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 R100, R120, 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
|
Features
|
| R100
*Discontinued |
5-40 lbs.
|
20-65 lbs.
|
50-100 lbs.
|
|
| R120
*Discontinued |
5-45 lbs.
|
20-65 lbs.
|
50-120 lbs.
|
|
| RXT
|
5-45 lbs.
|
20-65 lbs.
|
50-120 lbs.
|
|
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.
Installation
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.
vs. 
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.
Advantages
- 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
Disadvantages
(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
Conclusion
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!
Do you think any of the Diono’s make a good forward facing harness to booster? The Olympia perhaps? Second son quickly outgrowing Boulevard (91st percentile for height). Not impressed w/Pioneer that my older son uses (waiting to receive replacement from Britax). So, trying to avoid Frontier. If not Diono, any suggestions for ff harness to booster for tall kids?
For rear-facing, the new Rainier won’t be different for you. The difference comes in forward-facing where it’s at least an inch wider at the shoulders. That may make a difference when you’re dealing with a 3-across. My review of the Rainier will be out *very shortly*.
Thank you so much for your reply. Funny enough, we bought a Harmony Defender for grandma’s car last year and my husband just mentioned it earlier today. We looked at the width online and when we saw how narrow it is, we then couldn’t figure out why we haven’t seen it mentioned much on blogs and forums that specifically talk about 3-across! I think that is what we will do for the 5 year old (especially since the price is so much nicer!). Do you see any benefit in getting one of the new Diono models that just came out vs. the RXT? I’ve had trouble finding the width of those new ones but if they are narrow still, is there much difference (besides the price)? Thank you again!
I am in need of two new seats and have been looking at the Radian RXT. My youngest son is 21 months, RF, 34 lbs., and currently in a Britax Marathon that just expired this month. Keeping him RF as long as possible is a priority. My older son is 5 years old, 46 lbs. He is currently harnessed in a Britax Pioneer but we are moving that seat to my husband’s car. I want him to remain in a harness as long as possible. I drive a 2011 Honda Accord and am hoping to add baby #3 to our family soon (will need to buy a new infant seat since my other is expired) so seats for my two current boys that are narrow enough to fit 3 across in the future are important (hence the reason I am looking at the Radian). I’m thinking the Radian is a good choice for my 21 month old but am undecided for my 5 year old. Thoughts? If not the Radian, what other seat is narrow like the Radian yet also will allow me to still keep him harnessed (and be a good HBB in the future when he does outgrow the harness)? Thanks so much!!
@Aliceson, the Radian is definitely a good choice for your 21 mo old given that you want a 3-across in your Accord, but I wouldn’t get one for your 5 yr old. I guess you could use it as a harnessed seat for him until his shoulders get to the top slots, but I wouldn’t use it as a booster. Then you could pass it down to the baby and put him in a dedicated belt-positioning booster. Another narrow option for your 5 yr old is the Harmony Defender.
@Jean, that’s exactly what I remember it doing. Now that I’ve had a bit more time to practice with it, I’ve learned some tricks. The best thing to do to solve the submarining issue is to drop the forward-facing recline down. It’s deceiving because you think it’s not going to do anything, but it does solve many ff install issues. Remind me of the center seat belt stalk–is that the metal stalk? There’s really nothing you can do about that. You can try dropping that recline down and see if that helps, but the seat belt will still get wonky in the latchplate. It’s not a problem for the seat belt to do so, but it will make it difficult to pull tight and may cause the seat belt to twist in the latchplate if you’re not careful.
I’m sorry if you answered this in earlier comments, but what install issues did you have in your Sienna? I feel like my submarines in the third row outboard and I can’t get it tight in third muddle because if the seatbelt stalk.
@Kitsy, with the Radian, you’re stuck with the recline that you get because of the recline foot that comes with the seat. If she has excellent head control, you can buy the angle adjuster and use that with the seat, but it puts the seat at a much more upright angle.
All Radian seats require rethreading of the harness. It shouldn’t happen often with a rear-facer and should be pretty easy to do because you don’t have to uninstall the seat. But I hear you on the PITB it is to do it :).
Hi!
I want the radian for my now 5 month old daughter who is 23+lbs and over 25 inches already. My 4 yr old is already 43 inches tall. I have rather chunky and very tall kids.
My questions are:
can I put my 5month old in the rf position with no recline? She is most comfortable upright and has exceeded her infant seat. I want to extend rf as long as possible.
Also, is there a no-rethread on the radian? I hate rethreading it when adjusting straps.
Thanks,
Kitsy
Hello, I’m in the market for a new car seat and my main concern is finding a safe, easy to install seat that takes up a minimal amount of space. Throughout the research I’ve done, the RXT constantly comes up, but I haven’t seen much else out there. I know there must be some other 17″ width options out there, so I thought I’d check with you. I plan on having the seat forward facing for a 4 year old (37″, 30 lbs). I did see the Clek Foonf, but the price tag on that one is hefty and I wonder if the lower weight restriction would be a problem in the future, though she is on the tiny side. Is there any difference between the 2014/2013 Foonfs? They seem to be lower in price, so might be a better option if they have all the same bells and whistles. In a direct comparison between the RXT and the 2013 Foonf, which would you side with? I’m also concerned with strap tightening. I find that I have to tighten and loosen the straps on her Argos 70 a lot and have heard that the RXT can be a challenge. On top of that, she’s recently figured out how to loosen the straps of the Argos herself. That scares me because she really hates when the straps are tightened correctly, so always loosens them an unsafe amount. Ok, I think that’s it! Thanks in advance.
@David, I’m sorry I missed your comment. My answer is probably just because it’s less likely that the shoulder belt will get caught in the belt guide. However, by the time kids are ready for booster use, it’s really much better to use a dedicated booster seat. They work better as boosters in belt positioning and in not grabbing the seat belt.
@Paras, thanks for the compliment :). Bent legs aren’t a safety issue at all. In a crash, everything moves toward the point of impact. The most common type of impact is the frontal impact, so what happens is that the legs will fly up toward the front of the car. As they come down, they’re bent, which means they’re less likely to be injured. OTOH, legs are most commonly injured when kids are turned forward.
Thank you for such an amazing review that covers almost everything. My daughter is 6 months old and I am planning ahead. She is super tall, like in the 96 percentile tall and so I was thinking that Diono would be the best option since I would like to keep her rear facing for as long as possible (saftey reasons), but I was just wondering won’t her legs have to be cramped up or bent to fit rear facing for too long? Is Diono designed it a way so a tall child’s legs have enough room when they are around 3 years old? I am under the impression that bent legs is a safety issue… Please let me know your thoughts. Thank you for your time.
I’m looking at the Radian line in order to fit three seats across the back of the car. They are fairly expensive and I would like to use them as booster seats in the future. Do the R100 and R120 work better as booster than the RXT?
@Mike, yes, that’s perfectly normal movement for every rear-facing carseat. You can use the tether and secure it rear-facing using the small strap attached to the end of the tether. There’s more information on how to do that here: https://carseatblog.com/12749/how-to-use-a-rear-facing-tether/ .
I am using the radian rxt in rear facing mode using a shoulder/lap belt. Although there is little movement at the front of the car seat where it is anchored by the seat belt, there is a lot of movement at the back and top of the car seat. Is this normal?
@Sarah–Thanks! YOU ARE AWESOME!!!
@Sharee, sorry it’s taken me a few days to get back to you. I’ve been away with limited computer access. Is your truck the one with the smaller back doors as opposed to the back doors that are the same size as the front doors? If so, I’m afraid the Radians might be too tall to fit, even with the angle adjuster. Since you have the KeyFits in there, you might be able to get the Chicco NextFit to work. Do you have a Babies R Us nearby where you can try one out in your truck?
A note about the Radian RXT on an aircraft (RF). I’ve done it. More than once. I found the following: Its a VERY tight fit. I felt like it wasn’t “flat” like I had hoped it would be (and the angle adjuster I placed under it still didn’t get it JUST right – in fact that angle adjuster was still a tiny bit “loose” under it. I used a seatbelt extender (just to make tightening it easier – the aircraft belt DID fit, but I had a hard time getting my hands in there to get it tightened. extender made that much easier!). There was minimal to no side-to-side movement (far less than 1″) the “issue” was it was almost being “braced” just a tiny bit by the seat in front (even with the angle adjuster in place). Disclaimer…. I was traveling solo with a feisty 17 month old so I suppose its possible someone else might be able to get a better fit without pausing to retrieve a toddler who’s now visiting the smiling passengers 3 rows over!
I made a “parental decision” that I was more comfortable with her RF and SLIGHTLY “off angle” to what is ideal because I felt it would protect her better with forward impact collisions (such as problems taking off/landing) I personally felt that in the event of a major catastrophic collision – the seat not being installed “perfectly” per say was not going to make the difference….
Just wanted to pass along – there wasn’t QUITE enough space to be RF “perfectly” but it was extremely close and I felt comfortable with it. I want to share my experience so others to have the most complete information to make the choice they feel is best for them. I hope it helps someone!
(And I totally agree with a previous poster mentioning – the person in the seat in front of her was unable to recline. I had boarded first and already had her seat installed when everyone else boarded so I politely mentioned she wouldn’t be able to recline and she was very appreciative of my letting her know but was fine with that)
Do you know if this seat would work in a 2001 extended cab Toyota Tundra? I am guessing if the seat did we would need an angle adjuster. We presently have chicco keyfit 30’s for our twins
@Vicki, your ds may have already outgrown the Mico. Does he have at least an inch above his head in the carseat? If not, you’ll need to get him a convertible pronto! Since you are asking your question in the RXT comments, do you like the RXT? It fits well in smaller back seats with the angle adjuster. BUT, the angle adjuster isn’t currently available, at least online. You may be able to find it in a local store that sells Diono seats. If you want to consider a different seat, I’d look at a Chicco NextFit or a Graco Size4Me/Head Wise. Also see: https://carseatblog.com/22818/the-ultimate-rear-facing-convertible-space-comparison-review-size-matters/ .
Hi Heather,
My son will be turning 1 in a couple of weeks and I`ve started looking for a convertible carseat. My son is very thin (in the 5 percentile) but very tall (in the 80 percentile) for his weight. Also we drive a 2013 Ford Escape which has a very small back seat.
Right now we are using a Maxi-Cosi Mico and its already a tight fit in the passenger side. What do you recommend for this vehicle?
Hi Molly. Since the new Diono convertibles are based on the Radian models, they should be somewhat similar. But, I’ll withhold any real comment until I can get my hands on one and really tear it apart ;). Soon!
do you have any opinion about the 3 new diono car seats coming out ? how soon will you review any or all of them ? thanks!!
I bought one of these and a Recaro performance sport to check out. None of the stores within 300 miles of where I live carried either! I have an almost-5 nephew who outgrew our evenflo something-or-others and we needed something else. He has a Graco Nautilus in his mom’s car and another in grandma’s (my mom) van.
Based on experience last summer when my friend with 2 kiddos came to visit I was wanting a narrower seat in case we need to fit 3-across the backseat of mom’s minivan or my Subaru Outback (the outback has an unexpectedly miniscule backseat, with contoured cushions that can make installations at the outer edges a total pain, no center lower latch, etc…) I thought I would be in love with the Recaro and it would be worth the couple of extra inches of width (up high, where it would fit out over the wheel wells of the Honda Odyssey). I was hoping to use a USA-made seat. However once they arrived there was no comparison. The Diono fit into every spot in the Outback with ease, either latched or belted, faster and easier than any carseat i’ve used (i’ve worked as a nanny and have friends with kiddos so i’ve done a few both here and in other countries). The recaro was just huge. I couldn’t get it satisfactorily tight with the latch OR seatbelt without a lot of work (and i’m 190lbs and work out…I tend to stand in a carseat, put my back against the roof of the car, and press down hard while tightening things. Car seats dont move even an inch when i’m done. the Recaro stumped me). The Diono fit in my Outback and also in Dad’s Dodge Charger, both latched and belted, in seconds. I did have a bit of trouble UN hooking the top tether from the Charger, but a pair of pliers allowed me to get at it. now that the paint is chipped off i don’t think that will be a problem in the future. Haven’t put it in the van yet as I didn’t want dog fur on a seat i would return. Based on measurements it should work great.
It’s rock solid in any of the 3 positions in my Outback, and I belted the baby’s Graco Snugride base beside it (using the seatbelt as the latch pulls it too far in towards the center). There’s actually enough space for another PERSON to sit back there if need be!! Stunning. Fantastic. And despite the fact that we could only get it in brown instead of the blue or red the nephew had requested, he picked it over the Recaro. why? Because it has the little sheet of ’emergency information’ that tucks into the pouch in front of the seat. He thought that was such a great idea it trumped the awesome blue color and ‘racecar-builders-carseat’ design of the Recaro. (sorry this is REALLY long!)
@Melissa, it will install on a regular airplane seat rf, especially if you use the angle adjuster. Of course, the person in front won’t be able to recline, so if you are traveling with another adult, it might be nice to put that person there or buy the traveler sitting in front of your child a snack if you see a stink-eye from them. If you do travel a lot, there is something to be said for having a seat like the Scenera that weighs 9 lbs. vs. the Radian that weighs 26 lbs., lol.
Glad to help, Mari!