You’re approaching a water crossing. Dozens of tire-killing rocks lie in wait, hidden beneath the water. The riders around you drag their brakes and carefully tiptoe across. But you — you charge in at full speed because you have a secret weapon: CushCore.
At tough gravel races like Unbound Gravel, that scenario plays out over and over again. Catastrophic rim-outs and punctures are common. When it gets chunky or gnarly, riders have to move at a snail’s pace or risk pinch flatting. That is unless you protect your wheels and tires with a tire insert. I added a set of CushCore’s Gravel.CX inserts to my gravel bike this year, and it was the best decision I’ve ever made. Here’s why you should consider adding some to your own gravel bike.
What is CushCore Gravel.CX?
CushCore's distinctive green valve means go right ahead and don't slow down!
CushCore is the most popular brand of mountain bike inserts, and now they’re gaining a foothold in the gravel scene with gravel- and cyclocross-specific inserts. We’ve already written an in-depth post explaining what tire inserts are, but here’s the quick and dirty version. Tire inserts enhance tubeless wheel and tire systems by offering rim and tire protection as well as damping. The insert is a ring made of closed-cell foam so it doesn't absorb sealant while it sits inside the tire.
CushCore Gravel.CX specs
- Wheel Size: 700c
- Compatible Tire Widths: 33mm-46mm
- Compatible Inner Rim Widths: 19mm-26mm
- Weight: 110 grams (per insert)
- Full kit includes 2 inserts, 2 44mm tubeless valves, valve core tool, installation instructions, and rim stickers.
CushCore Gravel.CX inserts pros
- Protects tires from pinch flats
- Protects rims from damage due to rim strikes
- Allows riders to run lower tire pressures
- Supports tire sidewalls during cornering
- Supports the tire bead to prevent burping
- Provides extra damping on rough terrain
CushCore Gravel.CX insert cons
- Additional weight
- More difficult tire installation
- Can complicate flat repair
CushCore Gravel.CX review
This illustration shows CushCore Pro in action, but the principles are exactly the same for CushCore Gravel.CX. Photo courtesy of CushCore.
I’ve been using CushCore inserts in my mountain bikes for years to protect my expensive carbon rims and prevent ride-ruining punctures. But my favorite attribute is actually the additional comfort. CushCore inserts take up about half of a tire’s volume, acting as a damper for the air “spring” inside the tire. This, combined with the significantly lower pressures you can run (around 5psi lower) helps mute chatter and impacts on rough terrain.
Despite these benefits, it took me a long time to commit to using CushCore’s gravel-specific inserts. There was one thing holding me back — weight. CushCores are among some of the heaviest inserts available. The claimed weight for the Gravel.CX model is 110 grams per insert. On my scale, my inserts weighed 118 grams and 120 grams. That’s half a pound! And it’s all rotating weight — the worst kind. Though I have no problem turning my mountain bikes into tanks because they get abused on trails, the idea of adding a half-pound to my gravel wheels made me queasy.
CushCore Gravel.CX helped me finish Unbound Gravel with no punctures. The extra traction was helpful in the mud too!
But that all changed after I got an entry into Unbound Gravel this year. The world’s premier gravel race has a reputation for shredding tires and crushing dreams with sharp and chunky flint gravel. To make it to the end of the 200-mile race, you need a robust wheel and tire set-up. I decided to add CushCore to my set-up when I discovered that last year’s winner, Ian Boswell, ran CushCore Gravel.CX on his own bike. And now, most top competitors are running CushCore or a similar insert. That’s all the proof I needed to make the leap.
My hands and sit-bones used to feel beat up after long gravel rides, but after a 200-mile day on CushCores, I was stunned at how good I felt. The extra damping paired with extremely low tire pressures made a serious difference in my comfort. The best part is I suffered ZERO, that’s right, zero punctures. I had several violent rim strikes, mostly in water crossings. And while I saw many competitors flat, I was able to blast through every water crossing at full speed with no issues. CushCore confidence is massive.
As for the weight, I honestly forgot the CushCores were there. While Unbound does have some very steep, short climbs, I think the extra traction of lower tire pressure outweighed any weight penalty. If your local rides feature more long, extended climbs, then it may be worth considering a lighter insert like Tubolight. But in my experience, no insert feels as supportive and protective as CushCore.
Is CushCore Gravel.CX easy to install?
CushCore Gravel.CX is the easiest CushCore to install, and if I'm being real, 110 grams feels very light when I'm actually holding them.
A big concern with many riders is the ease of installation. CushCore has a reputation for being difficult to work with. When I compared CushCore Pro vs. CushCore XC I rated CushCore Pro an 8/10 for installation difficulty, and CushCore XC 5/10. On that same scale, I’d rate CushCore Gravel.CX a 4/10. (1/10 is the easiest tire install you’ve ever experienced, 10/10 is impossible to mount.)
If you already have some experience installing tire inserts, you might even consider it a 2/10 difficulty. The CushCore Gravel.CX insert is significantly smaller and stretchier than its MTB counterparts, so it’s much easier to squeeze into a tire. If you have no experience, there may be a steep learning curve. Watch CushCore’s install videos for tips and be patient. Once you learn the technique, installation and removal become significantly easier.
What if you puncture with CushCore Gravel.CX?
Sometimes, you get a puncture that tubeless sealant just won’t seal. In that situation, simply use a tire plug to repair the puncture. But what if tire plugs fail too? This is a big concern with riders new to inserts.
First, I want to say that a puncture this catastrophic is rare. Tire plugs are extremely effective and reliable, and since adding CushCores to my bikes, I actually don’t ride with spare tubes anymore. If the worst does happen, and my tire won’t hold air, my plan is to just limp out on the insert.
However, in a race situation like Unbound, I carry at least one spare tube. If you have to perform an emergency repair with a tube, you’ll need to remove the CushCore first, which can be a hassle. Fortunately, as I’ve already said, this scenario is VERY unlikely.
CushCore is perfect for my local gravel.
So Unbound Gravel is over and I “beat the sun,” but the CushCore Gravel.CX inserts remain in my tires. At $150 for a set, they can feel pricey, but for me, CushCore was the one upgrade that made the most noticeable difference in my ride. My local gravel rides feature lots of rough, washboard roads and the occasional chunky singletrack trail. For this type of terrain, the extra puncture protection and comfort CushCore provides are simply too good to give up.