lb use the middle buckle slot and above 30 lb the forward-most slot. A lap belt with no tether needs the lap belt cushion.
Source: Diono Radian 3RX manual (PDF)
Headrest, booster mode and washing
When the child fits the third harness slot, the headrest may be used at its lowest position. To move it, unfasten the fabric panels, tilt the top of the headrest toward you and slide it. Booster mode covers 40 to 120 lb with the harness removed and only the vehicle lap/shoulder belt, never a lap belt alone. For washing, remove the foam insert from the seat pad and do not wash the foam. Fabrics go in cold water on a gentle cycle and dry flat in the shade, with no bleach, iron or dry cleaning.
Source: Diono Radian 3RX manual (PDF)
Is the Radian 3RX All-in-One Convertible Car Seat recalled?
- 17C003000: does not cover this model. The Part 573 report for campaign 17C003000 lists six models only: Radian R100 (model no. 16600 or 16000), Radian R120 (16800 or 16000), Radian RXT (16900 or 16000), Olympia (30100), Pacifica (30400 or 300000) and Rainier (30300 or 300000), built between November 25, 2013 and September 5, 2017. The Radian 3RX is a separately named Radian 3 series seat and is not among the listed models. Campaign source (read ).
Each campaign naming this family was read against this model’s numbers and build dates, and none covers it. Still check your seat’s model number and date of manufacture before use, especially on a used seat.
Radian 3RX All-in-One Convertible Car Seat: common questions
What are the Radian 3RX weight and height limits?
Rear-facing is 5 to 50 lb and 18 to 44 in, the forward-facing harness is 22 to 65 lb and 30 to 57 in, and booster mode is 40 to 120 lb. The seat is designed for children 5 to 120 lb.
How long can I use a Radian 3RX?
The manual says not to use it once it is over ten years from the date of purchase. It also says not to use it with damaged or missing parts, missing instructions, or cut or frayed straps.
Is the Radian 3RX approved for airplanes?
The manual certifies it for aircraft in harness mode, installed with the lap belt instructions. It is not certified in booster mode because aircraft seats have no shoulder belt.
What is the difference between the Radian 3RX and 3RXT?
The Radian 3RXT is listed with rear-facing at 5 to 50 lb, forward-facing at 22 to 65 lb and booster mode at 40 to 120 lb, the same as the 3RX manual. Neither manual publishes a feature comparison between the two.
How wide is the Radian 3RX?
Diono lists it at 17 in wide, 16 in deep and 28.5 in tall, with a seat weight of 25.9 lb.
Will three Radian 3RX seats fit across?
Diono says a vehicle needs at least 51 in of seat width between the door handles to fit three of its all-in-one models.
Answers refer to the model and manual version on this page. Check the instructions supplied with your seat.
Before you buy
- Weigh and measure your child. The limits above are the manufacturer’s, and a child has to meet all of them for the mode they will use.
- Confirm the exact version. Colors, retail exclusives and model numbers change limits more often than you would expect.
- Read the manual before you buy, not after. It is linked above and holds the fit rules, the install methods and the expiry.
- Check recalls by model number and date of manufacture, and register the seat with Diono so you hear about the next one.
Sources
Other Diono convertible car seats
| Model | Top child weight | Seat weight | Width | Usable life |
|---|---|---|---|---|
| Radian 3RX All-in-One Convertible Car Seat (this seat) | 120 lb | — | — | 10 years |
| Radian 3QX SafePlus All-in-One Convertible Car Seat | 120 lb | — | — | 10 years |
| Radian 3QXT SafePlus All-in-One Convertible Car Seat | 120 lb | — | — | 10 years |
| Radian 3QXT FirstClass SafePlus (Radian 3QXT+) All-in-One Convertible Car Seat | 120 lb | — | — | 10 years |
| Radian 3R SafePlus All-in-One Convertible Car Seat | 120 lb | — | — | 10 years |
| Radian 3RXT SafePlus All-in-One Convertible Car Seat | 120 lb | — | — | 10 years |
| Radian 3RXT SafePlus Max All-in-One Convertible Car Seat | 120 lb | — | — | 10 years |
| Radian 3R All-in-One Convertible Car Seat | 120 lb | — | — | 10 years |
| Radian 3RXT All-in-One Convertible Car Seat | 120 lb | — | — | 10 years |