Foam Inserts for gravel riding

Since the possibility to comment on articles closes after 2-3 weeks I am going to open up a thread about this here in the forum. Hope that’s OK…

I went ahead and pulled the trigger on a set of Cush Core XC/Gravel foam inserts based on this CT article

I agree with some of the comments there that you might as well go with a MTB hardtail if you’re taking it that far on gravel…
BUT I also have a gravel bike which i LOVE to ride (additionally to my MTB) on much of my MTB trails + on road as well. If I push it a bit too much on said trails I sometimes get some cringe-worthy impacts and situations. (I have to add that I have an extra set of wheels on 28mm tyres If I know I’ll ride it mostly on road)

This article now finally convinced me to give inserts a try - (running 700x40 tyres)

First update (re:mounting! re: riding experience to follow by the end of this week hopefully - pretty busy work-week with too little bike-time on the horizon😭):

I immediately mounted them today right after they were delivered. Also, I finally had an excuse to pull the tyres off my rims in order to ditch those extremely crappy valves that came with my Roval Terra CLs. (A sidenote, in case the Specialized-PM who spec’d those valves should ever happen to read this [I doubt it] : those valves are complete rubbish!)

As someone who’s been running tubeless on MTBs for aprox 15 years (started off with MAVIC USTs and have tried a few different brands since), who’s been running tubeless on road bikes for the last 3 years (hookless and hooked, different wheelsets) and who’s therefore had quite an array of good and bad experiences mounting tubeless setups, I must admit that it took a bit longer than expected at first but once you get the hang of it, it’s absolutely doable.

IMHO in order to mount such liners in my case the Cushcores) without having to go get a gorilla from the zoo to pry them onto the rim there are three things which are imperative:

  1. Pushing the tyre’s bead well underneath the cushcore so as to produce enough slack to more easily pop the tyre onto the rim (thus preventing you from destroying your rims due to employing too much brute force - it’sd doable, don’t ask me how I know…)
    Using soap water in order to make the bead pop back out more easily

  2. Having a high-volume and high pressure pump to pop and set the tyre onto the rim (I have a compressor at home, but there are other solutionsout there) before you proceed to re-releasee the air in order to top it up with sealant.

  3. When in doubt, take the time to look into the brand’s video tutorial on how to do it properly - there’s some pretty valuable and specific pointers to be found in that video.

As someone who genuinely enjoys the wrenching part of cycling I can recommend also trying this to anyone who is handy when it comes to doing repairs on their bike. However, if you’ve never set up a tubeless tyre/wheel combo before, I strongly suggest you go to your LBS to get this done!

Riding update to follow this week or next.

Feel free to add your 2 cents about this here


Great post. I too pulled the trigger on some cushcore inserts - in my case, the 27.5 / 650b ‘XC’ ones. The reason I went with those in particular was 1) the size: I need them to fit 650b x 48 tyres on 25mm internal width rims (that’s 27.5 x 1.9 i think) and 2) not being too heavy. The ‘XC’ inserts are meant to be a bit lighter than the usual ones - I think Caley actually used these and recommended them too (I saw after ordering them).

I had looked at the Panzer inserts too - they look nice and light but I can’t see any that would fit my tyres (at least not availble to me).

To research this i read the CT articles and also a good roundup of 6 different inserts on Pinkbike. Worth a google and checking that out. That article was MTB focused so didn’t have sizes relevant for Gravel (Capital G Gravel).

The reason I made the decision was that when I get down towards 20psi on my wheelset i do feel significant ‘squirm’ which is pretty disconcerting. I’ve ridden some pretty wild forest trails where traction was an issue. Usually i’m commuting on paths so 30psi is fine (and inserts not needed) but as we’re coming to winter… let’s experiment.

I’ll post on my experiences here as well.


That’s always the same story. When do your gravel bike stop being a lightweight roadish thing that can still do a bit more and end up being a XC bike.

I decided to draw the line with the dropper and insert. I like my gravel bike to still have that lightweight and springy road bike feeling, even with 27.5plus wheels. If I feel I would be more comfortable with a dropper and insert I take one of my mountain bikes. It would be way different if I had chosen to limit the number of bikes in my stable and not kept the mountain bikes.

Anyway I like going randomly into unknown path and will sometimes end up in something where I would like a more trailish bike, I just accept I need to be more cautious and go slower if I am riding the gravel.

“BUT I also have a gravel bike which i LOVE to ride (additionally to my MTB) on much of my MTB trails + on road as well. If I push it a bit too much on said trails I sometimes get some cringe-worthy impacts and situations. (I have to add that I have an extra set of wheels on 28mm tyres If I know I’ll ride it mostly on road)”

Couldn’t disagree more….the advantages of an insert are more than just providing some added protection when running low PSI….biggest among them being able to continue riding if you get a flat. I’m doing Big Sugar later this year and will absolutely run inserts for that event.

Add in better traction, improved cornering with lower psi, etc and there is a solid case for gravel inserts beyond rim protection if you are under-biked.


I tried to mix CushCore inserts, Roval Terra CLs and 38” Panaracer Gravel King SK Tires. I spent a better part of a week trying to install the tires over the CushCore. I watched all the YouTube videos, used soapy water, etc… I finally decided to throw in the towel. The LBS was successful but implored me to never ask them to do it again. I have set up tubeless previously on road and gravel wheels without any issues.

I have a pair of 43” Panaracer SK+ tires ready to install before Unbound In June…I can’t see it going well unless the wider tires are easier to install.

I have a Tufo Speedero up front and a Maxxis Rambler in the back (both 40s) on my Rovals.
The install wasn’t easy but it’s doable if you take your time


There is a solid case for inserts in literally every tubeless application. They enhance the operation of tubeless systems and add no real negatives, arguing that it’s only an extreme use application is just an admission of ignorance or inexperience with actually using inserts.

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Very timely. My Vittoria air liner inserts should arrive tonight. Also preparing for Unbound (100 only!) in June. I am going to run either Specialized Pathfinder Pro in 38C or Pirelli Cinturato M in a 40c. Planning to experiment with the liners with both tires before. Rims are Hunt Gravel X-Wide (25 mm) internal. Back-up are the DT-swiss Gravel LN that came on the Canyon Grail AL

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For me, the biggest benefit I can see is the ability to run a really low pressure (particularly if you’re a larger rider - I’m 80kg).

I rode with a mate at the weekend, both riding Pirelli M 45mm - he had inserts in both tyres and I didn’t. He was able to run around 20psi (compared to my 30psi) and he coped with the mud (I’m in the UK) noticeably better than I did and maintained traction when my wheels slipped.

I bought some Vittoria inserts as soon as I got home…

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Just installed the XC inserts on the weekend. Had one ride to test - too early to give a verdict, though I felt very smooth and planted on a mix of surfaces it could be in my head . The inserts aren’t really that heavy.

Installation wasn’t too bad really. I watched a couple of videos and the instructions are pretty good. The valve cores are nicely made. Getting the insert on the rim wasn’t too bad - as with installing a tyre with no levers, start on one side and work towards the other, using gravity to help you. Getting the tyre onto the rim wasn’t too bad etiher - though gloves were a big help. I would say if you can fit some gloves in your riding kit somewhere that’s not a bad idea. I’ll have to report back on ride feel and if I ever need to swap in a tube on the roadside.


Foam inserts are great for gravel bikes, I initially fitted them to 650b wheels for a 10 day bikepacking trip last year. I knew some of the route, The Great Glen Way and The West Highland Way, would be a bit rough and with bags and panniers, the bike wasn’t the nimblest when it came to avoiding rocks, ledges, steps etc.
I used Rimpact foam inserts and I recently fitted another set into a set of 700c wheels after seeing how well they worked last year.
Plus if anyone says they are not for gravel bikes, its my bike and my rules…

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I’d say that, based on today, the pro riders need to look into foam inserts for Roubaix if they really want to run tubeless. WAY more flats than normal it seems……my guess is that it is more a burping issue vs. punctures.

But if they were running inserts, it at least let’s them keep going to get to a team helper.

Agree that gravel can benefit with inserts. Ive been running cush core xc inserts in bith 42 and 52 tires. If im running low pressures, burp is a lot harder and if i accidentally hit a square root too hard, my rim survives.

The weight isnt insignificant. I think I’d rather go with smaller tires and proper gravel inserts. The rim protection and flat protection can definitely be worth it. If i had my choice I’d purchase tannus tubless armour. They are much lighter, give great flat protection and i dont think the sidewall support is as big a deal as it is mountain biking.

I’ve pedalled 15km on a rear flat on my insert without any damage to the rim or tire.

In terms of installation, gravel inserts are easier than mtb. If you cant install a regular tire without levers, get some help with inserts. It definitely ups the difficulty. A plugging kit will usually get you home so removing the insert with a flat is rarely an issue.

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