Diono Rainier Review

The Diono Rainier is a beast of a car seat. Because it is built to accommodate both extended rear-facing (to 50lbs) and extended five-point harness forward-facing (to 90lbs), it is significantly taller than many other car seats on the market. Because of that, this seat is a major front seat legroom hog in rear-facing mode. But… it is super safe, newborn compatible, easy to install, and folds up for easy(ish) portability. So pluses and minuses. And those minuses are less important if you're already living that SUV/minivan life.

Things We Love

Good Looks for a Baby Throne: The Diono Rainier has a modern fabric and look to it. We prefer it in black, since the two-toned look isn't really our thing. On the subject of the baby throne… this car seat is categorically huge, which can look a bit awkward.
Extremely Safe: The Diono Rainier has all the standard high-end safety features you’d expect from a convertible car seat at this price point– side impact protection, a steel frame, reinforced aluminum sides, and energy absorbing foam. It does not have an anti-rebound bar, but it does have a rear-facing tether, which provides a similar safety benefit by helping to prevent seat rotation during a collision. Above and beyond the Radian rXT, the Rainier has reinforced extra deep sidewalls lined with energy absorbing foam to protect baby's head and body in a collision.
Newborn Compatible: The Rainier is suitable for babies five pounds and up using the included infant inserts. That said, this seat totally looks like a baby throne in infant mode (and we don’t mean that as a compliment). The seat is super tall and extends way beyond the height of an infant, which comes in handy as baby grows, but is a bit of a space hog for those early days.
Rear-Facing Until 50 Pounds: This seat comfortably supports rear-facing until 50 pounds, which is around year four of a child’s life. The fact is, the longer a child can rear-face, the safer they’ll be in the event of a collision. Even once a toddler/small child’s legs are scrunched up against the back seat, it is still significantly safer to ride rear-facing than forward-facing. (Cue to 1:30 in this kind of disturbing video to learn more.)
Forward-Facing Until 90 Pounds: This is one of the highest forward-facing five-point harness weight limits out there. We like.
Converts to Booster Seat: The Radian rXT converts to a booster seat for kids 50 to 120 pounds.
Travel Friendly-ish: The Rainier folds flat for travel, which is more of a cool gimmick than a practical feature. The car seat still weighs nearly thirty pounds, so regardless of how bulky it is (or isn’t), it’ll still be a pain to schlep.

Things We Don't Love As Much

Janky Construction: The Rainier feels poorly made compared to car seats like those from Nuna, Clek, and Peg-Perego, which isn't a huge surprise consider the price point is ~20% less expensive for the Diono seat. We especially hate the way the base attaches to make the seat safe for forward vs. rear-facing and the fact that the harness must be rethreaded.
Not Super Easy Install: Attaching the base to the car seat feels a bit dicey, like you're going to pinch off your finger, but once that deed is done the install itself is pretty straightforward.
Rethread Harness: The harness must be rethreaded as your baby grows. This is kind of a pain, but thankfully, not something you have to do very often.
Limited Recline: The Radian rXT only has one recline angle.
Too Wide for Three Across: If you need to fit three carseats in your backseat, the Rainier is not for you since the extra deep sidewalls make the seat 18.5 inches wide at the top.
Heavy: At 28.4 pounds, the Rainier is not a car seat you want to be moving from car to car with any sort of frequency. Most people rarely move their convertible car seats from car to car, so weight is really not much of an issue.