New G-Form Terra Mountain Bike Knee Guards feature “fully biodegradable and 100% recyclable” technology

The new G-Form Terra mountain bike knee guards are the most secure and most comfortable knee pads I've ever worn.
Photo: Christine Henry

G-Form made a name for themselves as one of the first companies to sell flexible mountain bike pads that were comfortable enough to wear while pedaling all day. In recent years, the company has completely redesigned their product line and now offers a host of pad and guard options across multiple lines. G-Form has also expanded into other sports and found success by tailoring their flexible, lightweight pads for a whole host of applications.

I recently had the chance to put a pair of their latest Terra Knee Guards to the test.

Photo: Greg Heil

G-Form Terra Mountain Bike Knee Guards key specs

  • RE ZRO eco-friendly material
  • Certified at CE EN1621-1 Level 1 protection
  • Weight: 290g/pair
  • Price: $109.99
  • Buy from JensonUSA

It had been a few years since I’d last worn a pair of G-Form pads, and the all-new Terra Line has shattered my expectations of what the brand has to offer. First and foremost, the Terra line features padding with “RE ZRO eco-friendly technology.” These “fully biodegradable and 100% recyclable” pads are designed to “biodegrade in an estimated 3-5 years if they were to end up in a landfill,” according to

To accomplish this, RE ZRO developed the pads with TOTO-TOA® technology. “This allows microbes and fungi to enter the molecular structure in a landfill environment and break down the plastics, leaving nothing left and returning to zero,” according to

Many people ask if this means that the padding will biodegrade over the life of the knee guard. In short, the answer is “no.”

“In order to start the biodegradation process, the RE ZRO parts must be in an oxygen-depleted, microbe-rich environment such as [a] landfill, so you can rest assured that whilst the armour is in your garment, it is doing its job and keeping you protected,” writes RE ZRO.

Photo: Greg Heil

While sustainability was RE ZRO’s primary focus, they “also wanted to achieve all of this without any compromise on performance.” The pads are flexible and lightweight, and they’re also ventilated to allow air to pass through the pad and cool the knee.

G-Form is quick to note that while the outer fabric is machine washable, you’ll need to remove the purple RE ZRO padding and wash that portion by hand.

As for the design of the overall guard, the Terra is much longer than G-Form pads I’ve used in the past. The long upper and lower portions of the sleeve cover a greater area of the leg, and the upper features a heavy-duty rubber gripper.

Photo: Christine Henry

Out on the Trail

My standard M.O. for big mountain rides is to let my pads ride around my ankles as I grind uphill for a few hours, pull my pads into place at the top, then rip back down the mountainside. The Terra’s long fabric uppers and lowers can feel a bit bulky when they’re down around your ankles. However, the pads aren’t designed to cover your ankles — they’re designed to stay on your knees.

It can take a bit of work to pull the Terras into position, but once there, the heavy-duty upper rubber gripper locks down solidly onto the skin. The long upper also means that the pads will run up under the rubber gripper on your bibs, providing a second level of security. Other pads I’ve used in recent years have been so short that they might not necessarily overlap with bibs, which means that they’re not nearly so secure.

The lower cuff also has a rubber gripper, but it’s lower profile, which allows it to slip on more easily.

Photo: Christine Henry

After a few months of testing, I’ve found the Terras to be the most solid and immovable pair of pads I’ve ever worn — full stop. This solid connection and the difficulty of moving them up and down has led me to wear my pads more than ever before while pedaling through rolling terrain and up short climbs. Even when riding in these pads for over an hour, I’ve experienced zero movement or slipping of the knee guard.

Even the most breathable pad is hotter than wearing nothing, but the Terra does everything it can to disperse heat. The RE ZRO pads allow air to pass straight through the purple padding thanks to their ventilated design. G-Form’s fabric sleeves are cut away behind the knee to increase ventilation and decrease binding while pedaling — a change from previous models I’ve tested. I found the cutaway design to mesh perfectly with my personal anatomy, even though my legs are generally shorter and more muscular than the average mountain biker’s.

I have not yet crashed on the Terra knee guards, and I’m not committed enough to this review to lay it over on purpose. However, kneeling down in the dirt and accidentally knocking my knees on my bike have shown me that the pads provide great coverage, including plenty of wrap-around coverage of the knee. This is yet another improvement over previous models, which didn’t block glancing side blows all the time.

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The only complaint I have is that some of the G-Form logos began to peel off, but this could be because I tested a pre-production pair of pads. According to G-Form, the only change that they made for the production pads was adding “a slightly more durable outer cover.”

Pros and cons of Terra Mountain Bike Knee Guards


  • Stay firmly in place while pedaling
  • Biodegradable and recyclable
  • Well ventilated
  • Comfortable


  • Difficult to pull into place quickly
  • No right/left indicators on pads
Photo: Christine Henry

Bottom line

I’ve used a variety of different models and brands of knee pads over the past six years, and none of them were good enough to make it into my “Torture Tested” roundup. But after testing the latest Terra mountain bike knee guards from G-Form, I think I’ve finally found my pad! These are the most comfortable, most secure mountain bike knee pads that I’ve used to date, and I plan to keep using them for months (or even years) to come.