Seals tyres to rims, and helps prevent punctures.Good stuff if you've made the leap to tubeless on your road bike.
Slime Pro Tubeless Sealant
8 10

Slime Pro Tubeless Sealant is designed to do just that: seal your tubeless tyres onto rims. It also helps prevent punctures. If you've taken the leap to tubeless on your road bike, this stuff is very good indeed.

While tubeless tyres are common in the mountain bike world (and virtually universal on cars and motorbikes), the technology still hasn't really caught on for roadies. The reasons are legion, and the pros and cons of tubeless were discussed at great length when we reviewed some Hutchinson Intensive tubeless tyres here on road.cc last year. In fact, the discussion continues:


Without going into that discussion again, for those that do use tubeless tyres, then Slimepro sealant is good stuff. It does two separate jobs - seals the tyre to the rim, and helps repair punctures – and it does them both very well. In layman's terms it works by turning from a liquid to a solid when pushed through a small hole, effectively plugging that hole and making it airtight.

(Note. We're talking tubeless tyres here, not tubular tyres, which are a totally different thing.)

We tested the Slimepro Tubeless Sealant on those same Hutchinson Intensives, fitted to some Fulcrum Racing 3 Two-way tubeless wheels, using the following technique: Fit one bead of the tyre onto the rim; tip in the recommended 45ml of sealant, spin the wheel once gently; fit the other bead as usual; pump up tyre. The Slimepro sealed the small gaps between the tyre bead and the rim, and a track pump was enough the inflate the tyre. There was no need for a CO2 canister or airline. So on the fitting aspect, as far as our test tyres and rims are concerned, this sealant works.

On the other aspect – puncture protection – this sealant also works. With the tyre pumped up to 80psi, we stuck in a drawing pin and then rode the bike around the streets for a few minutes. The pressure dropped to 60psi then pretty much stabilised. It was definitely possible to keep riding.

Next, we pulled out the pin, and spun the wheel in the bike (to distribute the sealant on the inside), then started riding again. The pressure dropped to 50psi then stabilised as the sealant squeezed through the pin-hole and solidified. Then we pumped up the tyre to 100psi and five hours later it had dropped by only about 10psi – part of which was caused by attaching the pump again to check the pressure. So on the puncture repair aspect, Slimepro Sealant also works.

Despite the name, and unlike other products from the same manufacturer, Slimepro Tubeless Sealant isn't actually that slimey. It's much more liquidy. And it's white, not the trademark green of most other Slime products. It does leave a milky residue on the edge of the tyre and rim after fitting, but this is easily wiped off.

The recommended retail price for a 16oz (473ml) bottle of Slimepro Tubeless Sealant is a penny under 20 quid, although you can find it discounted down to £15 or less at your local bike shop and the usual on-line stores. This compares against similar stuff from Eclipse and Stans (both about £15 for about 500ml) or Effetto (£25 for 100ml).


Seals tyres to rims, and helps prevent punctures.Good stuff if you've made the leap to tubeless on your road bike.

road.cc test report

Make and model: Slime Pro Tubeless Sealant

Size tested: 473ml

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?

This product is for sealing tubeless tyres to tubeless rims. It also helps prevent punctures in tubeless tyres. It is not the same as the sealant that goes inside inner tubes, either as an 'instant' repair or as a puncture prevention measure. The slime website highlights the following key features:

"Specifically designed for use with tubeless bicycle tires; Guaranteed to outperform the competition; Instantly seals punctures up to 1/8 inch (3mm); Lightweight; Compatible with UST and conversion systems; Non-corrosive & non-hazardous; Seals bead."

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

The Slime website also says: 'After extensively testing other tubeless sealant products and identifying key customer complaints, Slime gathered a team of racing professionals to create a superior tubeless sealant product. The result is Slimepro Tubeless Sealant, an advanced formula that outperforms the competition. Slimepro Tubeless Sealant instantly seals punctures up to 1/8 inch and weighs in at just 1g per mL. This formula also contains our rust and corrosion package, a trademarked secret of our world class automotive tire sealants, designed to protect your expensive wheels from corrosion. As an added bonus, we replaced the standard toxic creepy chemical smell, signature of many tubeless sealants, with a tropical scent reminiscent of vacation days and pina coladas!'

Rate the product for performance:

Performance is excellent. Slimepro Tubeless Sealant seals tubeless tyres onto rims and helps prevent punctures – exactly what it's supposed to do.

Rate the product for weight, if applicable:

According the Slime website, Slimepro Tubeless Sealant weighs just 1g per mL. For a road tyre, a recommended 45ml is required, this obviously adds 45g to your rotating weight.

(Only a pedant would point out that most watery liquids in fact weigh 1g per mL, so this sealant is hardly unique. But I'll do it anyway.)

Rate the product for value:

The price is on a par with similar products from other manufacturers, meaning value is fair, but not an absolute bargain.

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

The product performed exactly as it's supposed to: seals tubeless tyres onto rims and helps prevent punctures.

Tell us what you particularly liked about the product

Performance. And I suppose the smell isn't bad – although hardly a deal-sealer.

Did you enjoy using the product? yes

Would you consider buying the product? yes

Would you recommend the product to a friend? yes

Anything further to say about the product in conclusion?

This products does what it's supposed to do, and on that basis scores 9. However, the price, although fair, is not a bargain, so a point knocked off, giving an overall score of 8.

Overall rating: 8/10

About the tester

Age: 51  Height: 5ft 10 / 178cm  Weight: 11 stone / 70kg

I usually ride: an old Marin Alp, or an old steel classic  My best bike is: an old Giant Cadex (can you see a theme here?)

I've been riding for: Over 20 years  I ride: A few times a week  I would class myself as: Experienced

I regularly do the following types of riding: touring, club rides, sportives, general fitness riding,