2017 Diono Radian RXT Review

2017 Diono Radian RXT Review: The Folding Carseat that’s Great for 3-Across and Extended Rear-Facing

See our review of the updated 2019 Diono 3RXT here

Updated 11-08-18

Recall notice: most Diono convertibles, including the Radian RXT, were recalled in October 2017. See recall details here. 2018 Diono Radian RXT models currently for sale have revised (lower) weight limits and other modifications so this review only applies to RXT models manufactured before the October recall. Updated review is coming soon.

The Diono Radian RXT fills a niche for parents and caregivers looking for a narrow carseat that can hold a big kid. The Radian line of seats is known for being 3-across friendly—when you have a tiny back seat, these are the carseats you generally look at first. The Radian R-series, the R100R120, and Radian RXT, all have basically the same shell design but features distinguish them from each other. Diono discontinued the R100 and R120 in September 2018 and refreshed the carseats in the form of the 3 R and 3RX. This review will focus on the previous version of the RXT, but the information is similar for all the Radians and we have a review of the new 3 RXT forthcoming.

Radian Model

RF Weight Limits

FF Weight Limits

Booster Weight Limits




5-40 lbs.

20-65 lbs.

50-100 lbs.



5-45 lbs.

20-65 lbs.

50-120 lbs.

  • added structural support for higher FF weight limit
  • infant support pillows
  • memory foam under bum

5-45 lbs.

20-65 lbs.

50-120 lbs.

  • added structural support for higher FF weight limit
  • infant support pillows
  • memory foam under bum
  • adjustable head wings
  • shoulder belt guide for booster use is attached to head wings


Radian RXT Weight and Height Limits
  • 5-45 lbs. rear-facing with at least 1.5” of carseat above the child’s head or total height of 44”
  • 20-65* lbs. forward-facing with a child less than 57” tall
  • 50-120 lbs. as a booster with a child 40-57” tall, and child’s shoulders must also be at or above the 4th set of harness slots

*models manufactured prior to 9/5/17 have a forward-facing weight limit of 20-80 lbs.

Radian RXT Overview
  • One of the narrowest convertibles on the market: makes a 3-across much easier!
  • SuperLATCH deluxe push-on connectors
  • 3 crotch/buckle strap positions
  • Safe Stop Load Limiter
  • Full steel reinforced frame and aluminum reinforced sides
  • Folds flat for travel and storage
  • Lined with EPS foam
  • 12-position adjustable headrest
  • 5 harness slot positions
  • Rear-facing tether capability
  • Low profile makes loading and unloading child easier

Radian RXT Measurements:

Harness height: 9”, 10.5”, 12”, 15”, 17.5”
Crotch strap depth: 3.5”, 5.5”, 7”
External widest point: approx. 17” at widest point at shoulders, 16.5” at widest point at thighs
Internal widest point: approx. 14” at widest point at shoulders, 14.5” at widest point at thighs
Seat weight: 26.5 lbs.



Rear-Facing Installation

Installation of the Radian is either easy or hard; there doesn’t seem to be a middle ground with this carseat. In order to install the Radian rear-facing, you must first attach the rear-facing base/boot. That base will set the recline for you automatically—you will not need any rolled towels or noodles to achieve a proper angle. In fact, Diono does not allow the use of rolled towels or noodles with Radians.

For an older child who has good head control and can sit upright unassisted, the Angle Adjuster accessory can be used under a rear-facing Radian to make it more upright and give front seat passengers inches more legroom too.

The RF belt path is a closed belt path, meaning it’s enclosed in plastic. If you’ve got big hands, you’ll have trouble fitting the seat belt or SuperLATCH belt through the belt path; I’ve got average-sized hands and have trouble. Because it’s closed, tightening the belt for a tight installation is difficult too. The best way to get a carseat tight is to pull the belt in the same direction as the belt path, but with a closed belt path, you can’t. You’ll eventually get it tight—it takes you longer to do so.


Forward-facing installation

Installing the Radian forward-facing is easier than RF because the cover can be pulled away for access to the FF belt path. Vehicle buckles that are on short buckle stalks or that are even with the vehicle seat may cause concern because the seat belt will bunch in the latchplate the tighter you pull. This is normal for this carseat.


Special forward-facing concerns:

Adjustable Bottom: When installing the Radian forward-facing, models manufactured after May 2016 require that the forward-facing adjustable bottom be lowered, but only if the child is over 25 lbs. Most forward-facing children will be over 25 lbs., so that means you should lower it before installing the Radian FF. Models manufactured before May 2016 have the option of using it, but it increases your chances of a successful FF install.

Safe Stop Load Limiter: This small strap that is attached to the back left of the carseat when you first receive your Radian is called a load limiter. Its purpose is to increase the amount of time over which your child feels crash forces. If you install the Radian FF for a child who weighs under 40 lbs., you must use the Safe Stop. The Safe Stop is never used rear-facing.


LATCH Installation

The SuperLATCH connectors are the deluxe push-on style connectors, but the connectors are beefier with 4 attachment “pawls” instead of the standard 1 pawl. There is an adjuster on one side of this strap. There are storage areas at the top of the shell to store the LATCH and top tether connectors when not in use. The tether strap can be used rear- or forward-facing. While tethering a forward-facing child restraint with a harness is always recommended, a top tether is not required for this seat.


Weight Limits for SuperLATCH
Radians manufactured before September 2009 48 lbs. or vehicle manufacturer’s limit, whichever is lower
Radians manufactured between September 2009 and March 2014 In vehicles manufactured after 9/1/05: use SuperLATCH to carseat weight limit

In vehicles manufactured before 9/1/05: use SuperLATCH to 48 lbs. or vehicle manufacturer’s limit, whichever is lower

Radians manufactured beginning in March 2014 and newer 35 lbs. rear-facing

40 lbs. forward-facing

Once your child reaches the weight limits for SuperLATCH, switch to the vehicle seat belt for installation, whether rear- or forward-facing.

When the carseat is used as a booster, however, it may be LATCHed in at any weight. This is because the LATCH is simply holding the carseat to the vehicle while the seatbelt is restraining the child and will be the device taking crash forces.

Center LATCH installations with Non-Standard Spacing:

Diono allows LATCH installation in the center seating position if the vehicle manufacturer allows it and the LATCH anchor bars are spaced 11-14” apart.

Inflatable Seat Belts

Diono has determined that the Radian carseats can be installed with inflatable seat belts found in Ford Motor Vehicles. This does not include Mercedes vehicles or inflatable seat belts found on aircraft.

Fit to Child

The Radian RXT comes with an infant head pillow and body support. These items are optional and you can remove them at any time.

The Radian also comes with 2 sets of harness pads: a memory foam-padded set that Velcro around the chest clip and a much longer set that are rubberized on the back with metal slides on the end. The shorter harness pads MUST be used forward-facing for children under 65 lbs. (optional for rear-facing). The longer, rubberized set MUST be used forward-facing for children over 65 lbs.

Because of the well-padded cover and memory foam in the seating area, the Radian is a comfortable carseat. It won’t fit small newborns well, even with the body support, because the bottom harness slots are too high. Most kids make it easily to belt-positioning booster seat age in the harness.

The headrest provides just enough support to be comfy without getting in the way. When the Radian RXT is rear-facing and the child is using either of the bottom 2 harness slots, the headrest must be moved to the top-most position.

When used as a booster, the shoulder belt has a tendency to get caught in the shoulder belt guide. This is more pronounced in older versions of the RXT and Diono has tried to fix this problem in the latest update. It’s a serious problem when the shoulder belt gets caught in the belt guide because if a child leans forward and the shoulder belt doesn’t retract automatically, it stays loose and floppy on the child and could lead to the child being severely injured in a crash. The belt fit and geometry is otherwise very good and even earns it an IIHS Best Bet rating as a booster, but the IIHS doesn’t measure booster fit with real, moving kids.

Cover/Maintenance/Ease of Use

The cover is well-padded with a comfortable texture. Diono recommends hand washing or a front loader washing machine. Definitely hand wash the memory foam! Line dry.

The harness adjuster tightens with a tug-tug-tug motion that may take some getting used to by some caregivers. The harness height adjusts from the back of the seat. Each strap is removed from the metal splitter plate and rethreaded through the correct harness slot. Use the slots at or below the shoulders for rear-facing, above for forward-facing. Children whose shoulders are above the top harness slots, yet still weigh less than the maximum forward-facing harness weight limit, may continue to use the carseat. For those children, the tops of their ears must be below the top of the carseat.

FAA-Approval/Lifespan/Crash Guidelines

The RXT is FAA-approved for use in aircraft. It also is a heavy restraint weighing in at 26.5 lbs., so if you do travel with it, you’ll want to use a luggage cart to avoid having to carry it. The RXT does come with a padded shoulder strap for carrying and I suggest buying another to be able to carry it backpack-style if you intend to carry it. Since the Radian seats are some of the narrowest on the market, you won’t have any problems fitting one in a plane seat AND the tray table will be able to come all the way down for a forward-facer. For rear-facing, the Angle Adjuster may make the seat fit depending on the pitch of the seats on the plane your flying. Buying a snack for the person in front of the carseat certainly doesn’t hurt ;). Remember that it can only be used with the harness on the plane since belt-positioning booster seats can’t be used on planes.

Radians manufactured before May 2016 have expiration dates of 8 years as harnessed seats, 10 years as belt-positioning boosters. Radians manufactured as of May 2016 and newer have 10 year expirations from date of purchase (or DOM if you didn’t save your receipt).

Diono recommends replacement after any crash.

  • 3 Crotch Strap Positions: Having a choice of crotch strap positions makes the harness more comfortable for bigger kids.
  • Low and narrow footprint means it’s more likely to fit in tight spots.
  • Padded Cover: A thickly padded cover, plus the memory foam in the bum area, makes for a comfy seat.
  • Folds flat for travel and storage
  • Low profile makes loading and unloading child easier
  • Can be installed with Ford Motor Company inflatable seat belts

(In all fairness, these aren’t necessarily problems but I list them here to inform potential consumers of specific Radian RXT issues)

  • Low LATCH weight limits
  • Harness Adjuster: It’s tug-tug-tug can be frustrating for some used to a smooth adjuster on an infant seat.
  • Installation: Often more difficult depending on the vehicle, with a higher learning curve due to the various features.
  • Snug fit of the shoulder belt in booster mode is poor; shoulder belt can get caught leaving slack.
  • Heavy for a carseat designed for travel

The Diono Radian RXT is a solid convertible seat with great rear-facing features. Its high height and weight limits accommodate big kids both rear- and forward-facing, yet it takes up less space than many of its competitors. For narrow backseats or 3-across situations, you simply can’t beat the width of the RXT. Features like rear-facing tethering, thick padding, and solid construction make the Radian RXT a solid purchase.


Thank you to Diono for supplying the RXT used in this review!


  1. Christa Jones August 11, 2019
    • SafeDad August 11, 2019
  2. Barb Chars March 31, 2019
  3. Sarah October 9, 2018
    • Heather October 10, 2018
  4. Chelsea September 26, 2018
    • Heather September 26, 2018
  5. Mikayla September 23, 2018
    • Heather September 23, 2018
  6. Leah August 15, 2018
    • Kecia August 15, 2018
    • Heather August 15, 2018
  7. Kristine June 12, 2018
    • Heather June 12, 2018
  8. Kathie June 3, 2018
    • Heather June 12, 2018
  9. Keith November 25, 2017
    • Heather December 6, 2017
  10. Kara Reimer September 18, 2017
    • Heather September 23, 2017
  11. Tiffany September 11, 2017
    • Heather September 18, 2017
  12. Danielle August 9, 2017
    • Danielle August 9, 2017
    • Heather August 10, 2017
  13. Fiona June 29, 2017
    • Heather June 29, 2017