Peaty’s tubeless sealant £29.99 (1l bottle)

Peaty’s sealant is ammonia free, so smells better than some formulas and should be less corrosive too, and the blue sealing particles are biodegradable (made from dyed tree bark). The first batch we tested was super-thick and gave mixed results in testing. We consistently had problems with even new tyres going flat overnight, until we swapped to a thinner competitor. Fortunately, Peaty’s made a running change. The new stuff is thinner (but not as runny as Stan’s) and uses a different type of latex. We’ve had no more issues with slow leaking, but in our standard test – using 100ml of sealant in a 27.5x2.3in tyre, inflating to 30psi, shaking and spinning the wheel, then stabbing the tyre and spinning it until it seals – it was slower to seal holes than Stan’s or Effetto Caffélatex, especially if the holes were in the sidewall. Using more sealant helped, but Peaty’s is already pricier by volume. Seb www.greenoversports.com