Tyre Pressure Question.

[jonnb]

Having fitted winter tyres to my Superb Combi, 205/55/16, I checked the fuel filler cap ,and found that the pressure for this size tyre, was recommended at 2.4bar, and then the Skoda handbook added 0.2bar for winter tyres, making a total of 2.6bar, by my calculations, this should work out at 38psi.

However despite my figures, the tyre fitter recommended 35psi, as he said that 38 psi seemed far too high.

Does anyone here have similar tyres fitted, and if so, what pressure are you running yours on, as I think, that with the softer rubber in these tyres, 35psi makes the appear underinflated.

[Gizmo]

Yes I am also running 205/55/16 Nokian WRG2's fitted my my combi and they are inflated to 2.6bar as per the fuel cap recommendations

[casar]

Yes I am also running 205/55/16 Nokian WRG2's fitted my my combi and they are inflated to 2.6bar as per the fuel cap recommendations

+1

OK, my tyres are Continental WinterContact TS830, but everything else is the same.

Anyway, I would like to know *why* winter tyres should have 0.2 bar higher pressure?

Aleš

[Tankdave]

To help keep the tyres footprint as narrow as possible?????

[jonnb]

It might be due to the softer compound in the tyres, as when they were inflated to 35psi by the tyre fitter, they looked soft, When I adjusted the pressure to 38psi, they seem to sit much better, however my question is still, are my calculations right, does 2.6bar = 38psi ? or is it another psi figure.

[Superbjoser]

Yes I am also running 205/55/16 Nokian WRG2's fitted my my combi and they are inflated to 2.6bar as per the fuel cap recommendations

+1

On my Goodyear UltraGrip ICE+ 205/55/16.

/Superbjoser

[AnotherGareth]

does 2.6bar = 38psi ?

Close enough. Actually, just very slightly under 38 psi but much closer to 38 than to 37.

[jonnb]

Close enough. Actually, just very slightly under 38 psi but much closer to 38 than to 37.

Thanks for that, , but it goes to show, don't trust tyrefitters 100% as they wouldn't go above 35 psi, and said they heard nothing about adding extra to winter tyres, above the recommended pressure for summer tyres.

[safari hunter]

OK, my tyres are Continental WinterContact TS830, but everything else is the same.

Anyway, I would like to know *why* winter tyres should have 0.2 bar higher pressure?

First of all the tire running pressure is not the same inflating pressure when "cold". After some miles the tire starts to warm up to an increased 0.3 - 0.4 bar in the summer and 0.2 - 0.3 bar in the winter from the initial inflating pressure. Please consider that in the summer the asphalt temperature is quite high up to 60 degrees, when in the winter is near to 0 degree on average. So the temperature transfer between the contact surfaces is higher in the summer and lower in the winter. This summer / winter correction is to optimize the tire response in terms of flexibility and comfort while maintaining the grip on the winter road surface.

I use the same Continental TS 830 205/55/16 on my 2010 Superb sedan and I'm happy with 2,5 bar. So far great behavior on snow and icy roads.