Washington DC -Â US-based consumer body Consumer Reports has recently looked into the use of nitrogen to inflate tyres and the practice of cutting extra sipes in tyres to allegedly improve grip. In both cases, the independent organisation reports some marginal improvements in performance, but concludes that the benefits are not worth the extra costs or the drawbacks.
For nitrogen, the organisation bought a nitrogen inflation system and used it for a year. "The results show nitrogen does reduce pressure loss over time, but the reduction is only a 1.3 psi (0.09 bar) difference from air-filled tyres. The average loss of air-filled tires was just 3.5 psi (0.24 bar) from the initial 30 psi (2 bar) pressure setting. Nitrogen-filled tyres lost an average of 2.2 psi (0.15 bar) from the initial 30 psi setting. More important, all tyres lost air pressure regardless of the inflation medium, so consumers should check their tyres' air pressure routinely. No evaluation was done to assess the aging claim." said CR.
The bottom line, said CR is that, "consumers can use nitrogen and might enjoy the slight improvement in air retention provided, but it's not a substitute for regular inflation checks."
Where siping is concerned, the organisation cut extra sipes in a couple of tyres and tested them for show traction and dry- and wet-braking. While braking on ice and snow showed modest improvements, braking on wet and dry roads was made worse.
CR concluded, "Besides costing $60 (€40) or so for a set of four, having your tyres siped potentially voids any tread-wear warranty. We don't think the modest gains are worth the extra costs.
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Blog from Consumer Reports (US) about Nitrogen in tyres
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