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Silca Ultimate Tubeless Sealant Replenisher



Extends the life of Silca's impressive sealant, and makes it more cost effective
Prolongs Silca's expensive sealant
Easy to inject through the valve
Only worth buying if you’re using Silca Ultimate Sealant

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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Silca Ultimate Tubeless Sealant Replenisher is designed to prolong the life of the tubeless sealant of the same name, but it'll also work on its own to get you out of trouble. If you're using the Silca sealant then this Replenisher makes the initial cost more appealing as the months pass by. As a sealant on its own, though, there are better on the market for less money.

Having reviewed Silca's Ultimate Tubeless Sealant back in the summer, I've had it sloshing around in my tyres for around six months now, a period that happened to include some of the hottest temperatures seen in the UK.

Many sealants can start to dry out in those conditions, requiring a replacement. This Replenisher reduces the need for that, when using Silca's sealant.

> 9 things they don’t tell you about tubeless tyres

The key to Ultimate Tubeless Sealant, according to Silca, is that it can work at the high pressures found in road tyres thanks to a foaming latex that carries a blend of 6mm, 9mm and 12mm carbon fibre strands to block the holes.

In testing I found it be very impressive, sealing holes in tyres while the pressure was still high, above 80psi, meaning pumping up at the side of the road wasn't required.

> The 8 essentials to take with you when you use tubeless tyres

Over time the latex part of the sealant does dry out, but obviously the carbon strands don't, so this Replenisher is basically topping up that latex.

How to use

For the first addition Silca recommends a top-up of 1oz/30ml (in a road tyre up to 30mm wide) after three months; then 1.5oz/45ml after six months, and another 2oz/60ml after nine months, to extend the life of the sealant to 12 months.

If you're switched on you will note that a 4oz bottle isn't going to achieve that, coming up half an ounce shy. The Replenisher is available in a 32oz bottle, too, though.

Because of the liquid nature of the sealant, Silca says the Replenisher can be injected into the tyre through the valve once the core is removed. It's easy to do this if you have a syringe and a bit of tube lying around. Or you can do as I did and pop a bit of the tyre off the rim, add the right amount of sealant, and reseat the tyre.

I've tested the sealant again since adding a top-up and it still works in the same way as the original sealant did, sealing homemade cuts into the tyre at similar high pressures.


This 4oz/118ml bottle costs £14, which on its own is pricey. CST's tubeless sealant is £10.30 for 250ml, for instance, and will perform better than the Replenisher if used on its own.

It's difficult to gauge value against the majority of opposition, though, as the Silca has a very specific job of lengthening the life of its Ultimate Sealant, and by doing that it makes that pricey sealant less expensive.


If you have Silca sealant in your tyres and you want to continue to use it by extending its life then the Replenisher works well and is worth the investment to lower the price overall.


Extends the life of Silca's impressive sealant, and makes it more cost effective test report

Make and model: Silca Ultimate Tubeless Sealant Replenisher

Size tested: 118ml

Tell us what the product is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Silca says, "Use Ultimate Tubeless Sealant Replenisher to inject into your tires and keep your Ultimate Tubeless Sealant w/FiberFoam going for 12-18 months!"

It does what it says on the bottle.

Tell us some more about the technical aspects of the product?

Silca lists:

* Effective down to 0F/ -18C

* Compatible with sealant injectors

* Comes with rubber hose for easy injection

* When used every 90-120 days, can extend Ultimate Tubeless Sealant w/FIBERFOAM life to a year

* Use Replenisher every 90-120 days for best performance

* Made in the USA

Rate the product for quality of construction:
Rate the product for performance:
Rate the product for durability:
Rate the product for value:

Tell us how the product performed overall when used for its designed purpose

It keeps the Ultimate Sealant working.

Tell us what you particularly liked about the product

It extends the life of Silca's Ultimate Sealant.

Tell us what you particularly disliked about the product

Pricey as a basic sealant solution.

How does the price compare to that of similar products in the market, including ones recently tested on

It's pricier than many standalone sealants, although the Silca isn't designed to work on its own necessarily. It makes the Silca Ultimate Sealant better value for money in the long run.

Did you enjoy using the product? Yes

Would you consider buying the product? Yes, as I'm using Silca's Ultimate Sealant.

Would you recommend the product to a friend? Yes

Use this box to explain your overall score

Used on its own the Silca will seal small holes as it is just a latex compound. It's designed to work as part of Silca's sealant recipe, though, and by making that sealant work as well as it does from new it's a cost-effective solution, and very good.

Overall rating: 8/10

About the tester

Age: 44  Height: 180cm  Weight: 76kg

I usually ride: This month's test bike  My best bike is: B'Twin Ultra CF draped in the latest bling test components

I've been riding for: Over 20 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: time trialling, commuting, club rides, sportives, fixed/singlespeed,

As part of the tech team here at F-At Digital, senior product reviewer Stu spends the majority of his time writing in-depth reviews for, and ebiketips using the knowledge gained from testing over 1,500 pieces of kit (plus 100's of bikes) since starting out as a freelancer back in 2009. After first throwing his leg over a race bike back in 2000, Stu's ridden more than 170,000 miles on road, time-trial, track, and gravel bikes, and while he's put his racing days behind him, he still likes to smash the pedals rather than take things easy. With a background in design and engineering, he has an obsession with how things are developed and manufactured, has a borderline fetish for handbuilt metal frames and finds a rim braked road bike very aesthetically pleasing!

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OnYerBike | 1 year ago

Stu - Interesting that you liked this sealant when your colleague Matt over on very much did not (

Any comment? The general impression I get is that it's very hit-and-miss, as a result of both variability within the manufacturing leading to an inconsistent product, and also highly variable interactions with different tyres and/or rim tapes.

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