kpg1945

Took delivery of a 2013 Boxster S and the dealer inflated the PZeros to 33 front, 36 rear. The plaque in the door recommends 33 on all four. When I asked the service manager why he went against the factory recommendation, he mumbled some stuff that didn't make a whole lot of sense. Then, in official Porsche promotional material, there was a small photo showing the tire pressure monitoring screen. Lo and behold, 33 front, 36 rear. So, any advice on which to follow?

Byprodriver

Too high is better than too low & rears are at 36 now so as you drive if you would like a softer ride in the rear let out a pound or 2. You may want to add a pound or 2 to the fronts to decrease understeer or just stiffen the feel. Monitor tread wear & adjust if needed.

Macster

Service managers are nice people and some are quite knowledgeable but you should have spoken with a tech about the tire pressure.

I've always gone by the tire inflation numbers on the sticker in under the lid of the gas cap cover or I guess now it is on the door jam.

Now you have to be careful you are not using the tire inflation pressures for a max loaded car. This I gathered from speaking to a tech about the tire pressures for my Turbo. When I checked the tire pressures after getting the car back once I noted the tires were not inflated to the pressures on the sticker but a few psi less. When I asked the tech about this he explained the numbers on the sticker were for a fully loaded car -- in the case of the Turbo 4 150lb adults and their luggage (several hundred pounds IIRC) -- but for a less loaded car a few psi less were the right numbers.

Based on the car's ride with the lower inflation pressure the ride is less harsh and handling is still superb and tire wear life is quite good.

So, it could be the 33/33 is for a lightly loaded car while 33/36 is for a fully loaded car with two adults and their luggage.

But speak with a senior tech.

San Rensho

Boxters have a lot of understeer dialed into the suspension and one way to lessen it is to increase tire pressure in the front. I run equal tire pressures all around, 36 psi, and the car handles much better than with the recommended 29/36.

Macster

I've not found understeer to be an issue with my Boxster and how I drive it when tire pressures 29 front, 36 rear.

What I did encounter was a tire out of balance like vibration that was from running the front tires with too much pressure. My recollection is it was no where near 36psi, more on the order of just a few psi over the 29 psi.