Between the Maxi Cosi Pria 70 and Diono Radian 3RXT, the Pria 70 surely has minimal features to offer. Yet its simplicity could lessen the possibility of inappropriate usage and installation. 

The Diono Radian 3RXT, on the other hand, is loaded with extra features for safety but such intricacy may lead to a complexity that could contribute to improper use and installation.

Considering only the list of features, it is easy to choose the Radian 3RXT over Pria 70, but you need to keep reading below so you would know other factors that could be crucial in your decision-making.

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ideal use


Maxi Cosi Pria 70
Diono Radian 3RXT
Rear-Facing Weight:
9 to 40 lbs
5 to 45 lbs
Rear-Facing Height Limit:
Up to 40 inches
Up to 44 inches
Forward-Facing Weight:
22 to 70 lbs
20 to 65 lbs
Forward-Facing Height Limit:
Up to 52 inches
Up to 57 inches
High Back Booster Weight Limit:
50 to 120 lbs
High Back Booster Height Limit:

40 to 57 inches

The child’s shoulders must be at or above the 4th set of harness slots.

The Diono Radian 3RXT offers extended rear-facing and booster mode use. Although the forward-facing weight limit of Pria 70 is higher than the Radian 3RXT, the latter has a high back booster mode to accommodate a child’s growing body.

There are other things that should be considered when you are already using the car seat. One of these is the recline. As a convertible car seat, we think of using either of them beginning from infancy.

The Radian 3RXT appears to be a “better option” since it has a minimum rear-facing weight requirement of 5 pounds while Pria 70 requires at least 9 pounds. Children at such ages still have no capability to support their heads and neck. 

The Radian has a fixed angle and cannot be adjusted to a more reclined position that newborn babies require.

Even if the baby has grown and gained weight that the harness straps fit correctly, the lack of proper recline will still not be safe for the baby if their head falls forward or slumps because of inability to support their own head. 

Meanwhile, the Pria 70 can be adjusted to a more reclined position and is, therefore, a better option for children who still cannot sit unassisted.

will it fit in my car?

 Maxi Cosi Pria 70Diono Radian 3RXT
Width19.5 inches17 inches
Height25.5 inches28.5 inches
Depth/Length22.8 inches16 inches

Fit in Car. 

Being able to fit in a car as the only car seat for a child, either of these car seats will probably not cause any issue.

Yet, the Diono Radian 3RXT is a better choice for saving space in a car if you want to install 2 other car seats in the same row or if you want other passengers to enjoy ample space inside the vehicle.

Pria 70 somewhat affects the legroom of the front passenger when rear-facing. If you set the headrest at the highest position, they say that your rear-view will not be affected. One mom said that it fits perfectly in her Toyota RAV4.

Placed inside a 2017 Honda CRV, another parent claimed that it still left enough room for the front passenger.

The car seat is on the bulky side and one parent even noted that the car seat occupied not just one, but one and half seating space in their Toyota Avalon.

The Pria 70 was also said to have been installed with minimal challenges in an Acura MDX and a Toyota Tundra.

The reviews for Radian 3RXT will only confirm how it is an absolute 3-across child restraint since it is slim.

However, just as mentioned above in the section for ideal use, the 3RXT car seat offers no recline adjustment so you have to install this at a somewhat tilted position that can affect the legroom for front-seat passengers.

Diono sells the “angle adjuster accessory” that can be placed under the car seat installed rear-facing so it will be more upright. This add-on gives more legroom for the front passengers.

Take note that this setup is only advisable for children who can sit unassisted and already have good head and neck control.

Reviewers claim that this car seat is a perfect 3-across child restraint on a Toyota Yaris, Toyota 4Runner, Nissan Xterra, and 2017 Honda CRV.

A mother noted that she could fit the 3RXT along with 2 Cosco booster seats in the back row of their Ford Escape. It was also installed pretty well in a 2017 BMW 3 series, 2016 BMW 5 series, 2013 BMW X1, 2013 Ford Focus, Ford Flex, and 2017 Ford F150 double cab.


Maxi Cosi Pria 70
Diono Radian 3RXT
Do I need to use a pool noodle/rolled towel?
Allowed, according to the manual, (page 51)
Easy To Install Rear-Facing by LATCH?
Easy To Install Rear-Facing By Seatbelt?
Easy To Install Forward-Facing?
Easy To Uninstall?
Recline Position
3-position recline
Lower Anchor Weight Limit:
40 lbs

35 pounds rear-facing

40 lbs forward-facing


Both car seats feature a push-on or push-button lower anchor connector, although Diono has a specific name for it: SuperLATCH connectors.


Pool Noodle/Rolled Towel. Using these aftermarket products to install the car seat in an appropriate recline angle is allowed with Pria 70, but not with Radian 3RXT.

Recline. The Pria 70 can be reclined to a position that will suit your child’s needs. Although it only has three available recline positions, it is still better than the fixed recline of the Radian 3RXT. 

A rear-facing recline foot has to be attached to the base of Radian 3RXT.

On sloped seats, this fixed internal recline angle will make the car seat more upright when installed. If the seat bight is raised or if the vehicle seat is flat, the Radian 3RXT will be quite reclined that it will reduce the front passenger space.

To make the car seat more upright, you may separately purchase the angle adjuster from Diono.

Installation. If you look at the installation instructions of the Radian 3RXT, you would most likely feel overwhelmed and feel somewhat confused since it involves a few uncommon steps.

However, if you take time watching videos and mulling over the procedures printed on the manual, you might soon get the hang of it and install the Radian 3RXT securely, just as many parents did. 

With the help of other available resources, you could learn what other considerations are involved when installing and using either of the car seats.

With Pria 70, installation is straightforward, but Radian 3RXT has some special reminders you must take into account.

For instance, in its forward-facing installation, there is an adjustable bottom part that you first need to lower and put into place for children that are 20 to 25 pounds.

Since you might not have the time to weigh your child now and then to make sure you are within this weight requirement for the adjustable bottom, lower this adjustable bottom prior to forward-facing installation.

It is rather helpful to check out other available sources of information like user reviews to learn more about Radian 3RXT.

In one review, you could read that the car seat allows LATCH borrowing or making use of LATCH from either side when installed in the middle of the car as long as it is within 11 to 14 inches distance.

Yet, this detail is not indicated in the manual, at least as of writing this review.

Vehicle Belt Lock-off. The Radian has lock-off features in both rear-facing and forward-facing. Pria 70 will require you to use a separate locking clip or the locking feature of the vehicle seatbelt.

Belt Paths. The Radian 3RXT has color-coded belt paths that are also reflected in its manual. Blue is for rear-facing while red is for forward-facing.

For LATCH installation, Pria 70 is more convenient since the lower anchor weight limit is the same for both rear-facing and forward-facing.

Diono Radian 3RXT, 4-in-1 Convertible Extended Rear and Forward Facing Convertible Car Seat, Steel Core, 10 Years 1 Car Seat, Ultimate Safety and Protection, Slim Design - Fits 3 Across, Blue Sky
Price: $340.31
(As of: 2022/08/02 10:26 am - Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on at the time of purchase will apply to the purchase of this product.
3 new from $323.990 used
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Maxi Cosi Pria 70
Diono Radian 3RXT
Country Of Origin:
Steel Frame:
Five-Point Harness?
Side Impact Tested:
Approved For Airplane Use:
Easy To Buckle And Unbuckle?


Both are made in the US, have side impact protection, five-point harness, and aircraft use approval.


Safety Features

Despite not having a steel frame, Pria 70 has the unique Air Protect technology for its headrest side impact protection. Other car seats use foam and padding to provide side impact protection for a child.

The Air Protect from Dorel Juvenile involves pockets in the headrest that are filled with air.

In the event of a crash and the child’s head hits the headrest, the air in the pockets will be released and thus dissipate the crash forces that might injure the child passenger.

This Air Protect has received high ratings and absolute approval, especially after it has worked efficiently in many accidents.

The Radian 3RXT appears to be a feature-packed car seat. However, you might miss and skip on these amazing features if you do not read and understand more about them.

There are also instances when the safety features are inconvenient to use so some parents just skip them altogether and only use the basic features of the Radian 3RXT.

A good example of this is the Safe Stop Load Limiter. It is a small strap that is to be attached to the backside of the car seat. When it is attached, it can increase the time with which the child could feel the forces of a crash.

If you do not read the manual or read other helpful articles, you might disregard this load limiter that appears like an extra strap.

If you plan on using the car seat for different children of different weights and ages, weighing each child just to make sure the attached load limiter will work would be a problem because the safe Stop attachment is only for forward-facing children less than 40 pounds.

Another great, but otherwise easy to skip safety feature of Radian 3RXT is its rear-facing tether capability.

We normally use tethering when forward-facing and very few car seats allow this safety feature in the rear-facing. Your car also needs to have an appropriate feature for rear-facing tethering.

Top tethering helps reduce the rebound motion during an impact.

Safety Efficiency In Times Of Accidents

Based on the experience of a mom who has gone through an accident that resulted in her car being a total wreck, you could read that the design and construction of Pria 70 are amazing and efficient.

The mother suffered from whiplash and bruises, but the 9 months old baby had no injury (not even a scratch) at all.

The safety features of the Radian 3RXT, including its steel frame, most likely work effectively because there are many dire situations where they were proven to be such.

A mom said that their car was rear-ended by another car driven by a drunk driver. Although the 50 mph car had hit the side where their son was seated in his car seat, the baby got the least damage from them all.

A father commented that the police had stated that children rarely walk away from a rollover accident where the car even went over the retaining wall.  Yet, all of his 3 children survived with no scratch at all because of the Radian 3RXT.    

the seat

Maxi Cosi Pria 70
Diono Radian 3RXT
Is The Material Breathable?
Seat Weight:
23 lbs
28.1 lbs
Machine Washable Cover?
No-Rethread Harness?
Comes With An Infant Body Support?
Yes, body pads
Easy To Remove Cover?
6 to 8 Years
10 Years
Comes With A Cup Holder?
Shoulder Harness Has Pads?
Crotch Pads?
# Of Headrest Positions:


Both have breathable fabrics, and easy-to-remove, machine washable covers. Both also have ample room for a child passenger’s growing body, infant body support, cup holder, shoulder pads, and crotch pads. 


Harness. Pria 70 has a more convenient to use harness system. Its no-rethread harness allows you to also adjust the headrest at the same time you adjust the shoulder straps.

With Radian 3RXT, you need to make separate adjustments for the harness and for the headrest that also have different settings. There are 12 headrest positions for Radian 3RXT, but its harness system only has 5.

Extra Accessory. You might think the more accessories that come with a product, the better. However, this would only be so if you know exactly for what purposes these accessories are.

If you unbox your Diono Radian 3RXT and see the large black cushion inside the box, you should know that you must only use this in the forward-facing with no tether when installing the seat using a lap belt, not a lap-shoulder belt.

In forward-facing, top tethering is always the best instead of using this large cushion.


There is an approximately USD 140 price difference between the Maxi Cosi Pria 70 and the Diono Radian 3RXT. The Diono Radian is more expensive.

It is because of

  • its extended rear-facing capacity.
  • a higher forward-facing height limit.
  • a belt-positioning booster mode.
  • the slim feature that makes it ideal for a 3-across setup.
  • its steel frame.
  • an easier to buckle and unbuckle 5-point harness.
  • its extra added safety features like rear-tethering and safety stop.
  • a longer expiration date.
  • crotch pads.
  • more headrest positions.

However, these specified features of the Diono product would not be effective if you are unable to correctly install it or if you fail to correctly take into account its added features.

While Pria 70 appears to be just one level above the basic car seat, it can offer a much simpler installation and usage, which have been proven effective in real-life accident scenarios. Its noteworthy features include

  • a higher forward-facing weight limit.
  • easier to install rear-facing via LATCH.
  • 3-position recline.
  • “Air Protect” technology in its headrest.
  • lighter weight.
  • no-rethread harness.
The Maxi Cosi Pria 70 and
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