The Diono RadianRXT is meant to take children from infancy through childhood. A 3-in-1 design transforms the Radian from a rear-facing seat to a front-facing seat to a belt-positioning booster, and the height and weight limits are the most generous on the market. The narrow profile also makes it a good pick for cramped backseats, but beware: The seat can be a space hog front-to-back when installed rear-facing.
Safe, without the bulk of other seats. The Diono RadianRXT is a more recent seat that has not been independently crash tested. However, prior Diono seats have earned good scores. Diono also publishes its own crash-test results on its website. The seats are able to maintain a narrow 17-inch base because the frame is made with steel for greater rigidity in a crash. The seat's side-impact protection is bolstered with aluminum rather than plastic, which reduces bulk without sacrificing strength. The seat also offers side-wing head protection to keep children's heads from moving in a crash, and it can be tethered for greater stability both rear- and forward-facing. Like all convertible car seats, the RadianRXT also has a five-point harness with a chest clip.
Straps can be tricky to tighten. The Diono RadianRXT offers high-end convenience features like push-button LATCH connectors that anchor the seat to the car, but parents complain about a more challenging installation. The seat has a lower center of gravity overall and a relatively narrow path for anchoring the tethers or the seat belt, and some owners complain that this makes it difficult to route the straps and tighten them, particularly in the rear-facing position. The seat lacks a no-rethread harness-height adjuster, but the harness tension is adjustable from the front. The cover is machine washable, but the harness has to be unthreaded to remove it. The National Highway Traffic Safety Administration (NHTSA) gives the seat only 2 out of 5 stars for overall ease of use, criticizing labeling, unclear forward-facing instructions and tricky conversions between rear-facing, forward-facing and booster use.
Seat is narrow but tall. The Diono RadianRXT is compact enough to fit three across in the backseat, an important consideration for families with three children who all need to be in a car seat. However, the seat has a fairly high back that can demand a lot of front-to-back room when it is installed rear-facing. Diono sells an angle adjuster (Est. $12) that parents say does an effective job of alleviating this problem, but Diono cautions against its use until children have full head control and can sit unassisted. The seat has soft foam padding that keeps kids comfortable and absorbs impact, but it doesn't have armrests. It comes with removable padding for better infant positioning. The seat folds up for easier traveling, but at 23 pounds, it might not be worth it. The RadianRXT's high height and weight limits make this a good pick for extended rear-facing use and taller children in general: The seat accommodates kids up to 44 inches and 45 pounds rear-facing and 57 inches and 80 pounds forward-facing. Another big bonus: The seat can then convert to a booster for use up to 120 pounds.
Usable for up to a decade. Most reviewers give Diono high marks for customer service, and the Diono website is full of information about its seats' safety. The company markets the RadianRXT as a long-term car-seat solution for children and boasts an industry-best usable life span of 10 years (used with a harness, the seat has an eight-year expiration; booster use adds an additional two years). Like most car seats, the RadianRXT has a limited one-year warranty. It also has an unusual crash exchange program. If you are in an accident with your child in the car seat, the company will send you a new seat in exchange for being able to examine the affected seat. There are limitations, and it's at the company's discretion.
Our Sources: Diono Radian Car Seat Reviews
1. Baby Bargains
"Baby Bargains" covers the Diono line in general and the RadianRXT specifically. Authors Denise and Alan Fields consider performance, ease of use and the brand's track record to come up with their overall rating.
Review: Car Seats: Picking the Right Child Safety Seat, Denise and Alan Fields, Tenth Edition, 2013
Murphy describes the features in Diono's new generation of convertible 3-in-1 car seats, including the RadianRXT. This highly detailed review includes pictures of key details and a pros-and-cons list. The seat also makes the site's list of recommended car seats.
Review: Diono Radian RXT Convertible Review: A New Generation, Heather Murphy, Nov. 2, 2011
The RadianRXT receives 4.5 out of 5 stars based on more than 500 reviews. Users love that they can fit three of these seats in the backseat. They also comment on the tricky installation, and some complain that the straps are hard to tighten.
Review: Diono RadianRXT Convertible Car Seat, Contributors to Amazon.com, As of September 2013
The RadianRXT is part of this roundup of best car seats for 2012. Horton praises the RXT's long life span, safety features and ability to fold flat for travel. She also likes how narrow the seat is. However, it's not the best for small babies, she says.
Review: Babble Blogger Favorites: Infant and Toddler Car Seats, Michelle Horton, Nov. 12, 2012
5. National Highway Traffic Safety Administration
The RadianRXT receives 3 out of 5 stars forward-facing and 2 stars rear-facing for overall ease of use in the NHTSA's tests. The labels are particularly lacking and converting the seat between rear-facing, forward-facing and booster use is difficult, testers say.
Review: Child Safety Seat Ease of Use Ratings, Editors of National Highway Traffic Safety Administration, As of September 2013