Page 47 - AMB Freelist

WORDS MIKE BLEWITT PHOTOS MIKE BLEWITT, NICK WAYGOOD
The Great AMB Tub
Tubeless tyre technology has come on in leaps and bounds since the UST system over two decades ago. Thanks to industry disrupters like Stan’s NoTubes, tubeless systems became more widely available, more adaptable, and more reliable. What started with sealant recipes, tape and tyre suggestions on forums is now normalised mountain bike products.
But how much thought do you put into your tubeless tyre sealant, or the system as a whole? An airtight seal is at the heart of a good tubeless system, so quality tubeless tape and valves are a must have, along with tyres that have a tubeless ready bead, rims to suit this bead and a casing suited to your riding style and trails. Beyond that, running the right tyre pressures will help avoid pinch flats and some cuts. Tyres have improved drastically in two decades, so the sealant really is only there to assist with sealing porous sidewalls, and to help repair a puncture.
Sealant works as the air rushes to a hole, with the particles in the liquid creating surface area for the latex or similar material to bond. This is why a larger hole is hard to seal, and a small repair can occur without you knowing. The liquid is typically reactive to an environment, so tubeless sealant doesn’t last forever, either in your tyres or in a bottle on your shelf.
TESTING SEALANTS AND NOT SYSTEMS
I set out to test 7 sealants by using the same tyre type on 7 wheels for a set period of time. Sealants were added to 29x2.4” Pirelli Scorpion LITE Hard conditions tyres as per the manufacturer’s recommendations. And then 36 days later after riding, hanging in a hot shed and general mountain bike use, the sealants were tested for the puncture repair performance. There were no punctures in the test period, kudos to Pirelli on their ProWall casing for that.
TEST PROCEDURE
Each tyre was inflated to 22psi, and then stabbed with a 3mm sharp tool near a transition edge block. They were ridden on a mixed surface of road, grass and dirt with a timer on. A time was recorded for when the puncture was sealed, with no visible bubbling or audible air loss, and the pressure recorded.
The tyre was then inflated to 22psi again, without any more sealant, and a 6mm cut was put in near a transition block, but 180 degrees opposite the last puncture. They were ridden again, and timed to repair with the pressure noted. A Dynaplug kit was carried
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