Forcefield Pro Sub 4: Review

The choice to ride a motorcycle comes with risks.The way we go about mitigating those risks gives rise to different schools of thought on what’s appropriate safety-wise. On one hand you have ATGATT fanatics screaming the merits of Kevlar and Lorica, on the other you have squids and skull-capped cruisers who leave it all to fate… and the local ER. Regardless of your affiliation, or more likely your shade of gray on the continuum of safety awareness, the level to which we can protect ourselves today is something to be marveled at. Case in point: the Pro Sub 4 back protector by Forcefield.

Forcefield Pro Sub 4

The Pro Sub 4, as Forcefield puts it, is “designed to withstand greater impacts than any other motorcycle back protector currently available.” This seems like a lofty claim, until you see the numbers to support what Forcefield has accomplished with the Pro Sub 4. By transmitting only 3.38kN of force according to the CE EN1621-2 Level 2 test, the Pro Sub 4 is in fact the best back protector available when it comes to stopping the transmission of energy.

What does 3.38kN of transmitted energy mean, you ask? By carrying out the EN1621-2 Level 2 test, sciencey folk are able to smash things and get a relatively accurate number on how much the thing they were smashing got smooshed. In order to reach CE level 2, only 9kN of force are allowed. What you have with the Pro Sub 4 is a product that more than doubles the requirement for a CE level 2 rating. A simple way to think about this is the lower the force, the less you’ll feel the impact, and currently the Pro Sub 4 allows the least amount of force. You can find a more thorough explanation of CE standards at


The ability to reduce impact is the Pro Sub 4’s main attribute, but not its only one. After wearing it for ten minutes, it will start to conform to your back—feeling nearly non-existent. The adjustability is also a highlight. Having a rather long torso (23″ from shoulder to hip), I chose an XL—the size recommended by the Forcefield size guide. XL anything usually ends up being a bit large on my not-so-chubby frame, but the Pro Sub 4 snugs down enough to fit like a glove.


The downside of the Pro Sub 4 is its bulk and lack of “hard” protection. At about 1¼”, the thickness added is noticeable. The removable cover makes it washable, but is also a part of what adds to the heft. The lack of a hard shell might deter some, but it all comes down to what you’re comfortable with. The benefits of a hard shell lie in its ability to stop things like punctures, whereas the Pro Sub 4’s softer system is better at absorbing blunt forces. The pro Sub 4 addresses this concern with a layer of plastic (shown below), but it certainly isn’t akin to something like the Dainese Manis D1, which offers a full polypropylene shell.


The lack of hard protection isn’t all bad though, and is the reason I ultimately chose the Pro Sub 4. Short of tearing this back protector in half, it will continue to perform at it’s designed level for as many crashes as you can thrown at it— something Forcefield has aptly dubbed “Repeat Performance Technology.” Back protectors like the Tryonic Feel 3.7 offer superb protection and a hard shell, but are one and done in the event of an off-bike incident. It’s the Pro Sub 4’s ability to take a lickin’ and keep on tickin’ that appeals to my budget-minded sensibilities.

Reusability, comfort, adjustability, coverage, and (most importantly) safety are what drove me to purchase the Pro Sub 4. While I haven’t had the pleasure of testing Forcefield’s claims, I have worn the back protector in both track and street scenarios. While being a tad overboard for daily use, the Pro Sub 4 offers extremely high amounts of protection regardless the application—and ultimately protection is what you’re looking for when mitigating risk. Whether you’re an ATGATT guy or just appreciate innovation, the Pro Sub is definitely worth a look.

Photos by: Essential Moto

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