Air Pressures and Handling - 996 Carrera 4
Discussion
Chaps,
I checked the pressures on my Carrera 4's tyres a couple of days ago, they were all at around the 30psi mark.
I have the 18" Turbo alloys with the staggered rears at 265.
Under the hood the factory guide was something like 36psi for the fronts, and 44psi for the rears!
I pumped them up to the guidlines and now the handling feels a bit skittish in the wet, not something I could ever accuse the 4 of being before.
I've noticed fairly obvious understeer going into a few roundabouts a bit hot (wet tarmac) and also had to correct the rear a couple of times coming out of roundabouts (wet tarmac) no biggie to do, but never really had this before.
Should I just back off the pressures a little and take the worse fuel consumption but grippier handling. Or does running with a lower pressure not actually give you additional grip? I genuinely don't know.
For reference the tyres are P-Zero Rosso's all round.
Cheers
I checked the pressures on my Carrera 4's tyres a couple of days ago, they were all at around the 30psi mark.
I have the 18" Turbo alloys with the staggered rears at 265.
Under the hood the factory guide was something like 36psi for the fronts, and 44psi for the rears!
I pumped them up to the guidlines and now the handling feels a bit skittish in the wet, not something I could ever accuse the 4 of being before.
I've noticed fairly obvious understeer going into a few roundabouts a bit hot (wet tarmac) and also had to correct the rear a couple of times coming out of roundabouts (wet tarmac) no biggie to do, but never really had this before.
Should I just back off the pressures a little and take the worse fuel consumption but grippier handling. Or does running with a lower pressure not actually give you additional grip? I genuinely don't know.
For reference the tyres are P-Zero Rosso's all round.
Cheers
The inflation pressures you found may be for a fully loaded car. My 03 Turbo has similar numbers and the techs tell me the pressures are for a fully loaded car. Consequently the car comes out of the service bay with lower f/r tire pressures. Lower by just several psi.
To run 30psi all around is I believe -- but have no reference to back this up -- way too low.
You might try 2psi lower than the 36/44 numbers and see how that feels. If you want drop the cold pressure by another 2psi to say 34/42 and see how that feels.
Whether you can go any lower I can't say. Not sure where you can find out how low you can go and still have the tires properly inflated.
To run 30psi all around is I believe -- but have no reference to back this up -- way too low.
You might try 2psi lower than the 36/44 numbers and see how that feels. If you want drop the cold pressure by another 2psi to say 34/42 and see how that feels.
Whether you can go any lower I can't say. Not sure where you can find out how low you can go and still have the tires properly inflated.
My 996 C2 on 18s has the same 36/44 recommendation and like you, I found the handling a bit skittish. I checked a few forum threads and found many people use lower pressures. I guess it's a case of trial and error to find what works best for you and your car but I've been using 32/36 for the last 2 years. Tyre wear is even across the tyre.
Since yours is 4wd and so presumably heavier at the back, you might be better off with 38 or even 40. Just a guess.
Since yours is 4wd and so presumably heavier at the back, you might be better off with 38 or even 40. Just a guess.
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