After the helmet, knee guards are probably the most commonplace piece of protective equipment used in mountain biking. There are almost as many variations of knee guards as there are brands selling them, but one of the more popular categories is the pull-on sleeve type. Once upon a time, this category was pretty much created by the arrival of D3O; that famously orange, viscoelastic material that is soft and malleable until you hit it with something hard, whereupon it stiffens up to disperse the impact energy instead of transmitting it to your body parts. D3O enabled the design of guards that were more comfortable to wear while pedaling without sacrificing too much in terms of protection. Fast-forward to today, and several new D3O competitors have emerged, so we thought it would be interesting to test a few of them out to see how they stack up. Disclaimer: we didn’t take heavy crashes in all of these, so this test is as much about fit and general function as it is about protection. Also, we’re not out to proclaim an outright winner, just reviewing three recent offerings to help you figure out how they are different and which one might be right for you.
Our three protagonists - Fox, DHaRCO, and ION – all share the same fundamental design: a soft and flexible sleeve that holds a main protective insert made out of some kind of viscoelastic material. Each company went their own route with regards to the main insert material, and there are certain design differences between the three guards on the whole as well. The Fox Enduro Pro uses a traditional nylon/polyester sleeve, augmented with an external sleeve that holds the insert in place, which is said to make the main sleeve less restrictive when pedaling. The CE Level 1 insert itself is made by Koroyd, the company that came up with that funky helmet impact layer that looks like it was constructed by gluing drinking straws together. Contestant #2, DHaRCO, is completely new to the protection game in general. The Gravity Knee Pad sports a main CE Level 2 insert made by RHEON, and a set of small auxiliary elements on either side of the knee. To round out this tantalizing trio, the Arcon LT from ION; it features a large CE Level 2 RE ZRO insert that extends to either side of the knee, as well as an extra protective element above the knee area. It is the burliest guard of the three tested here, and also the tallest - albeit not by much.
Our two testers are both around 6’0’ (1m84), and weigh between 187-200lbs or so (85-90kgs). Their relevant measurements follow:
Johan
Thigh (15cm above knee): 50cm
Thigh (18cm above knee): 53cm
Knee joint itself: 41cm
Calf (15cm below knee): 38cm
Nils
Thigh (15cm above knee): 50cm
Thigh (18cm above knee): 52cm
Knee joint itself: 40cm
Calf (15cm below knee): 37cm
We’ll now review each of the three guards individually, and come back with some conclusions at the end (there are also comparisons between the three guards throughout each individual review).
Fox Enduro Pro
- Koroyd inserts for impact protection and flexibility
- Abrasion-resistant Cordura® fabric on the Koroyd insert pocket
- Lightweight, minimal sleeve style construction for increased comfort and flexibility
- Large elastic gripper panels with silicone print designed to keep the guards in place while riding or during impact
- Antimicrobial treatment reduces odor-causing microbes
- Materials used: 63% nylon, 20% TPE, 9% polyester, 5% spandex, 3% other
- EN1621-1 Level 1 CE Certification
- MSRP: $129.95 USD
The Fox Enduro Pro is the slimmest and most minimalistic of the three guards tested here. It only features the one single protective insert, and that insert is also the smallest of the three. The insert is made by Koroyd, with a very open design intended to promote breathability and flexibility. The unique pattern provides for a lot of flexibility in any direction, while passing the EN 1621-1 Level 1 certification for impact energy mitigation. The other two guards in this test pass Level 2. We tested the size L, which was a good fit for both our testers. Note that the size guide on the Fox website lists some pretty strange numbers in the Thigh column, we are not sure where they measure but it has to be very close to the knee joint as those numbers make no sense at all otherwise.
The sleeve is constructed from a nylon/polyester blend that is very light to the touch and very flexible. To hold the Koroyd insert in place there is a secondary sleeve or pocket, which is reinforced by Cordura for extra abrasion resistance. There is a very wide elastic band at the top hem, with silicone grippers inside to really help the guard stay in place. The silicone used by Fox is the stickiest of the three in this test, which also makes it the most prone to grabbing your leg hairs every now and then.
On the trail, the Enduro Pro is very comfortable and does a great job of staying put while you exert yourself. The elastic band up top is very wide and quite strong, so it will make itself felt if you have heftier thighs. It is not uncomfortable, but both our testers commented on how tight it is. On the flip side, this really helps it stay in place too. The separate insert pocket does provide for a little extra mobility and freedom of movement around the knee joint, and the very soft and flexible nature of the Koroyd insert is great for comfort as well. The Enduro Pro feels OK even in very warm weather, it's not the most well-ventilated guard we've ever used but it's absolutely tolerable.
In terms of impact management, our non-scientific testing (consisting of a few minor get-offs here and there) shows that the Koroyd insert does its job, taking the sting out of direct impacts and protecting you from scuffs and cuts. As with the other two inserts featured in this test, you can argue that the very open mesh design might allow a sharp object to penetrate this layer of protection more easily, but if that is your main concern, you’re probably better off choosing a more robust type of knee guard to begin with. The use of Cordura on the front of the insert pocket adds some peace of mind here, and will also help greatly with longevity. We’ve had several pairs of these guards running all summer, and they've been able to ward off some minor slide-outs without any issues.
All in all, the Fox Enduro Pro is the lightest-duty knee guard of the three in this test, and that’s what it feels like on the trail. It is very comfortable to pedal around in but should do a good job protecting you during unplanned landings on your knees. It doesn’t have extra padding on the side of the knee, and the protective insert itself is the smallest of the three tested here, so take that into account if that’s important for you. Also mind the sizing as the large elastic strap at the top hem runs a bit tight.
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Free shipping on orders over $69 (continental U.S. only).
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Free shipping on orders over $50 (contiguous U.S. only).
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Free shipping on orders over $50 (contiguous U.S. only).
International shipping available. Some exclusions apply. $129.95
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DHaRCO Gravity Knee Pad
- Level 2 CE-certified RHEON™ insert (EN 1621-1:2012).
- Removable inserts
- Soft, flexible and breathable padding
- Pedal-friendly sleeve design
- Extra side padding for added coverage
- Ergonomic pre-curved fit
- Nylon fabric for breathability and anti-odor properties
- Silicone grippers and elastic cuffs
- MSRP: $132.00 USD
As mentioned in the intro, Australian apparel specialist DHaRCO is completely new to the protection game, having launched their first-ever range just a few months ago. They’ve come out swinging with a set of protectors developed together with the Commencal Muc-Off downhill racing team, most notably in the persons of Amaury Pierron, Myriam Nicole, and Loris Vergier. They’ve partnered with RHEON for the inserts, which they’ve used for their body armor range as well as the knee and elbow protectors. We’re focusing on the Gravity Knee Pad for this review, but we’ve also tested the lighter Trail version which shares the same underlying design while foregoing the auxiliary inserts on the side of the knee and using a lighter weight (CE Level 1) insert. If you want to step things UP another notch, there's also the Dh guard which is built around a neoprene sleeve and features a Velcro thigh strap for even better retention.
The sleeve of the Gravity guard is made from the usual nylon/polyester mix, and is said to have anti-odor properties. It subjectively feels a tiny little bit heavier-duty than the Fox Enduro Pro reviewed in the previous section. The front panel is made from a sturdier fabric than the rest of the sleeve, although no mention is made of it being Cordura or similar like on the other two guards in this test. Still, it seems plenty robust to the touch, and it also features laser-cut ventilation holes in two areas. The RHEON insert is slightly larger than the Koroyd insert of the Fox guard, and smaller than the RE-ZRO insert of the ION guard (reviewed in the next section). The Gravity Knee also gets four auxiliary inserts placed on either side of the knee joint, for extra protection from lateral impact. There is a wide elastic band equipped with silicone grippers inside the top hem. The silicone chosen by DHaRCO is very comfortable, providing good grip without unnecessarily tugging on your leg hairs. We tested the size L, which was a good fit for both our testers.
On the trail, the Gravity guard quickly won us over with very high levels of comfort. The pre-cut shape works great on the bike, and the fabrics are all soft to the touch on the inside. There are no notable hotspots or pressure points anywhere, and the guard does a great job of staying in place regardless of what you get up to in action. The extra side inserts provide a little extra insurance against lateral impacts and scuffing, while also contributing to the overall stability of the fit. Subjectively, this DHaRCO guard feels a step above the Fox in terms of robustness (not as much as a full-blown DH guard, but still).
Despite the extra inserts, the Gravity guard is easy to wear all day, and we noted no discomfort whatsoever when it came time to pedal with it. Yes, you can go even lighter with the Trail version, but we hardly see any reason to do so. The Gravity guard is plenty flexible and breathes really well thanks to the extra ventilation holes on the front panel. Whether or not these holes make it more vulnerable to tears remains to be seen – we’ve not noticed any kind of fraying or other issues in this area so far.
To conclude, we’ve been very impressed with DHaRCO’s arrival in the protection space. The Gravity Knee Pad (and the Trail version that we’ve also had some riding time with) is very well made, and offers Level 2 CE protection in a lightweight and comfortable package that is easy to wear all day. It works equally well when pedaling or descending, and should do a good job warding off anything short of the most violent impacts.
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Free shipping on orders over $50 (continental U.S. only).
International shipping available. Some exclusions apply. |
Free shipping on orders over $50 (continental U.S. only).
International shipping available. Some exclusions apply. $129.00
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ION Arcon LT
- RE ZRO® insert material, enhanced by TOTO-TOA® for biodegradability
- CE-certified: level 2
- MAIN FABRIC: 80% Neoprene 10% Polyamide 10% Polyester
- Cordura reinforced front panel
- Extended top hem silicone gripper
- Calf strap
- Laser cut venting holes
- MSRP: $129.99 USD
At the heart of the ION Arcon LT we find a protective insert developed by RE ZRO. At first glance, it’s a visco-elastic pad like so many others, but with a twist – this one is biodegradable, said to dissolve in a landfill over a matter of a few years. ION has also made it about 15% bigger than many other CE certified pads, including the two others in this test, which translates to extra medial and lateral protection of the tibia head. It wraps around the knee on either side, reducing the need for any auxiliary pads to be sewn into the sleeve in this area.
The sleeve itself is made of a mix of recycled nylon and 4-way stretch Cordura. The main insert extends quite far down the shin, and there’s an auxiliary element on top of the knee for a little extra protection in this area. Silicone grippers have been added to both hems, and there’s an extra elastic strap behind the calf for even better retention. The top hem extends quite far up the leg which also helps the guard hold on when things get agitated. As with the DHaRCO guard reviewed in the previous section, the silicone chosen by ION is of the more comfortable kind – grippy but not grabby. The overall impression of the Arcon LT compared to the others is slightly more robust. At mild to warm temperatures, the RE ZRO insert is also the stiffest in this test.
The Arcon LT runs true to size, if a little on the small side – in our experience, this is par for the course with ION guards, something to take into account if you are between sizes (we tested the size L, which was a good fit for both our testers). The Arcon provides a tight and secure fit, without any notable hotspots or other discomfort. The only thing we’d point out here is that you can feel the lower part of the main insert against your shin, this is due to the insert extending further down on the leg and also due to the RE ZRO material itself being a bit stiffer than the others tested here. This means you get a little extra protection but you’ll feel the insert moving against your shin as a trade-off (it’s not uncomfortable and has not caused us any actual chafing). As for breathability, we’d classify it as good but not great – the Arcon feels marginally more stuffy than the two other guards in this test, despite being equipped with laser-cut holes on the side of the front panel.
On the trail, we were impressed by just how well these guards stay in place – the pre-formed shape works great on the bike, and the Arcons really do a good job of remaining where you placed them. They are easy to pedal in, remarkably so for a guard with such a tight fit and with so much protection on offer. They don’t really move around no matter what you get up to on the bike, and a couple of crashes while riding in these showed that the main protective pad is trustworthy. Of course, as with the DHaRCO guard, the level 2 CE certification comes with the promise that they will indeed do their job even in a more demanding crash scenario.
The quality of construction is excellent, and although a certain focus was placed on breathability, ION has still stuck with fairly sturdy fabrics which has translated to good longevity. We’ve had these guards running for over a year now, and they still look fairly fresh despite a few close encounters with nature. Overall, we are well pleased with the Arcon LTs, they certainly feature near the top of the list of our favorite guards that seem ready for slightly heavier duty. The fact that they may also be better for the environment is the cherry on the cake!
| Where To Buy | |||
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Free shipping on orders over $69 (continental U.S. only).
International shipping available. Some exclusions apply. |
Free shipping on orders over $69 (continental U.S. only).
International shipping available. Some exclusions apply. $114.99
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ION ARCON LT Knee Guard Black, S
$114.99
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Free shipping on orders over $50 (continental U.S. only).
International shipping available. Some exclusions apply. |
Free shipping on orders over $50 (continental U.S. only).
International shipping available. Some exclusions apply. $119.99
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What’s The Bottom Line?
The three guards tested here all belong to the same design category: soft-shell protection that you can pedal with, and that will still do a good job when you crash. Whilst each guard is built around a similar type of viscoelastic insert, there are also some differences worth taking into account when picking one over the other. The Fox Enduro Pro is the lightest and “flimsiest” guard in this test (we don’t mean that in a bad way, just that it is the thinnest and most flexible). As such, it also offers the least amount of coverage, and the Koroyd insert is the only one that is certified to CE Level 1 only. It breathes well and will make itself forgotten pretty much as soon as you start riding. The DHaRCO Gravity Knee Pad provides a step up to Level 2 CE protection, and it also adds lateral inserts for extra cover along the sides of the knee joint. It still breathes at least as well as the Fox Enduro Pro, and it has proven itself to be very comfortable during long days out too - DHaRCO has really delivered for their first-ever protection product. Finally, the ION Arcon LT; it provides extended coverage thanks to a significantly larger viscoelastic insert, and it also addresses upper knee protection with an extra insert in this area. The overall construction is the sturdiest in this test, and that also translates in terms of less effective heat management. Don’t get us wrong, this is still absolutely a guard for pedaling around in all day, but the fit and feel is slightly more “involved” than the other two.
All in all, three worthy options, and we are happy to be spoiled for pedal-friendly protection choice these days.
About The Reviewers
Johan Hjord - Age: 52 // Years Riding MTB: 20 // Weight: 190-pounds (87 kg) // Height: 6'0" (1.84m)
Johan loves bikes, which strangely doesn’t make him any better at riding them. After many years spent practicing falling off cliffs with his snowboard, he took up mountain biking in 2005. Ever since, he’s mostly been riding bikes with too much suspension travel to cover up his many flaws as a rider. His 200-pound body weight coupled with unique skill for poor line choice and clumsy landings make him an expert on durability - if parts survive Johan, they’re pretty much okay for anybody. Johan rides flat pedals with a riding style that he describes as "none" (when in actuality he rips!). Having found most trail features to be not to his liking, Johan uses much of his spare time building his own. Johan’s other accomplishments include surviving this far and helping keep the Vital Media Machine’s stoke dial firmly on 11.
Nils Hjord – Age: 21 // Years Riding MTB: 13 // Height: 5’9” (1m80) // Weight: 185-pounds (84-kg)
Always committed to having fun on his bike, Nils likes to keep his wheels in the air almost as much as on the ground. Although he enjoys going fast and is no stranger to burping his tires off the rim, he has dedicated most of his riding time to mastering manuals and making his tabletops flatter – but that doesn’t mean he can’t put the hurt on his wheels through a high-speed rockgarden too, when needed. Good thing his dad is a full-time Vital staffer with access to lots of bike parts that need testing!
Photos by Johan Hjord and Nils Hjord
9/11/2025 9:07am
View replies to: 3 Knee Guards Compared: Fox Enduro Pro, DHaRCO Gravity, and ION Arcon LT
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