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Installing your Radian®

Installing your Radian®

Installation advice and tips to getting that perfect Radian® install from our team of expert Child Passenger Safety Technicians. 

Your car seat manual is one of the most valuable pieces of information you can find.

Watch this video to learn where the manual is located in your Radian® R Series and Radian® Q Series. On the back of your Radian® Q seat you’ll see a book icon that indicates the manual is stored inside that door. Simply flip it up and you’ll find the manual. On the Radian® R seat you’ll find the same icon on the child’s left side of the seat, that means the manual can be found underneath the cover. Simply undo the cover and pull out the envelope containing the manual. Just in case you’ve lost or misplaced your manual, you can find all of our manuals for new and older models at

We often see caregivers checking their car seats from top to bottom for a secure installation. However, our very own CPST, Scott, explains that the ONLY place to check for a secure installation is at the belt path being used. Simply give it a firm handshake and if it moves less than one-inch side to side or front to back, it’s secure.

Remember to follow each step of your car seat manual when installing your car seat to achieve the best fit for your vehicle.

The Diono Angle Adjuster is used with a rear-facing Diono Radian® car seat to give you additional space between the vehicle seat and the car seat itself. On the Angle Adjuster you’ll find arrows which tell you the direction to slide it underneath the seat. Follow the instructions to install your rear-facing Radian®, then grab it at the top, lift it up and slide under the Angle Adjuster until it stops against the back of the rear-facing base.

It is important to remember that the Angle Adjuster can only be used with rear-facing kids who can sit up unassisted and have complete head control. If neither one of those requirements is met, at whatever stage of development your child is at, then you cannot use the Angle Adjuster.

The Diono Radian® is the original 3-across all-in-one car seat. We're often asked, "will a Radian fit 3-across in my vehicle?" Our CPST, Scott, explains how to find out.

"Truth is, it’s not always an easy yes or no answer; a lot of it depends on the actual physical space in your car. Diono car seats are 17 inches wide so you need a bare minimum of 51 inches of space from one side to the other in your back seat. The other thing you have to think about it actual seat shape and seat contour, if there’s a big hump in the center, and where your seatbelts are located. Sometimes in a situation like this where the seat belts are right next to each other, a car seat might actually sit on one or both of the seat belt buckles. In this scenario, you might have to fudge the seats and move them a little bit to get them to install correctly. I always recommend installing the center seat first to see if you can get a good installation there and then move to the outboard positions to see if you get good installations. If that’s true and you can get a solid installation in all three seating positions, then 3-across will work for you."

Bracing is when a rear-facing car seat touches the vehicle seat in front of it. Diono® does allow for bracing IF the vehicle manufacturer allows it. To check, simply head to the airbag section of your vehicle manual and see if it mentions anything about not allowing anything to touch the back of the vehicle seat, or put pressure on the vehicle seat from underneath, or hanging anything heavy in the seat pocket.

If any of those things are prohibited, bracing is not allowed because it could interfere with the airbag sensors in the seat. In that case, the vehicle seat will need to be adjusted so there is a space just wide enough for a pencil’s width between the vehicle seat and the car seat.

If your vehicle manual doesn’t mention anything about airbag sensors, bracing should be okay.

Check out the Diono Angle Adjuster for a solution in vehicles that do not allow bracing. The Angle Adjuster is a foam pad that sits under your rear-facing Diono car seat and changes the recline angle just a little, freeing up space between the vehicle seat and the car seat. It’s important to note that the Angle Adjuster can ONLY be used with a rear-facing child that can sit up unassisted and has complete head control.

Radian® all-in-one car seats require the adjustable bottom to be dropped when the passenger is riding forward-facing and weighs more than 25 lbs.

Simply locate the two bars on the bottom of the seat, squeeze together and pull them out until you see the bottom has dropped and is locked in position.

If you are using your Radian® all-in-one car seat in rear-facing or booster mode, you do not need to adjust the bottom.

Remember to check that it’s locked into position each time.

Safe Stop is a load-limiting device that is included with every Radian® convertible car seat. It is required for use for passengers that are forward-facing and weighing less than 40 lbs.

The Safe Stop is located at the back of the seat and is installed between the harness straps and the harness adjuster strap.

In a crash, Safe Stop is designed to expand like a bungee cord and increase “ride down,” which is the amount of time a child is moving forward after initial impact. By increasing ride down, Safe Stop is able to decrease the forces that are exerted on the child’s body.

Had an accident or just need a back seat refresh? Here's an in-depth insight into removing and re-installing your Radian® car seat covers quickly and easily. This video applies to the following seats: Radian® 3QXT+® FirstClass™ SafePlus™, Radian® 3QXT® SafePlus™, Radian® 3QX SafePlus™, and Radian® 3RXT® SafePlus™. 

Top tip!
The rear-facing base can be used as a stand to help support the seat during the process of removing and installing the cover.

Removing the cover:

  • Step 1: Make note of which harness slots your child is using. Remove the harness straps from the adjuster strap and pull them through the front.
  • Step 2: Raise the adjustable head support to its highest position and remove the cover.
  • Step 3: Remove the fabric from the channel around the shell of the seat. 
  • Step 4: Lower the head support to its lowest position. Undo the top fabric panel by removing the buttons in each lower corner of the panel. 
  • Step 5: Remove the elastic loops holding the lower fabric panel in place. Raise the head support and fold the fabric panel down.
  • Step 6: Remove the elastic strap from the small tab on the lower side of the seat shell. A pen or similar tool will help guide the elastic around the tab. Repeat on the other side.
  • Step 7: Remove the cover from the seat shell. Begin by lifting the front of the cover and pulling the crotch buckle through the cover. Lower the head support and pull the cover off the seat shell. 
  • Step 8: If present, remove the white foam piece. Remove the memory foam. Depending on the model of your seat, the memory foam may be inserted differently in the cover. The cover is now ready to be cleaned per the instructions in your manual. 

Installing the cover:

  • Step 1: Insert the memory foam. Depending on the model of your seat, the memory foam may be inserted differently in the cover. If present, insert the white foam piece.
  • Step 2: Starting at the front of the seat, feed the crotch buckle through the cover. Insert the plastic tabs on the cover into the slots in the front of the seat shell. Place the cover loosely around the seat shell. 
  • Step 3: Fold the top fabric panel out of the way and raise the head support to its highest position. Hold the lower fabric panel in place as you lower the head support. Reattach the elastic loops around the tabs.
  • Step 4: Push the buttons in the top fabric panel through the holes in the lower fabric panel and snap them into the seat shell. Raise the head support to its highest position.
  • Step 5: Loop the elastic strap around the plastic tab on the lower side of the seat shell. A pen or similar tool will help guide the elastic around the tab. Repeat on the other side.
  • Step 6: Feed the edge of the cover into the channel around the seat shell. A credit card or similar tool will help push the fabric into the channel. 
  • Step 7: Install the head support cover. Make sure and push the fabric into the channel around the head support. There are plastic tabs on the top and bottom of the cover that help secure it to the head support. 
  • Step 8: Reattach the harness. To ensure the straps do not get twisted, buckle them before feeding them through the harness slots. 

Make sure the adjuster strap is not twisted. Attach the harness straps to the adjuster strap, starting with the child's left strap. Your seat is now ready to use!

Car seats get messy! We can't prevent that but luckily, Radian® covers are easy to remove and washable so you can keep them looking their best. Have a Radian 3RX or 3RXT? This tutorial is for you!

Scott walks through how to remove the cover of a Radian® R Series all-in-one convertible car seat.

  1. Firstly, loosen the harness as you’ll be undoing it from the back to pull the harness straps through
  2. Remove the harness pads
  3. Remove harness straps from adjuster strap and pull through front of seat
  4. Remove crotch buckle at rear-facing belt path
  5. Unclip fabric at back of seat at front and back of seat. Unclip at seat base where your child’s hip would be
  6. Remove cover from shell of car seat
  7. It is recommended to hand wash the cover for best results
  8. If top load machine has an agitator, we recommend washing on a gentle or a no-agitation cycle, this can also be used
  9. Hang to dry. Do not tumble dry.
  10. Do not machine wash the memory foam. Hand wash only.

Top tip! Your rear-facing base is a great tool to use as a stand.

Consult the instruction manual that comes with the car seat. It will state whether a seat can be used with Ford's inflatable seat belts.

Because we can no longer test convertible and booster seats with Ford’s inflatable seat belts, new seats going forward will not allow them to be used and this will be stated in the instruction manual that comes with the seat.

Diono all-in-one seats manufactured in 2017 and prior, and the Cambria and Monterey booster seats manufactured in 2017 and prior will continue to be approved for use with Ford's inflatable seat belts.

If you need further clarification, please call our Customer Service team at 855-463-4666.

For even more installation tips, check out some of our blogs jam-packed with safety advice and information to keep in mind as you buckle up for adventures with your Very important Passengers™. You can also reach out to our customer service team via the Live Chat or emailing with any installation queries.

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