Ninesomething Posted November 22, 2021 Report Share Posted November 22, 2021 Behind increasing the front tyre pressures for cars with 19" wheels? Got a bit bored last night and started reading the manual. 2.0bar for 18" wheels and 2.2 for 19s. Rears 2.5 either size. Quote Link to comment Share on other sites More sharing options...
edc Posted November 22, 2021 Report Share Posted November 22, 2021 Width of tyre changed? Quote Link to comment Share on other sites More sharing options...
Menoporsche Posted November 22, 2021 Report Share Posted November 22, 2021 Isn’t the sidewall lower? Thus increasing pressure gives a bit more protection over bumps? Quote Link to comment Share on other sites More sharing options...
½cwt Posted November 22, 2021 Report Share Posted November 22, 2021 3 hours ago, Menoporsche said: Isn’t the sidewall lower? Thus increasing pressure gives a bit more protection over bumps? A little bit of that and keeping a wider contact patch even across the tyre. Quote Link to comment Share on other sites More sharing options...
BBB Posted November 22, 2021 Report Share Posted November 22, 2021 The two options at the front of mine are 235/40/18 on an 8J wheel, or 235/35/19 on an 8.5J wheel. You can see from those figures that the overall tyre width is constant, but the 19s have a lower profile and sit on a slightly wider wheel. I presume that the higher pressure is needed to give extra support to the shorter side wall and the slightly wider section that sits on the wheel itself. Quote Link to comment Share on other sites More sharing options...
Greenman Posted November 22, 2021 Report Share Posted November 22, 2021 It does seem bizzare as a higher pressure gives a reduced contact patch. Smaller sidewall should be stiffer, extra pressure should not be needed. The advantage of wider tyres generally is it allows you to run lower pressures and increase the contact patch. Quote Link to comment Share on other sites More sharing options...
Ninesomething Posted November 22, 2021 Author Report Share Posted November 22, 2021 45 minutes ago, Greenman said: It does seem bizzare as a higher pressure gives a reduced contact patch. Smaller sidewall should be stiffer, extra pressure should not be needed. The advantage of wider tyres generally is it allows you to run lower pressures and increase the contact patch. This is exactly what I thought. I suppose Porsche know what they're doing. Quote Link to comment Share on other sites More sharing options...
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