Review: Vittoria's 50g Air-Liner Light Promises Run-Flat Protection For XC & Trail
While the hype surrounding foam tire inserts appears to have peaked, they're nevertheless popular, especially among DH and enduro racers. But while they have been seen on cross-country race bikes, the weight has understandably put off riders who prioritise climbing speed.
So far, one of the most popular options marketed specifically at cross-country riders is the Cushcorre XC, which weighs in at 150 g per insert. That's not what many XC racers would call a negligible weight penalty. In contrast, Vittoria's new Air-Liner Light comes in at just 50 g per wheel, making it one of the lightest out there - perhaps the lightest.
So far, one of the most popular options marketed specifically at cross-country riders is the Cushcorre XC, which weighs in at 150 g per insert. That's not what many XC racers would call a negligible weight penalty. In contrast, Vittoria's new Air-Liner Light comes in at just 50 g per wheel, making it one of the lightest out there - perhaps the lightest.
Vittoria Air-Liner Light Details
• Intended use: XC, Downcountry, Trail
• Actual weight: 50 g per insert
• Fits tyres 29”x2.1” to 29”x2.4”, rims 25-30 mm
• Claimed run-flat protection
• Price:€ 59.95 (per wheel, inc. valve & lever)
• vittoria.com
• Intended use: XC, Downcountry, Trail
• Actual weight: 50 g per insert
• Fits tyres 29”x2.1” to 29”x2.4”, rims 25-30 mm
• Claimed run-flat protection
• Price:€ 59.95 (per wheel, inc. valve & lever)
• vittoria.com
Yup, it really is just 50 grams.
And in addition to all the usual things you'd expect a foam insert to do (pinch protection, rim protection and sidewall stability), Vittoria claims their insert offers run-flat protection. They say it expands as the air pressure inside the tire drops after a puncture, filling out the tire and making it easier to salvage a race.
When the tire pressure drops, the insert expands to fill the space, as shown in these demos from Vittoria. Vittoria say this makes it possible to finish a race (or just make it to the tech zone) on a flat tire.
This is possible, Vittoria say, because the foam in the insert is permeable to air, so as the tire is inflated, the insert gradually soaks up the extra air like a sponge. When you get a sudden puncture, the foam - still full of pockets of pressurised air - expands to fill up most of the tire, at least for a while until the air seeps back out of the foam. Vittoria says this makes it possible to finish a lap or a race after a puncture. Last season, BMC MTB Racing, Santa Cruz FSA and KTM-Vittoria teams used the insert for XC racing and helped with its development. Vittoria say their insert has already saved the races of some of their athletes.
If you're wondering if this ability to absorb air will cause the insert to soak up all your sealant, Vitoria says it is coated with "a tough waterproof skin which prevents cuts and any absorption of sealant". Though Vittoria recommends its own sealant, they say it'll work fine with other brands.
The Air-Liner comes with compatible valves and specially-designed tire levers.
Installation
I fitted the Air-Liner Light in a 2.4" tire on a 30 mm rim and the process was very straightforward. Though a nice, slim tire lever is included in the box, I didn't find it necessary. Just unseat one of the tire beads, install the valve, pop the insert in so it sits straight, pinch the insert over to the opposite side while re-installing the bead, inject sealant through the valve and re-inflate. With a narrower tire and rim, it may be trickier to install the tire, but the low-density foam makes it much easier than many inserts to install.
Can you really ride with a puncture? (Sort of)
To test Vittoria's claim that the insert will support a flat tire, I fitted the insert in a 2.4" tire and inflated it to 25 psi, then left it for an hour for the air pressure to work its way into the insert. As shown in the above video, I then removed the valve core to simulate a severe puncture. Disappointingly, I couldn't feel the insert expanding to fill the space inside the tire casing, and it was easy to compress the tire or unseat it from the rim bed by hand, much like with other inserts.
So while you could ride like this, gingerly, and the insert will help prevent further rim damage compared to nothing at all, it doesn't seem to support the tire noticeably more than other inserts I've tested.
True, the insert would likely do more to support the tire with a smaller tire width, but 2.4" is becoming a common size even for XC racing. Also, I did this test after the insert was installed for three months, so perhaps if it was newer it would perform better. But if you're reading this review and considering buying one, you're probably hoping it will last far longer than that.
The bottom line is that the Air Liner Light no doubt makes it easier to finish a lap with a puncture when compared to no insert at all, and it probably makes those punctures less likely in the first place. But don't expect it to support the tire almost like it's inflated; you're still going to have to nurse it back to the pits. After all, this is 50 grams of foam we're talking about.
Ride impressions
Generally, the lighter the insert, the less of an effect it has on ride feel and the Air-Liner Light doesn't buck that trend. In the rear, it's barely perceptible, although there is a slightly more muted feel - like someone's added more compression damping. In the front, it's more noticeable - there's less of a jarring clang when you hit something really hard, and sometimes the tire feels more damped for a given pressure, but if you didn't know it was there it would be hard to tell the difference. While some inserts can actually make the tire feel harsher if they're too dense and take up too much of the tire's volume, the Air Liiner has no such issues.
In this screenshot from Vittoria, you can see how the force taken to compress the tire is much the same with or without the insert, until the last part of the tire's "travel", where the force required with the insert (red lines) ramps up dramatically. It's like adding a volume spacer or bottom-out-bumper to your suspension.
How effective is it at preventing punctures? That's very hard to assess without some sort of lab equipment, but generally, less weight results in less protection. I haven't punctured so far with the insert in a Maxxis DHR2 EXO casing tire, but nor would I necessarily have expected to.
Pushing an under-inflated tire against a square curbstone, you can feel the added resistance with the insert installed. Even with no air in the tire, there is a subtle but progressive ramp-up of force as the rim gets closer to the curb, so there is certainly a benefit if a subtler one than heavier inserts.
After three months on my bike, they show no visible signs of wear and haven't started soaking up sealant, so durability seems impressive.
 | With a real-world weight of just 50 g, I expected these inserts to either make no difference to the feel of the tire or to fall apart after a few rides. But they do a good job of muting trail feedback without adding harshness, and after three months in my tires, they look and feel like new. How much they reduce the chances of puncturing is hard to assess, but it's safe to assume they will reduce the risk somewhat. Vittoria's claim that they make it possible to keep riding after a puncture should be taken with a pinch of salt, as mine didn't seem to support the tire significantly more than other inserts after releasing the air. But in the event of a puncture, it's certainly going to be easier to get to the finish line than with no insert. Besides, the low weight and relatively low price mean they're still a good choice for XC, trail and potentially even enduro riders who want some rim/tire protection and don't want the weight penalty of a heavier insert. |
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Anyone else have issues with inserts like this?
Back to orange seal endurance now.
Conti Revo Sealant and Stans do not seem to suffer as much.
Stans Race Sealant doesn't seem to dry out faster with inserts but as it dries out quite quickly anyway it is hard to determine if the insert (Tannus and Cushcore XC) made a difference.
Tannus Tubeless insert in a Michelin WILD Enduro Front (both wheels) with Conti Revo sealant seem to be good for at least four months. But I am only running inserts on the e-Sight now (due to massive extra weight and it being my only bike with alloy rims).
I find that the better (Conti or Michelin) 1140-1350 gram 'enduro/ trail' tyres handle perfectly well without an insert and the associated pfaff that comes with them.
Ride flat properties are nice for those riding from home. If you're out for a short blast and puncture, it may be more efficient to nurse the bike home than to spend your remaining trail time trying to fix the tire (end then ride home). I'm just curious how slowly the insert deflates eventually. Both to know how quickly you need to be home as well as how long before a tire change you need to deflate the tire. I suppose it can be extra hard to remove the tire immediately after deflating it.
I do think the open cell foam could be nice. It will compress under pressure so that will provide more pressure against the tire bead keeping them from burping (which is one of my main reasons to use an insert) yet it will be soft when completely deflated so not particularly hard to install and remove a tire. They currently don't seem to make one for my wheelsize so I won't be testing it but I do think it always interesting to see different alternatives on the concept. I honestly believe that the current inserts differ more with respect to each other than some rear suspension designs. If there is a place for them, there is a place for different inserts too.
www.vitalmtb.com/features/tested-vittoria-air-liner-light-tire-inserts
Vital had great luck in their run flat test using this approach.
Any stretching with these lite ones?
27.5 availability for front tyres of "old" enduro bikes?
As the insert leaves the contact patch (rotates back up off the ground) it expands, drawing in sealant - and air (also the reason @seb-stott 's air retention experiment didn't work as planned). The lower the pressures, the greater the 'squeeze' each time that part of the insert spins around, the greater the effect.
As @BarneyStinson, @garrettstories and others have noted, this is less of a problem with closed-cell style inserts - at the cost of a faster degradation in the cell structure - and won't happen with plain plastic inserts - but they obviously don't offer side wall support.
So, will this insert stretch? For better and worse: yep.
They give a real protection to carbon rims also.
I
One month of what I would call light/regular use (170lb rider) and mine had multiple chunks cut off the sides, and a huge slice in the middle.
Pretty much worthless for their supposed task. I’m not sure what use case these would be good for.
50g insert instead of cca 100g of sealant, and in case of puncture I can still get back home without a need to carry a spare tube with me.
Would that work?
My theory is that because I’m running much lower pressures with lighter casings, they’re puncturing and then sealing a lot, and that’s what’s using up the sealant?
www.effettomariposa.eu/en-us/blogs/tech-news/tyre-inserts-why-is-your-sealant-drying-up-fast
Another huge thing is never add your sealant using the valve,it would difficult the sealant to reach is final destination and in some cases it would create a huge separate ecosystem with the tire insert and the rim. It is true you can add a little more of sealant and check it more regular.
I’ve considered trying them a couple of times then just thought my £ would be better spent elsewhere
Oh well horses for courses and all that.
It seems that less riders are using inserts in dh and Enduro, does anyone knows why?
Got to wonder how much benefit they’d give for trail riding though?
I'm concerned about these stretching though because the current Airliners have to be cut down every time you change your tyre.
Test Tubolight or PTN and get back to us, thanks.