Wil reviews the CushCore inserts on his Giant Revolt X gravel bike
Hold on a moment, CushCore on a gravel bike?
I’ve been using CushCore inserts across a load of test bikes for quite a few years now. That’s included the original Pro inserts on numerous trail and enduro bikes, the big Plus inserts on fatter-tyred e-MTBs, and more recently the new Trail insert on my custom steel hardtail. I’m also a convert for using the lightweight XC inserts on hardtails and full suspension race bikes, to the point that I always fit one in the rear wheel before ever stepping foot out of the workshop.
Given the drastic reduction in punctures and enhanced grip that CushCore brings to the party, I’ve been curious about trying them out on my Giant Revolt X. It’s already quite a smooth-riding gravel bike thanks to its Fox 32 TC suspension fork and 50C Maxxis Rambler tyres, but I’ve always been a little concerned for the lightweight carbon rims when bombing down rockier singletrack. I’ve also been eager to see what other benefits CushCore could offer on a gravel bike, other than just enhanced rim and tyre protection.
CushCore XC / Gravel Tubeless Tyre Inserts
- Weight: 122g (gravel) – 148g (XC)
- Price: $145 AUD (single) – $268 AUD (pair)
These days CushCore produces a huge variety of different tubeless tyre inserts. The lineup features Plus, E-MTB, Pro, Trail, XC and Gravel models that are all made from the same high-density, closed-cell foam material, but feature unique profiles that are designed to suit different width tyres and rims.
Initially I was going to seek out the Gravel inserts for the Revolt X, but upon looking at the specs I realised these would be too narrow for the 25mm inner rim width and 50C tyres. With those dimensions, the slightly wider CushCore XC inserts would provide the necessary coverage over the rim’s hookless beads.
There’s not much of a weight penalty either, with the XC inserts weighing 26g more per wheel compared to the skinnier gravel inserts. Even still, both inserts are still lighter than a conventional inner tube.
Regardless of the model, CushCore sells its inserts either as a single or as a pair. Included in the box is CushCore’s own tubeless valve that features a drilled base to prevent it from being smothered by the insert.
Installation
I fitted the CushCore inserts to both the front and rear wheels on the Revolt X. I’ve had some real battles with tubeless inserts over the years, but installation in this case was refreshingly easy. In fact, I was able to do it all by hand with no need for a tyre lever.
The CushCore inserts do have a tight fit over the rim, so you’ll need to stretch them slightly when first fitting them to each wheel. The snug fit pays dividends on the trail with no rattling around inside the tyre like you can get with flimsier and lower-density foam inserts. I’ve found the CushCore inserts last a lot longer too.
Fitting the Maxxis Ramblers around the inserts was straightforward, and after adding a few glugs of Champions Choice sealant I was able to inflate both tyres with a regular floor pump.
On the trail
Prior to fitting the CushCore inserts on my gravel bike, I’d been running around 30psi in the Maxxis Ramblers to support my 67kg riding weight. With the inserts fitted, I’ve been able to drop those pressures right down. Like, way down.
After some experimentation, I’ve settled on just 22psi in the front and 24psi for the rear. This has led to an incredibly smooth ride quality, with the softer tyres helping to absorb more irregularities on the trail. The thick foam inserts also serve to dissipate high-frequency vibrations, and that improves the overall damping characteristics of each wheel. The end result is more grip and better comfort on longer rides.
At those pressures there is a touch of squirming from the rear tyre when really loading the bike up into a sharp corner. But with the CushCore insert wedging the tyre beads snugly into the rim, there’s very little risk of any burping. Anyway, if I know I’m heading out to ride smoother dirt roads and mixed surfaces, I’ll just bump up the pressure a couple of psi to firm things up.
Any downsides?
You do notice the extra 300g of rotational weight, though not all the time.
I haven’t found the Revolt X to be quite as snappy when accelerating from a standstill, and when I’ve been climbing up steeper singletrack you can tell there’s more inertia to overcome during slow-speed technical manoeuvres.
At cruising pace however, I’d be hard pressed to tell the difference compared to running no inserts at all. The way the inserts effectively quieten down general chatter also helps them to fade into the background, and since they sit quite low down inside the tyre cavity, they don’t seem to impact on the casing’s compression. While some of the bigger volume inserts on the market have a habit of making tubeless tyres feel weirdly stiff and wooden, CushCore allows the tyre casing to retain its suppleness.
Add in the smoother ride, improved grip and added protection for the tyres and rims, and for me the benefits easily outweigh the cons.
Flow’s Verdict
I’ve been thoroughly impressed with the CushCore inserts on my Revolt X gravel bike. They bring about a noticeable improvement in vibration damping, and the added protection means you can get away with significantly lower pressure for enhanced grip and comfort.
While they offer benefits for any off-road bike, they’re a particularly useful upgrade for riders who own a bike with limited tyre clearance. If you’re looking for more compliance but your frame and fork won’t accommodate higher volume tyres, CushCore inserts will be an effective alternative.
Of course they’re still not for everyone. If you’re typically riding on smoother tarmac and ‘champagne gravel’, you’re unlikely to benefit from the added comfort and puncture protection. Weight sensitive riders are also likely to scoff at the extra 120-150g per wheel.
To put things into perspective however, that’s only about the same as a conventional inner tube. If you can handle that, and you use your gravel bike as a proper all-terrain vehicle, I can highly recommend trying out a tyre insert like CushCore.
