New tyres for autumn

Some time ago, the man from our next door told to my husband that I am full of testosterone every time we talk about tyres. It may be true because, due to my work, I pay more attention than the average middle-aged mother to the properties of the tyre that contacts the road surface and the way the tyre does it. I can even say that knowledge adds pain and that things learned at Nokian Tyres’s Product Development have made me realize that tyres do matter.

At the weekend, I was busy bending down and checking the condition of the tyres of both our cars, with the morning paper under my arm. The reason for bending down next to the tyres was not a surge of testosterone but mainly maternal love and charity and probably a highly developed instinct of self-preservation. I wanted to make sure that my family was driving with safe tyres in the autumn rains without endangering us or other people in traffic by uncontroled slithering.

The purpose of the visual inspection was to ensure that we drive ourselves and our children in cars that have tyres with enough tread surface left to resist the increased risk of aquaplaning caused by wet conditions in autumn and make sure that the car will stop safely when breaking on a wet surface. I also decided to check the tyre pressures at my next stop at the service station.

All Nokian tyres have a convenient driving safety indicator (DSI), that is, a line of numbers in the tread where you can check the remaining depth of the tread in millimetres. The numbers disappear one by one as the tyre wears. There is a figure of a water drop between numbers 3 and 4 to remind of the fact that the risk of aquaplaning increases when the depth of the main grooves is below 4 mm. The legal requirement is that the minimum depth of the main grooves in summer tyres is 1.6 mm, but my opinion is that you should stay at home in rain with this kind of worn out tyres because their grip in wet conditions is almost non-existent.

With Nokian tyres, the depth of the groove is easy to inspect by checking the highest number that remaining in the DSI. With other manufacturers’ tyres, the depth of the groove can be checked with a specific groove depth meter, a slide gauge, or a two-euro coin. The coin is a quick and easy way: place the coin vertically to the main groove and check if you can still see the silver edging. If the silver edging is not visible, depth of the groove is over 4 mm. And, respectively, the more silver you can see, the more you should consider replacing the tyres with new ones. Driving with old summer tyres in autumn conditions until they are totally worn out is a very common and, in a way, understandable habit but, actually, a really bad idea. It would be safer to replace old summer tyres with new ones in autumn and take all the advantage one can get from the safe tyres in lousy weather.

I may give good grades to myself for checking the groove depth but not necessarily for measuring the tyre pressure. I hate measuring tyre pressure, and I admit that I do it too rarely. When you once measure the tyre pressures in wet snow, you quickly learn that it is worth taking the measurement every now and then in good weather. If the tyre pressure is too low, controling the vehicle in extreme situations becomes difficult, steering may increasingly drag to either side, and the risk of tyre break increases. Tyre pressure affects not only safety but fuel consumption as well, which is lower when driving with tyres with the correct pressure than with those with low pressure.
The result of the inspection was that, in terms of groove depths and tyre pressures, both our cars were ready for the challenges of autumn. I hope that all other people who rely on their tyres on the road will do the same inspections and take the necessary measures as a result of their inspections. It does matter what kind of grooves and pressures you drive with.


  1. Achim Lohse says:

    I’m on my second set of Nokia WRG tires, and recently had a high-speed flat. When I went to the Canadian Nokia retailer’s website, I couldn’t find any formula for pro-rating a tire that can’t be repaired. I went to Kal-Tire LiveChat and asked there, and was refused that information, and referred to the local dealership. And have been unable to get the information there too. So today, I searched the Nokia website for the information, and found nothing, not even and e-mail contact address or online form for technical support.

    Not only the formula for calculating pro-rated replacement of tires, but even the technical specs for my tires, and the recommended tire pressure for my vehicle proved impossible to locate. The only tire pressure “information” I’ve found here – that the vehicle manufacturer’s inflation figures on the door plate are always correct is something I know for a certainty to be WRONG. I drive a 2004 VW Golf TDI with 15″ wheels, and VW’s instructions are to inflate the M+S front tires to 33psi, and the spare and rear M+S tires to 45psi, despite the fact that the stock tires, Goodyear Eagle 195/65R15, have a maximum inflation pressure of 44psi marked on the sidewall.

    I’m writing this here, because it’s the only means of contact with Nokia I’ve been able to find.

    If this is the level of support I can expect from Nokia, I’ll go back to buying my winter tires from Hankook.

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