I'm sure your post will have the Porsche engineers reevaluating the recommmended pressures.I’ve done some searching and can’t find any defense for the higher rear pressures, so I’ll use conventional logic for performance driving and invert these pressures. We don’t need more understeer in cornering a front engine vehicle. Please prove me wrong....
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Yes my reply was a bit flippant. But the OP's question does raise an interesting point. Everyone knows that manufacturers build in a large margin of safety into their vehicles, and that understeer is easier for most consumers to manage than oversteer. Therefore, the mfg recommended tire pressures may favour understeer for liability reasons. So there's a possibility that a different pressure spec might be better for high performance driving by a skilled driver. And I guess that is the thought behind the OP's question.Now that's funny! A little sarcastic, but funny.
The side walls of the front and rear tyres are the same height, well almost the same 1.25 mm difference. For20” wheels front sidewall 119.25mm rear 118.00 mmMy 2cents. Everything else being equal.
A 40 aspect ratio sidewall will need a higher pressure than a tire with a 45 aspect ratio sidewall. The lower ratio tire sidewall cannot flex as much as the higher ratio sidewall, therefore it needs a higher tire pressure when compared to the higher aspect ratio tire.
Thanks iconoclast - this OP seems to support my thoughts and has some relevant background. I’m just surprised to think that Porsche would exacerbate the understeer with even more pressure in the rear, being a driver’s brand inspired by racing.
You been sold on advertising? Its a SUV meant to haul things and people. Despite "advertising" about 911 DNA, its not remotely resembling a sports car. It IS meant for softroading, snow, bad weather, and hauling. Porsche is Very Very good at marketing.Thanks iconoclast - this OP seems to support my thoughts and has some relevant background. I’m just surprised to think that Porsche would exacerbate the understeer with even more pressure in the rear, being a driver’s brand inspired by racing.
grim,You been sold on advertising? Its a SUV meant to haul things and people. Despite "advertising" about 911 DNA, its not remotely resembling a sports car. It IS meant for softroading, snow, bad weather, and hauling. Porsche is Very Very good at marketing.
The Quora article is talking about non-staggered setups. Since the Macan is staggered, the rest the article likely has no relevance.
Cargo is an issue but maybe not the entire issue.
@Caymancouver is more on target. I'm amazed at all the internet experts who know more about these cars than the people that build them. I never heard it before on tire pressures but its common on break-in and oil changes. People who believe the know better? Thats so interesting.
The GTS and PP issue someone brought up. While the Macan doesn't have this, the 911 has another set of tire pressures, for driving over 100. I forget the exact number. Crank up the cold pressure for driving at high speed. My guess is they consider the GTS and PP as the "performance" cars and hence crank up the pressure. They probably don't expect many base, S, or Turbo drivers on the Auto bahn doing 140. But thats a just a guess.
Which brings us to "driver's brand" inspired by racing and inducing understeer. I'm not tying to be flippant here but maybe trying to explain history.
The oversteer problem is a MASSIVE problem. They didn't call 930s Widowmakers because it sounded "cool". Its because people died. Once traction breaks lose, most everyone wants to lift. That means you die, or the tail hits the wall. Its counterintuitive that with RWD, you don't want to lift. But if the car understeers, lifting does eventually correct it and you don't plow into that tree.
Its a SUV. Its bought by tens of thousands of everyday people hauling their kids, buying groceries, going to Home Depot, not wannabe race car drivers. Where is the liability. If there is some gravel on the road, snow, whatever, do you really want a car that's going to go into oversteer for a SUV?
You know many people who actually take their brand new car out in the snow and practice with it to see how it handles at the limit? Yet you want to induce oversteer? My guess is they have the lawyers there all over the liability issue. Wife taking the kids shopping, hits the gas, tires break traction, she oversteers, lifts, hit brakes, and does a spin right into a pole. Meanwhile, if she plowed, she might have recovered.
If the answer is for handling, then yes, understeer it is.