Consumer Reports is rating the Bell 4Forty bicycle helmet a “Don’t Buy: Safety Risk” after the chinstrap buckle broke in CR’s routine bike helmet testing.

Wearing a helmet is the best way cyclists can protect themselves from head injuries—especially potentially fatal ones. But a helmet can provide suitable protection only if it works as designed. That’s why Consumer Reports regularly tests helmets: Our new 2018 helmet ratings will be released later this summer. (For more on how to choose a helmet and how we rate helmets, see our guide here.) 

The Bell 4Forty’s helmet retention system—the chinstraps and buckle that should keep the helmet securely on your head in the event of an accident—failed to work properly during testing of two samples of the helmet. In both tests, the buckle that fastens the straps together under the chin broke apart.

A buckle failure like this can allow the helmet to come off your head or get pushed out of position during an accident so that it no longer offers any protection, says John Galeotafiore, Consumer Reports’ associate director of product testing. “If the helmet is not in the right place,” he says, “it’s not going to work.”

The Consumer Product Safety Commission has a standard to evaluate the strength and holding power of a bike helmet’s chin strap and buckle. Consumer Reports’ helmet tests are modeled after—but not identical to—the CPSC’s standard. In our labs, we use a weight to tug at the retention system, simulating what might happen in the event of an accident, such as falling off a bike and hitting the road. (See the video above.)

More on Helmets

Consumer Reports puts every bike helmet through the same series of tests. Of the 24 helmets we evaluated this year, the Bell 4Forty was the only one that failed our retention-system strength test.

“It’s not something we see often,” Galeotafiore says.

As is our practice when we discover a safety risk during product testing, we notify the appropriate agency, in this case the CPSC, along with the manufacturer. We are not aware of any injuries related to buckle performance on the Bell 4Forty helmet and have not found mentions of problems with this particular buckle in user reviews on various websites or on the CPSC’s SaferProducts.gov website.

In response to CR’s findings, Bell Sports has performed additional testing on the helmet and is looking into the matter further.

“The buckle used in the Bell 4Forty is widely used in the industry, and has a proven track record of safety,” the company said in a statement provided to Consumer Reports. “The retention system on the Bell 4Forty was subjected to rigorous pre-launch certification testing both in-house and at an independent CPSC-approved lab, and all batches undergo further testing for safety compliance. We appreciate the information from Consumer Reports, and are thoroughly investigating the findings.”

Wearing a helmet is essential whenever you ride a bike. If you already own a Bell 4Forty helmet, our advice is to replace it as soon as possible. Use this helmet only if you do not yet have access to another helmet and need to ride your bike.

CR’s product safety experts say that using this helmet in spite of its poor performance in our retention system testing is better than riding without a helmet.

In our most recent bicycle helmet ratings, we recommend 16 helmets for adults. The two that got the highest scores are the Scott Arx Plus, $125, and Bell Muni, $65. Our updated ratings will be available later this summer.