Are winter tyres set at differing pressures to summer tyres listed in the owners handbook. Or are they inflated to the same pressures for the size whatever the type? Or is there a + or - adjustment needed for winters.
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I stick to the owners handbook recommended pressures for my Nokian WRG2's
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Try to set them to same pressure as the summer when tyres are cold. Don't however choose the coldest frostiest winter morning to set them as they will be a couple of psi out (+) on the milder winter days we normally get.
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Had this email from Ford parts manager Stuart Peck at Allen Parts (Ford Garage) on the subject. Bit long for here I'm afraid but worth sharing.
"Several vehicle manufacturer's owner's manuals recommend operating winter tyres several psi (typically 3-5) higher than their recommended pressures for summer and all-season tyres. While none of them actually provide the reason why, there are several scenarios that would support the practice.
First and foremost is that winter tyres feature more aggressive tread designs, softer tread compounds and are often moulded with deeper beginning tread depths than summer or all-season tires. While the combination of these design elements allows winter tyres to remain more pliable in sub-freezing temperatures to provide more traction in snow and on ice, it often results in tyres that have somewhat reduced responsiveness to driver input. The 3-5 psi higher recommended inflation pressures increase tyre stability and help offset the reduction in responsiveness.
Additionally ambient air temperatures in winter typically range 40- to 50-degrees Fahrenheit colder than typical summer temperatures for the same location. The lower ambient temperatures allow tyres to be more efficient at radiating heat and the tyres will run cooler, building up less hot tyre pressure. In this case, the 3-5 psi higher recommended inflation pressure increase helps offset the reduced hot tyre pressures resulting from less heat build-up.
And finally, all tyre pressures are intended to be measured cold, which means when the tyres are at the same temperature as the air outside. Unfortunately, unless you park your vehicle outside or in an unheated, detached garage, and measure its tyre pressures first thing on dark, cold mornings, the influence of attached garages or higher ambient air temperatures later in the day often means that drivers are actually measuring tyres that are not completely cold. In this case the 3-5 psi higher recommended inflation pressure increase helps offset the reduced tyre pressures associated with the conditions in which the tyre pressures are typically measured."
Last edited by: Mr. Ecs on Wed 5 Dec 12 at 16:49
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>> "Several vehicle manufacturer's owner's manuals recommend operating winter tyres several psi (typically 3-5) higher than
the .....................
>> reduced tyre pressures associated with the conditions in which the tyre pressures are typically measured."
>>
Cribbed from tirerack.com ..... www.tirerack.com/winter/tech/techpage.jsp?techid=168
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Nice of you to point out where it come from but you couldn't provide this answer to my query in the first place. I posted originally in November. All I wanted was an answer. Not a yah boo sucks I know where he got it from.What took you so long with the same info anyway?
Oh......yes......Mr. Snail!
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>> Oh......yes......Mr. Snail!
Merry Christmas and a prosperous New Year to you, Mr. Ecs. Peace on Earth and Good Will to all men.
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And to you old chap. Share and share alike.
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I live in a country were winter tyres are compulsory we fill them exactly the same as summer tyres no increase or decrease, In the event of a serious accident pressures are checked if possible any variation and its a few points against you.
Last edited by: Collos on Tue 11 Dec 12 at 21:19
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Ford Focus III - 10 1.8 Winter Tyre Pressures - Dog
