Name: Silca Ultimate Tubeless Sealant v2
Brand: Silca

Ultimate Sealant has been two-and-a-half years in the making and achieves market leading sealing performance, with longevity and easy maintenance. It's capable of sealing holes up to 6+mm, while its hybrid natural and synthetic latex formula makes it long lasting and injectable, allowing clean top-up.

Silca's sealant has long made use of Fiberfoam® technology, which contains small strand carbon fibres, 400% stiffer than fibreglass, to plug punctures quickly and with minimal air loss.

The new formula ensures it will dry less rapidly and stay liquid for up to 6+ months, while adjustments to the carbon strand length have facilitated injectability, without any sacrifice of sealing power. The formula is also safe with CO2, not losing its effectiveness or coagulating during the inflation process.

The fibre dam created by the carbon fibre gives fast, effective sealing with minimal air loss, even in extreme conditions, such as temperatures down to -15°C, ensuring this sealant won't let you down.

Shop mechanics, meanwhile, will benefit from reduced labour time for installation and enhanced customer satisfaction, due to the sealant's ability to be injected through the valve core for easy replenishment.

Finally, Ultimate sealant is not only non-toxic and more environmentally friendly than competitors, but kind to your tyres, as it contains none of the ammonia that can break them down over time.

Fill guide

Sealant per tyre:

700c tyre:

x 28mm, 55ml
x 32mm, 65ml
x 40mm, 80ml
x 42mm, 85ml
x 45mm, 90ml
x 50mm, 100ml

29er tyre:

x 2.0″, 100ml
x 2.25″, 115ml
x 2.4″, 125ml
x 2.6″, 135ml

650b tyre:

x 47mm, 90ml
x 50mm, 95ml
26″ tyre:
x 2″, 95ml
x 2.3″, 110ml

Unbeatable sealing power in an injectable, long-lasting formula
Fibrefoam® technology forms interlocking “fibre dam” to seal holes up to 6+ mm
This is 25% larger than standard sealants
Hybrid Latex formula stays liquid for up to 6+ months
Natural and synthetic latex blend is durable, fast sealing and non-toxic
Injectable via valve for mess-free installation
Effective down to -15°C, for year-round reliability
Will not coagulate when exposed to CO2 during short term tyre inflation
Ammonia free
Contains latex, avoid inhalation and wear protective gloves/eye wear during application

Occasionally, without notice, manufacturers change product design and/or specifications.

Tubeless Sealant and Accessories Guide

Riding with tubeless tyres means that you’ll spend less time fixing flats and more time shredding the trails or lighting up the open road. In this tubeless guide we’ll look at all the things you need to get your wheels and tyres rolling without inner tubes.

Tubeless Sealant

Sealing all the little air gaps in your tyres, whether through a puncture or a less-than-perfect tyre/rim seal, tubeless sealant is an essential for every cyclist who wants to ride without tubes. There are a few different options to choose from, but they all work on the same principle: a liquid that solidifies when it leaks out of the tyre to seal gaps and punctures.

While simple latex-based liquids will work as sealants most brands sealants use special formulas and additives to improve longevity and sealing performance. Sealants with particles added are better at sealing larger holes so are ideally suited to mountain bike tyres. Lighter weight sealants are good for road bikes as puncture holes are generally smaller and easier to heal. Some sealants don’t work well with CO2, so check for compatibility if you plan on using a CO2 inflator to seat your tyre.

How much sealant should I use?

The amount of sealant you need to use will depend on the volume of the tyre. Brands will recommend specific amounts for their sealants which will be about 30 – 60ml for road bike tyres and 70 – 150ml for MTB tyres.

The table opposite shows typical sealant quantity recommendations to use as a starting point. If your tyres are a little porous some sealant may leak out. Don’t worry about this, it’s just the sealant doing its job, but you may need to top up with a little extra to be sure that there is enough left to seal any punctures.

Tyre size	Sealant quantity
27.5 x 2.0	75ml
27.5 x 2.4	110ml
29 x 2.0	90ml
29 x 2.4	130ml
700 x 25	30ml
700 x 32	50ml

Tubeless Sealant Accessories

Tubeless Rim Tape

If your wheel doesn’t have tubeless ready rim tape installed, then you will need to tape the rim with tubeless compatible tape. Tape is available in different widths and you’ll need a size that best matches the internal width of your rim.

applying tubeless rimn tape to an mtb wheel

Tubeless Valves

As there is no inner tube the valve attaches directly to the rim of a tubeless wheel. These are usually Presta valves. Make sure that you get ones that are long enough to easily go through the rim of your bike. Longer valves are available for deep section rims. The valve cores tend to block up with sealant after a while so they will need taking out and cleaning and/or replacing from time to time.

Tubeless Conversion Kits

Tubeless conversion kits contain sealant, tape and valves as well as fitting instructions, so these are the best option when converting your wheels for the first time. When buying a conversion kit make sure that you get one with the correct tape width and valve length to fit your wheel.

Sealant Injector

You can pour sealant into the tyre before you finish putting the tyre on, but many people prefer to inject the sealant through the valve. You can use a normal syringe, but specific injectors usually include a valve adaptor that makes the job easier. Some Tubeless Kits include an injector.

injecting sealant into a mountainbike tyre

Tubeless Tyre Repair Kits

While sealant will heal smaller punctures by itself a larger hole or tear in the tyre will need to be plugged or patched. Tubeless plug systems offer long lasting repairs and are very quick and easy to use even at the road or trail side. If you don’t want to have a small bit of the rubber bung showing through your tyre, then you will need to take the tyre off and patch it from the inside.

repairing a puncture in a tubeless mtb tyre

Tyre Inserts

Foam tyre inserts cushion the blows from rock strikes, especially when running low tyre pressures. They are a great way to protect your MTB tyre and rim when riding through rough terrain. Inserts can also help to keep the tyre on the rim more securely to avoid burping air when cornering.

Tubeless Inflators

When you fit a new tubeless tyre, it can sometimes be difficult to get the tyre seated properly on the rim. This is because a normal track pump doesn’t blow the air out quick enough to overcome the initial gaps between tyre and rim. Tubeless inflators allow you to blast a shot of air directly into the tyre to pop it onto the rim.

Tubeless inflators like the original Air Shot need to be pumped up with a separate track pump whereas others combine both track pump and inflator tank. See our range of tubeless inflators

How to Convert to Tubeless

While tubeless systems will save you time in the long run, they do take a little more care to set up.

See our Tubeless Tyre Conversion Guide for more.

2025 Gravel Bikes

Silca Ultimate Tubeless Sealant v2