OKO has expanded their bike tubeless sealant line with a new Magic Milk Hi-Fibre Race sealant, developed to excel at both super low (think DH or CX) and much higher (think road) pressures. This is where the performance of some sealants that worked great in early mountain bike applications tend to break down. And if like me, you haven’t tried or even heard of OKO Magic Milk, it might be worth taking a closer look…

OKO Magic Milk Hi-Fibre race spec tubeless sealant

OKO Magic Milk Hi-Fibre sealant high-pressure road, low-pressure DH CX MTB race spec tubeless tire tyre sealant

c. OKO

It seems like I find a new sealant maker almost as often as I set up a new wheelset tubeless. And it is surprisingly common for them to make claims of being magic. But how we missed OKO until now is a bit of a surprise.

Actually OKO is one of the original players in the tubeless sealant game, having first developed proven formulas in the UK back in the 1970s, long before bicycle tubeless was a thing. All OKO sealant is still made in the UK too.

What makes OKO’s Magic Milk sealant different?

And what sets OKO’s Magic Milk bicycle sealant apart besides their 40 year history, is the sealant formula does not need to be shaken. While most sealant formulas have little bits suspended in a liquid carrier, almost all require you to shake up the bottle before you add it to you tire. That’s not necessarily a bad thing as it is easy enough to do, and once it is in your tire it shakes up as the wheel spins. But when your bike (or the bottle) doesn’t move, the good hole-sealing bits sink down. OKO suggests this means that the sealant doesn’t keep as good of a protective layer on the inside of your tire, and that it may contribute to a decreased lifespan as well.

But there’s no need to shake Magic Milk or Magic Milk Hi-Fibre, both formulated so the latex-based fibrous bits that plug holes stay in solution, both in the bottle and in the tire (or as they say, the tyre).

The synthetic latex based sealants are amonia-free, and are designed for 6 months of full tubeless protection performance. Unlike many sealant options, Magic Milk does not ball up inside the tire, so you won’t create any Stanimal art to share on social media.

OKO even says their sealant works just as well inside butyl inner tubes, as it does tubeless tires. Although they have some other sealants that are said to work even better in tubes.

Magic Milk options & availability

OKO Magic Milk Hi-Fibre sealant high-pressure road, low-pressure DH CX MTB race spec tubeless tire tyre sealant

Now for 2019 OKO has doubled their cycling offerings with Magic Milk and Magic Milk Hi-Fibre. Both options also come now in five different sizes from the small 65ml bottle to carry with you when you ride, up to a mega 5L bottle for shop use.

Magic Milk claims to plus holes up to 6mm, while the new Magic Milk Hi-Fibre says it will seal holes 7mm across. The new high in fiber formula is faster acting with larger blue granules suspended in its milk, making it better suited to quickly seal high pressure road tubeless, or the larger cuts of low pressure setups for downhill or cyclocross racing. To us it’s not entirely clear why you might select the original formula vs. the newer Hi-Fibre, though?

Retail pricing looks the same for either variant: £5 for 65ml, £9 for 250ml, £13 for 500ml & £19 for 1L. No word on shop 5L pricing, but that one does include a sealant injector for team or shop use, as well.

Magic Milk is available through distributors in 30+ countries, and OKO looks like they are pushing to extend that even more. It also looks like you can get it from some online shops for around half those prices too.



  1. DooDoo on

    But did you test it? Claims are one thing, but how does it perform? Did you run over some small needles, then some nails, screws, glass???

  2. Chris Ring on

    Chris here from OKO. The 4-year old Australian test doesn’t reflect the current Magic Milk products, and we didn’t accept the findings back then… The new products have been tested and adopted by several leading race teams for 2019 onwards – in addition to Habitat MTB – Bart Brentjens’ CST MTB team, Ghost-Bikes Factory MTB team, Zappi Road team, KTM Alchemist Cyclocross/Marathon team and Gamux Downhill team. And now we are in the USA, distributed by KHS Bicycles and used by their factory MTB team.

  3. Peter on

    I had a puncture the other day about 3-4mm from something sharp assuming glass and the tyre lost all air and never sealed. Had to walk 3 miles. Topped up with extra 100mm and the tyre refuses to seal above 15psi. This is the hi fibre version. its way too tick and it doesn’t flow within the tyre. It may work with very tiny punctures and where the object causing the puncture remains in the tyre.

  4. Chris Ring on

    Sorry to hear that Peter. The product can be diluted if a specific issue is encountered (this doesn’t work with most other sealants) – try 20% water and mix well. Should solve your problem.

  5. Howard Cann on

    Hi, I’m using Oko magic milk in several MTB’s and results are mixed. I have had no problems including Alp trips but think I’ve been lucky.
    My two sons however have had small cuts in the top of the tyres (not side walls) that have not sealed, most annoyingly at BPW.
    I’m now experimenting and will regularly top up every two months before ditching the product.
    Last night in the workshop I deliberately punctured a 2.8 tyre (small hole) and it didn’t seal. I hadn’t topped up the milk so I added 15% water and injected it through the valve, no joy so had to push in a tyre bung which then held up to reasonable pressure, the Oko alone did not work.
    Note. I’ve been riding an mtb since 1986 so I’ve tried most available products.


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