Vittoria is one of the world’s leading manufacturers of premium bicycle tires with over seven million tires produced annually. In 2014, Vittoria began producing premium cycling wheels. In 2018, Vittoria joined in on the tire insert market with Air-Liner MTB. The innovative cross-sectional profile and high-quality polymer of Air-Liner MTB helped Gregor Raggl to win the Austrian national XC championship. This undoubted success led Vittoria to expand the product line and move into the ever-growing world of gravel cycling.
Vittoria has added the Air-Liner Gravel to its tire insert line-up. Adding Air-Liner Gravel to your wheelset will enhance grip, protect the rim from impacts, and help prevent pinch flats. Using the foam insert displaces air within the tire and thus allows for lower air pressure, prevents burping or tire bead breaking, and helps absorbs vibrations for a smoother ride. Air-Liner will give you greater control, more durability, increased performance, and protection of both rim and tire.
Air-Liner Gravel takes gravel riding to a new level by enhancing the ride experience on your bike. Air-Liner Gravel paired with Vittoria Terreno Zero (Fig. 1, Fig. 2) will provide more confidence than ever before, be it riding either rough gravel roads or single-track trails. The Terreno Zero Tires being reviewed have Anthracite color sidewalls but also come in Black and Gumwall. Air-Liner Gravel is compatible with tubeless-ready tires only. The Terreno Zero tires are for hooked rims only.
Air-Liner Gravel Design
Air-Liner Gravel was engineered to have a unique design compared to that of the original MTB version. The gravel version is shaped like a wedge and is designed to help lock the tire bead into the rim (Fig. 3a & 3b). The large upper radius shape allows for plenty of air space above that liner to provide a natural ride feel. Air-Liner Gravel is designed to be cut to length and is compatible with any wheel diameter up to 700c (29 in.) wheels. The uncut length is approximately 2.18 m (86 in.).
Air-Liner Gravel is suitable for rims with an internal width of up to 25 mm (0.98 in.). The cross-sectional dimensions can be seen in Fig. 4, and has an area of 3.7 cm2 (0.57 in2). The Air-Liner is made from EVA foam and will not absorb tire sealant. Under normal riding conditions, the Air-Liners have been tested (by Vittoria) to last up 2,000 hours or up to one hour if the tires are completely flat.
5-Way Tubeless Valve Stem
Vittoria provides a tubeless valve stem with the kit. If you are to use a regular valve stem, the Air-Liner rests on top of the hole and would possibly block the passage of air into the tire. Vittoria has cleverly devised a solution. Vittoria has placed air-ports on the sides as well as the top of the valve base. The base is aluminum but is wrapped with rubber underneath (Fig. 5a & 5b).
Setup of Vittoria Air-Liner Gravel is relatively simple and takes approximately 15-20 minutes depending on tire installation experience. The installation has been likened to installing a tube in a tire. The required tools can be seen in Fig. 6. The tools are:
- Razor Knife
- Cutting Plier
- Tire Lever
- Tire Sealant and Sealant Injector
- Air Pump/Compressor
Before installing the Air-Liner, it needs to be stretched first. Doing this improves its hold on the rim, and more importantly, it reduces the settling in the first few rides. Also, make sure that the rim has been properly wrapped and sealed with rim tape before installation. The installation steps are as follows, steps 1-7 can be seen in Fig. 7 and step 9 and 12 can be seen in Fig. 8a & 8b:
- Install the provided 3- or 5-way valve stem included with Air-Liner Gravel onto the rim.
- Wrap the Air-Liner around the rim and mark the Air-Liner where it overlaps. Make sure to make the mark slightly before the overlap so that after it is cut and the two ends are joined, it will fit snugly to the rim.
- Cut the foam Air-Liner with a razor knife at the mark made in the previous step.
- (a-b) Using a drill, nail, screw, or screwdriver, make a hole 2 cm from the ends of the Air-Liner.
- Install the provided zip-tie into both holes and tighten it such that both ends are joined together. Insert the zip-tie starting from the top side of the Air-Liner.
- Trim the zip-tie.
- (a-b) Test Air-Liner on rim to make sure it fits snugly, then remove it.
- Install one side of the tire onto the rim.
- Insert the Air-Liner inside of the tire and onto the rim. Wetting the Air-Liner and the inside of the tire with soapy water will aid in the installation.
- Install the second tire bead onto the rim, using a tire installation tool if need be.
- Remove the valve core from the valve stem and inflate the tire with an air compressor, tubeless inflator pump, or a stand-alone charge chamber. Ensure that the tire bead “pops” into place.
- Insert latex sealant (without ammonia) into the tire 50-120 cc (1.7-4 fl oz) depending on the tire size. For this installation, I used 59 cc (2 fl oz) of tire sealant. Reinstall the valve core. Fill the tire up to the recommend max air pressure, then bounce the tire to ensure the sealant spreads around and seals the tire properly.
Fitting and cutting the Air-Liner is a simple process. As with most tubeless tires, getting the last part of the tire bead was a little difficult. Getting the second tire bead onto the rim was more difficult than the first. Since the Air-Liner fits snugly around the rim, it prevents the bead from sliding to the center of the rim, which makes it a little harder to install the tire. Also, I was having issues getting the tire bead to seat without using soapy water. Once using soapy water, the tire seated perfectly. The wheels used in this installation are Shimano Ultegra WH-6800 wheelset with an internal rim width of 20.8 mm (0.82 in.). Using a wider internal rim width would probably make the tire installation slightly easier.
Air-Liner Gravel does add weight to the wheel system, but I believe the benefits of using them are greater than the marginal increase in weight. The trimmed Air-Liner Gravel with the trimmed zip-tie adds 43.7 g or about 1.56 oz of weight. The added weight is rotational weight, but I found no issues or differences with acceleration. Table 1 lists the mass of all the products used in this review.
The Vittoria Terreno Zero Tires
The Vittoria Terreno Zero (700 x 38c under review) tires are designed for hard-packed gravel or paved surfaces (Fig. 9). The smooth center tread provides a fast-rolling tire with low rolling resistance, but for cornering and braking, the Terreno Zero has a side thread that provides a grippy bite. The Vittoria Terreno tires feature a fish-scale like hexagonal pattern (Fig. 9). The scales are shaped such that the front edge of the scale is lower than the previous scale, this provides smooth low-resistance forward motion.
The side tread really shines when turning. A slight lateral movement causes deformation to the scales and that is when it really starts to grip the surface. Thus, providing you traction when you need it most. The Terreno Zero tires contain Graphene 2.0 to provide more durability and puncture resistance. The tires are tubeless-ready, have sidewall protection in the casing, and are 120 TPI.
The Terreno Zeros come in both foldable and ridged tire beads and come in 650 x 47c and in 700 x 32c, 35c, 38c sizes.
First Ride Thoughts
Right away you will notice that all the little bumps are deadened. The EVA foam does a really good job of taking up the vibrations and really smoothing out the ride. There is no noticeable increase in effort required because of the additional weight from the foam and there is no lag in acceleration. The Air-Liner really makes the ride quite a bit more comfortable.
The Terreno Zero tires feel fast on the road and on the hardpacked gravely surfaces. When making relatively fast turns on the road, the side tread gives quite a bit of confidence, and at no time did I feel the tires sliding out. I made a few turns through some loose sandy sections on the road and the tires managed well. They also performed well on my local rail-trail that is hardpacked with a fine loose granular surface. The minimum pressure for the Terreno Zero tires is 45 psi, but I ran 40 psi the first time with the tire insert installed. That pressure felt a little too hard and with the tire insert, you can run less air pressure without worrying about burping the tires. In subsequent rides, I dropped the air pressure to about 35-37 psi.
Long Term Thoughts
This setup with the Terreno Zero tires paired with the Air-Liner Gravel is a setup that gives a lot of confidence. Since using this combination, I haven’t had any pinch flats or air loss from burping the tires. Poorly patched asphalt roads and unpaved washboard gravel roads are not as jarring, and you have greater stability riding on these surfaces.
Air-Liner Gravel tire inserts really shine when it comes to poorly paved surfaces and chunky gravel roads. The ability to run at a lower air pressure will greatly increase your ability to manage these sections. Also, Air-Liners are great when riding rooty single track trails and technical sections are a bit easier when riding with lower air pressure.
The Terreno Zero tires really shine on hard-packed gravel and asphalt roads. These tires obviously are not designed for muddy, wet, or loose types of riding. Vittoria does offer other tire options for these types of conditions though. These tires are a great option when a less aggressive tread pattern is needed, especially when you do a lot of mixed-surface riding. The rubber compound is quite durable and has great puncture resistance.
Using Air-Liner Gravel makes complete sense, or should I say, not using Air-Liners doesn’t make sense. The added protection it provides to expensive carbon rims, alone makes Air-Liners a worthy investment. The Air-Liner insert absorbs the forces from impacts, thus preventing damage from hitting potholes or from riding up curbs. Also, if you ever get a flat tire, you can continue to ride on for up to an hour. However, I think I would only ride a flat in emergency situations only.
Vittoria claims an increase in performance, though this claim is probably hard to measure. In any gravel event, there are so many variables that come into play with the outcome of performance. Tracing back a performance increase to the Air-Liners may be quite challenging. But, Air-Liners do reduce vibrations, which in turn can help reduce fatigue. With the Air-Liner installed, I do notice a smoother ride and fewer vibrations in the handlebars. After long rides, I feel slightly less tired or weak in my arms and shoulders. This could just be placebo, but in mentally and physically demanding situations, every little bit helps.
I do enjoy using Vittoria Air-Liner Gravel and I will continue to use them on my current and future setups. I do like the Terreno Zero tires, but I would prefer if wider options were available.
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Jason Lopez of Jaylo Cycling is a Civil Engineer in training and is working on his Ph.D. in Wind Engineering. He is an avid cyclist and has over 10 years of combined experience between riding, training, and racing. His primary focus is road cycling, but he loves gravel, MTB, and touring.