Tire inserts for XC racing


I was reading on another group that foam tire inserts are quietly taking over the top ranks of XC racers for the low pressure support/traction and pinch flat protection benefits despite the added weight. The most commonly mentioned brands are Nube, Pepi sticks, barbieri, and DIY closed cell backer rod.

Have any of you experimented with these? What were your results?

My application is XC / XCM racing. Currently running Nobby Nic / Racing Ralph 2.25” with sealant at 17/18psig and I weigh 138lbs.


following… been interested in this

Well…I’m one of the frequent posters on the thread you’re mentioning. I also happen to be the person that was posting heavily in the AC Separation thread which occurred on the second ride with my tire inserts in my bike :frowning:

So anyway. My wife has been running 1.5" closed cell DIY inserts in 2.25 and 2.35 tires. They run abotu 60 grams per tire if you do the DIY or Nube, Pepi, etc. If you go with the CushCore XC version they add 100g per tire which is just plain dumb.

They are a game changer from what she is saying. We are able to run 2-3 psi less in the tires but when she hits square edges it actually feels like the tire “pushes” you over the ledge. Because the tire doesn’t deform as much and has support from the insert it increases the ramp rate of the tire kind of like using tokens in a fork. She has more grip on loose stuff but has more bottom out protection, i.e. best of both worlds.

The DIY version can be had for around $7 per set if you buy enough to make some with friends (shipping sucks). 1.5" works great for 2.25 - 2.35, 2" is too big unless you use something to chop the top half of the rod off. If you’re looking at them I’d recommend making your own vs buying anyone else. They are a consumable items as they can rip if you pinch them on a rock. At the price most of these companies are charging it just doesn’t make sense to buy theirs when you can create your own with a hot glue gun and Tyvek tape. We just bought 1 1/4" to make some for tubeless cyclocross which I think could be the bees knees for making burp and bottom out resistance even better for tubeless.

One other thing they do is provide roll over resistance for the tire at lower pressures. So we are running 16/21 at about 160 lbs on 2.25 tires and could probably go lower, just testing them now.

Hope that helps.


Hmmm… this is pretty interesting. Is this the kind of stuff you’re using?

Yes but best pricing at www.bestmaterials.com

About 81 inches per tire so you have to add about 9” to the 72” sticks they sell.

This is what I bought. https://www.amazon.ca/dp/B00269N258/ref=pe_3034960_236394800_TE_3p_dp_1

There is probably a similar link for the American Amazon. Mine just arrived today - looks to be enough to do 7 or 8 sets of wheels. I can confirm that this stuff is visually indistinguishable from the barbieri product.

I was reading that you have to get the closed cell stuff. The open cell stuff sucks up your sealant faster than a .

I’m heading off to BCBR tomorrow- my testing will have to be later in July.

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Thanks @trevorrr and good luck at BCBR! You still a fan of the Sniper?

I can 100% confirm that cushcore is nothing like DIY pool noodle foam, there is no comparison between the two. And could you really notice 40g difference per wheel? I doubt it.

I’ve seen DIY pool noodle foam completely destroyed after only a handful of rides, sure it’ll protect the rim for a couple of runs but thats about it. I’ve handled the Nukeproof versions, the Rimpacts and now the cushcores too and they are all seriously different products.

All I’m saying is that I don’t think its fair to slate them when some of the specifically R&D’ed versions really are not “closed cell pool noodles”.

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I think we’re talking different things here if you’re seeing the DIY versions “destroyed” after a few rides. The title of the thread is “Tire Inserts for XC Racing”. If that is the case I don’t think you’re talking about XC or XC Marathon racing; more Enduro or Trail riding. For the XC crowd I don’t see inserts as a way to plow through things without destroying the tire or the rim, rather I see them as a way to run lower pressure, get better grip, and provide support to PREVENT bottom out.

I appreciate the R&D and for the trail/enduro crowd I’m sure they make more sense. The reason I’m saying they missed the mark is it is an easier sell to add 40-60 grams per wheel vs adding 100 grams per wheel and paying $150 per set. There are people out there in the XC race crowd that won’t use a dropper, buy aluminum bottle cage bolts, don’t carry a tube, ride hard tails, and many many more things to lose weight on their XC race bikes. You are going to be very hard pressed to get an XC racer to add 200g of rotating weight back to their bike, even 80g per wheel. Hence I say try the DIY version first and save yourself a ton of money. If you’re casing them after 2 rides then go for something heavier duty if you see value; but to spend $150 up front on something you’re not sure you will like and adds 200g to an XC race bike makes no sense to me.


Yeah ok, you totally got me there, I was absolutely coming from the trail/enduro side of things and just applying that across the board. Fair cop. :flushed:

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This is from last week end, XCM race in the Alps. Classical snake bite despite running an insert. Last descend before the finish, happened to the rider in the lead. Lost the top spot and came in second. Fixed it with Maxalamis.


Loving the Sniper so far. Did the Spakwus 50 / 35 races two weeks ago and it performed flawlessly. At least as capable as my Ripley/Pike and 1.5lbs lighter for the climbs (not including tire inserts!)

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One of the interesting things in this space is that we may end up with totally different solutions for each application. Remember when we were all starting to experiment with single ring drivetrains?


OK, I “built” and installed the inserts following some instructions I read on the other forum. 1 1/2" closed cell backer rod from the link above. This came in 6’ sections, so I had to add a ~9" length to the 6’ one to get the right length for a 29er. I might do it 8.5" next time as it fit the rim a bit loose. I attached the sections using zip ties and duct tape. The whole insert came to 56g (per wheel).

The valves I used are Barbieri (https://r2-bike.com/BARBIERI-Valve-Set-2-Pieces-tubeless-Carbonaria-universal-Version-20-35-mm ). They have a channel for the air to go out the sides rather than straight into the insert.

The installation on my wheel/tire was super easy - in fact, I’m not always able to get the tubeless to seat with my crappy floor pump (often resort to the compressor) - this time I got both tires on with the floor pump. I have them inflated to 16psig at both ends as measured by my Schwalbe digital gauge.

Setup is: Light Bicycle XC925 rims (30mm external), Schwalbe 2.25 Nobby Nic / Racing Ralph.

And - how do they work? Pouring rain today, will hopefully get out tomorrow.


Update: I was able to ride the course in Winter Park that my wife was racing on (I can’t race yet after surgery). I was using 1 1/2" back rod inserts with a Ikon 2.35 up front and an Ardent Race 2.25 rear. Running 21R / 16F. Course had sections of roots, round and square edged rocks and also some loose descents with 4-6 inch rocks rolling around. I ran 2 psi less than I normally would on this course with those tire sizes and I definitely could tell the difference.

I felt like I had 1/2" more suspension with the lower pressure and more grip, but the tire never got close to dinging the rim when I went over a sharp edged root or rock. It felt like you get the grip of having more tire on the ground but you get better fold over and snake bite resistance. As the tire deforms closer to the rim it is supported by the insert and acts to increase the ramp rate. I really liken it to adding tokens to your fork. You can run lower pressure to get better small bump compliance but as your go deeper in the tire travel you get progressively more resistance to bottom out.

It also gives you support when climbing seated and you go over a root or a rock. Almost as if it is pushing you up and over it. I think this is because the tire isn’t conforming as much to the rock or root and getting stuck on it as you pedal over.

Anyway that was my first true ride on it and I’m sold at this point on the idea. I didn’t notice any rolling resistance difference in the flat or fire road sections and there was a section of this trail that is flat’ish, fast, and had roots across the trail. I was able to stay seated even more than normal on my Scott Spark and just motor through these sections without as much unweighting of the saddle when I came to a rooty section.

your mileage may very depending on that way you ride. If you’re bashing your way through everything you might need to go with a heavier duty insert like a Huck Norris or Cushcore. But for my I ride lighter on the bike so it works great for me.

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Ha, the tokens in a fork analogy is something I thought of yesterday and was going to post but never got around to it. Of course the foam is a bit compressible, and probably has a spring rate of it’s own, but it’s a great analogy.

I’m going to try mine out tomorrow. I hope to get as good results as you did. Although I think we’re riding the smoothest trail in Alberta.

What sealant?

Stan’s regular sealant.

OK, got out for a few good test rides on the inserts. I normally run 16-17 psig, set it to 15 psig with the inserts. The front 2.25" Nobby Nic is still in good shape, but the rear 2.25" Racing Ralph is getting quite worn down.

First was two hours on a smooth flowy trail (High Rockies Trail in Kananaskis for anybody familiar with Alberta). It had rained two days before, and the trail was in perfect condition. The tires felt like velcro, but really anything would have probably been good enough due to the nice packed nearly-dry trail. Some high cornering force berms at the end, no sign of roll-over. No extra noticeable rolling resistance. So far so good.

Second ride was two hours - one of the hardest technical climbs in Alberta, followed by a quite-rocky fast descent built by DHers (Pneuma to SHAFT on Moose Mtn). I would normally see 15 psig on this trail as a recipe for busted carbon rims. On the climb, I cleaned two sections that I had never successfully done before. On the descent, I set a “moving time PR” (not a real PR - had to stop and wait for someone twice) on the segment by a significant margin. It didn’t feel like a was riding too low pressure - I just had more grip.

I’m impressed with the results so far. Will continue on with this and get some really good testing done next week in Revelstoke.


One thing I would suggest to people is to weigh the wheel after set up with an insert and sealant. Then a month or two later, check sealant level and see if you need to add more sealant.

I have the Anacondas and I may have a made a mistake with the measurements, but it seemed like as if the closed-cell insert absorbed some of the sealant and there was practically no sealant left in the tire so I had to add more sealant. Ultimately, the weight increase from using the insert was more than double the weight of the insert due to the need to use more sealant.

It would be interesting if someone else could do similar measurements and replicate (or not replicate) my results. After Leadville, I’ll probably put the inserts back in as I love being able to have 4 psi lower in my tires, even with the added weight. The insert saved my arse when I hit rear wheel really hard on a lip of a foot bridge that probably would have resulted in a DNF.

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