The 3-Across Puzzle: Clek Foonf vs. Diono Radian (2026 Guide)

For growing families, the third pregnancy often brings a panic moment: "Do we need to buy a bigger car?" Not necessarily. Before you trade in your sedan for a minivan, consider the art of the "3-Across" installation.

According to Transport Canada, keeping children in a 5-point harness for as long as possible is the safest way to travel. But fitting three harnesses side-by-side requires specialized engineering. In the world of narrow, safety-obsessed car seats, two Canadian-founded heavyweights stand out: Clek and Diono.

At baby enRoute, we have installed thousands of seats. Here is how these two narrow legends compare for the ultimate back seat puzzle.

Contender 1: Clek Foonf (The Tank)

The Vibe: Modern Industrial Safety

Clek seats are built like tanks. Manufactured in Canada, the Foonf (and its lighter sibling, the Fllo) features a rigid magnesium sub-structure. It sits high up on a base, giving kids a great view out the window, which helps with motion sickness.

How It Fits

At just under 17 inches wide, the Foonf is designed specifically for 3-across situations. Its rigid LATCH system makes installation incredibly secure and straightforward.

Key Technology: REACT™

The Foonf features the REACT (Rigid-LATCH Energy Absorbing Crumple Technology) system. Much like the crumple zone of a car, this aluminum honeycomb structure collapses during a crash to absorb energy, reducing the force transmitted to your child by up to 40%.

Contender 2: Diono Radian (The Original Slim Fit)

The Vibe: Low-Profile Versatility

Diono (formerly Sunshine Kids) invented the narrow car seat category. The Radian series is famous for its full steel alloy frame. Unlike Clek, Diono seats sit low on the vehicle seat, which makes it easier for older toddlers to climb in and out by themselves.

How It Fits

Also measuring about 17 inches wide, Diono is the go-to for tight spaces. Its low profile often makes it easier to install in cars with sloped rooflines.

Key Feature: Extended Rear-Facing

Diono seats are renowned for their high rear-facing weight limits, allowing children to stay rear-facing (the safest position) for longer. The unique folding design also makes it one of the only car seats you can fold flat and carry on your back for air travel.

The Verdict: Which Puzzle Piece Fits You?

Choose Clek Foonf if:

• Safety Tech is #1: You want the advanced crumple zone technology and anti-rebound bar standard.
• Motion Sickness: Your child needs a higher view to see outside.
• Fabrics: You prefer Crypton® fabrics that are stain, moisture, and odor-resistant (and free of brominated flame retardants).

Choose Diono Radian if:

• Travel Frequent: You need a seat that folds flat for airplanes.
• Independent Toddlers: The low profile allows kids to self-board.
• Budget: You need to buy three seats at once and want a more cost-effective option without sacrificing the steel frame safety.

Don't Guess—Test!
Every car's back seat is shaped differently. The only way to be 100% sure is to try it. Visit baby enRoute in Richmond or Ottawa, and our certified technicians will help you test-fit these seats in your actual vehicle to find the perfect 3-across configuration.