The Schwalbe Doc Blue Professional tubeless sealant offers pretty decent protection against ending up with a fully flat tyre when out on the road, sealing against small intrusions quickly. You need to watch the tyre pressures if the hole is quite big, though.
The popularity of tubeless setups is increasing, with many riders making the switch from a tyre and inner tube combination, but to make this all work you need a decent sealant for when the worst does happen.
Doc Blue comes in at £7.99 for a 60ml bottle, which isn't cheap, but that'll sort both the front and rear when it comes to road tyres. (It's available in a bigger 500ml bottle too, for £20.99.)
Setting everything up is simple, with a valve core removal tool in the box. Unscrew the head from the valve and poke the top of the bottle into the hole to decant the sealant – job done.
Schwalbe says that the Doc Blue will remain a liquid for between two and seven months depending on conditions, and while I've only had it in the tyres for around five weeks it has been hot down here in the south west for quite a while – mid-20s for the majority of the time, with a few days nudging the 30s.
Taking the tyres off for an inspection before writing the review saw the consistency of the sealant as thin and runny as it was when it went in, so it isn't going to need replacing anytime soon. (Schwalbe says it's also reusable.) I'll keep an eye on that and let you know if I have any concerns.
I run my tyres at quite high pressures on the road, and the majority of foreign bodies trying to enter through the rubber or sidewalls get shrugged off. That's the main reason why I don't run any of my own bikes tubeless, and I wasn't exactly surprised to get through the test period without a single issue.
Taking things into my own hands, I stabbed the 28mm tyres with a drawing pin and the sealant dealt with the puncture quickly, losing only about 15psi from the original 90psi.
I left it for a few hours and pumped the tyre back up with no issues.
Making a larger hole – well, more of a slice with a scalpel blade (about 3mm long and the width of two scalpel blades) – saw a bit more of a skirmish from the Doc Blue to stem the flow of escaping air, but again it did the job, dropping to around 40psi.
With this larger tear, if I pumped the tyre up above 60psi the sealant would hold for a while before blowing out of the hole and having to reseal it again.
It was always at the 60psi range, so now that I know, I'd continue to ride without inflating the tyre above that and then fix it with a patch or plug at home before re-inflating to my desired pressure.
So, it works on the size of the holes you are likely to encounter on the road but it isn't the ultimate fix for everything. To be fair, Schwalbe does warn that it's 'Not effective on large defects (cuts/bursts)', so maybe I was being a little over optimistic.
When it comes to value, the Doc Blue does look a little pricey. The Muc-Off No Puncture Hassle sealant kit has an rrp of £9.99 for 140ml. Or you could go for Orange Seal Endurance sealant, £7.99 for a 4oz (116ml) bottle (or £14.99 for a 237ml bottle – enough for nearly eight tyres).
Up the bottle size and you get more Doc Blue for your money, 500ml for £20.99, but the same applies to the other brands, so it's still not the best value in comparison.
Overall, the Schwalbe does a decent job of keeping you rolling, but it's pricey against the opposition.
Seals the majority of punctures but it's quite an expensive way to do it
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road.cc test report
Make and model: Schwalbe Doc Blue Tubeless Sealant
Size tested: 60ml
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?
Schwalbe says, "Ideally suited for Tubeless conversions. Produced by Stan's NoTubes! It can also be used as a puncture protection preventative for bicycle tubes, tubular tires and standard Tubeless systems."
It does a decent enough job but there are cheaper alternatives.
Tell us some more about the technical aspects of the product?
Dose: 60 ml/tire (Race bike 30 ml). Effective ca. 2-7 Months. Thereafter dries to a rubber film. Can be renewed. Only suitable for tubes with a removable valve core. Not effective on large defects (cuts/bursts).
For this size of bottle it is quite expensive. Buy bigger and it works out better value.
Tell us how the product performed overall when used for its designed purpose
Seals the majority of holes without issue.
Tell us what you particularly liked about the product
Simple to use and looks like it'll last.
Tell us what you particularly disliked about the product
It can't cope with high pressures if the cut's quite big, but maybe that's asking too much of it.
Did you enjoy using the product? Yes
Would you consider buying the product? There are cheaper alternatives, so probably not.
Would you recommend the product to a friend? Yes, but I'd suggest shopping around.
Use this box to explain your overall score
For the majority of punctures you are likely to encounter on the road, Doc Blue should see you keep moving without issue, though there are cheaper ways to do it.
About the tester
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
With 20 years of road cycling and over 150,000 miles in his legs it's safe to say Stu is happiest when on the bike whatever the weather. Since writing his first review for road.cc back in 2009 he has also had a career in engineering including 3D-CAD design and product development, so has a real passion for all of the latest technology coming through in the industry but is also a sucker for a classic steel frame, skinny tyres, rim brakes and a damn good paintjob.
His fascination with gravel bikes is getting out of control too!