Child car seats from Britax, Cosco, and Harmony
The Britax Frontier ClickTight, Cosco Finale, and Harmony Defender 360 booster seats (shown left to right)

In Consumer Reports' recent evaluations of toddler booster child car seats (often referred to as harness-to-booster seats), the performance of four models raised safety concerns when parts of each broke during testing. The four seats are the Britax Frontier ClickTight, Britax Pioneer, Cosco Finale, and Harmony Defender 360.

In 2014 Consumer Reports launched its own comparative child car-seat testing protocol to simulate real-world crash conditions after several years of research and development. CR’s goal was to differentiate car seats that provide an additional margin of safety above the basic level already provided, because child restraints must meet a federal standard to be sold in the U.S.

The organization has put several types of seats through this new test—infant, convertible, all-in-ones, and boosters—and toddler booster seats are the final category. Seats are evaluated for their crash protection on a scale of Basic, Better, and Best. All four of these seats score a “Basic” for crash protection.

Toddler booster seats are typically used for kids who have outgrown the height or weight limits of their rear-facing seat until they are big enough to use the vehicle belts alone. They are initially used with a five-point harness system to restrain the child, and after he outgrows the harness, he transitions to using the seat in booster mode with vehicle’s seat belts to restrain him.


In CR’s crash evaluations, testers found that the load-bearing components at the rear of the seats broke when tested with dummies whose weight was near the seat’s limits for its harness system.

In real-world crashes that are as bad—or worse—as the ones simulated in our tests, these structural failures would increase the risk that a child’s head could come into contact with some part of the vehicle’s interior, or that the child might even be ejected from the car seat. Consumer Reports knows of no injuries related to the structural failures revealed in our crash tests.

Here’s what you need to know, what the manufacturers told us after reviewing our findings, and what our experts recommend you do.

What Happened in CR’s Tests?

The four models had structural components that broke in CR’s tests with dummies that simulate an average 6-year-old child and either a heavier 6-year-old or 10-year-old. These standardized crash-test dummies match the height and weight of kids in those specific child restraints and are the same dummy sizes used for compliance testing of these seats. In some cases, the harness systems were damaged and, in one case, the structure supporting the top tether—an important feature that anchors the car seat to the vehicle—was too.

Britax Frontier ClickTight, Britax Pioneer Booster Seat
The Britax Frontier ClickTight (left) and the Britax Pioneer booster seat

Britax Frontier ClickTight, Britax Pioneer

  • The harness support hardware at the rear of the seat’s shell in the child’s shoulder area broke in our tests.
  • For the Britax Frontier ClickTight, the structural damage was severe enough that the harness “pulled through” the seat completely, allowing the harness to loosen in one test conducted with a 78-pound dummy, which simulates an average 10-year-old child.
  • In two tests for the Britax Pioneer with a 62-pound dummy that simulates a heavy 6-year-old and in two tests (one with each model) with a 52-pound dummy that simulates an average 6-year-old, the structure that supports the headrest and harness broke, but the harness did not pull through. 
  • The seats did not exhibit any structural issues in tests with a 35-pound dummy that simulates an average 3-year-old. 
  • The maximum weight limit for using the harness with the Britax Frontier ClickTight is 90 pounds; it is 70 pounds for the Pioneer.

According to a statement from the company, “The Britax Harness-2-Boosters tested by Consumer Reports are safe when used as intended and in accordance with the instructions and warnings contained in the user guides.” Britax also said the company would “continue to stay engaged with Consumer Reports to benefit from their perspective.”

Cosco Finale Booster Seat

Cosco Finale

  • The structure that anchors the seat’s top tether broke in our tests, enabling the top tether strap to extend. This allowed the seat and dummy to move farther forward than in tests where the top tether anchorage remains intact, and it resulted in pieces of sharp plastic in areas that may contact the child. 
  • This occurred both times we tested with a 52-pound dummy that simulates an average 6-year-old and in one test with a 62-pound dummy that simulates a heavier 6-year-old. 
  • Though the seat did show signs of stress in the top tether area, it did not break through in tests with the 35-pound dummy that simulates an average 3-year-old. 
  • The maximum weight limit for using the harness with the Cosco Finale is 65 pounds.

Dorel Juvenile, the parent company for Cosco, responded in a statement by saying: “The Dorel Cosco Finale combination child restraint has performed well with respect to all NHTSA crash performance requirements and in real-world use. There are over 350,000 Finales in use and there have been no injuries reported.” The company noted that CR’s testing varies from NHTSA’s standards. “Dorel takes the results of the Consumer Reports testing seriously and is currently evaluating the findings,” the statement said.

Harmony Defender 360 Booster Seat

Harmony Defender 360

  • The support hardware at the rear of the seat’s shell in the child’s shoulder area broke in our tests. This allowed the harness to “pull through” the seatback and loosen as the child-sized dummy moved forward. 
  • This occurred in one of two tests with a 52-pound dummy simulating an average 6-year-old and in both tests with a 62-pound dummy simulating a heavier 6-year-old. 
  • The seat did not exhibit any structural issues that allowed the harness to loosen in tests with the 35-pound dummy simulating an average 3-year-old.
  • The maximum weight limit for use of the harness with the Harmony Defender 360 is 65 pounds.

Harmony, in a statement to CR, said that its seat meets all current U.S. federal standards. The company also said that CR’s testing “did not take into account practical matters such as how the car seat fits or installs into vehicles, which affects overall safety greatly …” Harmony pointed to what it described as “several discrepancies within Consumer Reports' testing that differs from other testing, both independent and internal” that would “impact the testing results greatly.” The company did note that it “appreciates all comments from customers as well as independent bodies such as Consumer Reports as all such information is always used in the ongoing improvements of all our products.”

CR’s results reflect each seat’s performance in the crash-test portion of our evaluation, and each model’s Overall Score includes our assessments of how easy a seat is to use, as well as how easy it is to securely install. We install them in a variety of vehicle types.  

What Can You Do?

  • Don’t stop using your child car seat unless you have one to replace it. Any car seat is better than no car seat, and these seats all provide a basic margin of safety. 
  • If your child is using the seat in booster mode, continue using the seat that way because the vehicle’s seat belt is securing your child, not the seat’s own harness. 
  • Continue using the seat’s harness if your child weighs 40 pounds or less. 
  • If your child weighs 40 pounds or more (the minimum weight allowable for booster use in these seats), you can use the seat in booster mode if he can bend his knees comfortably over the front of the booster seat and can achieve a proper vehicle belt fit. That means the belt is centered on the shoulder and sits low across the hips. 
  • If your child weighs 40 pounds or more but is too small to comfortably bend her knees over the front of the booster seat or can't achieve proper vehicle belt fit in booster mode, replace your seat with a different, forward-facing harnessed car seat.

We are in the process of finalizing our ratings for toddler booster seats using our updated crash-test protocol. So if you are looking for a new seat to accommodate your child in the weight range of 40 pounds and above, you can consult our ratings for convertibles or all-in-ones.

How Can You Reach the Companies?

If you would like to contact customer service for any of these models, they can be reached at:

  • Britax: 888-427-4829 or its website
  • Cosco: 800-544-1108 or its website
  • Harmony: 877-306-1001 or its website

How Is Our Test Different From the Federal Government’s?

Consumer Reports’ test setup is designed to be more representative of current vehicle interiors. We place a surface in front of the child car seat that simulates how the child and seat might interact with the back of a front-row seat. Our test is run at a higher speed than NHTSA’s (35 mph vs. 30 mph). Because of that, it transfers more energy to the car seat and test dummy than the government test does. These differences from the federal requirements are intended to better represent current vehicles and highlight car seats that provide a greater margin of safety by subjecting them to a more challenging test.