[craig66]

Was doing some spirited driving this morning and took a right turn. Must have been some loose gravel/cement (Shitty NJ roads) and the rear slid out and then skipped twice before gaining a foot hold and traction. Shortly thereafter readings in my left rear tire when from 32 to 27.

I refilled my tire. looked for a nail which was not present and the remainder of the ride was without issue and tires stayed at 32.

I am assuming that the action of skipping and the wheels then catching traction again led to a distortion which released air momentarily but that at this time there is no damage to either the tire, wheel or axle. It was not dramatic but definately did feel the slide out.

Does this sound about right - Thanks

 

[Westcoaster]

Hmmm, right turn, skip and left tire pressure low, are you sure that the pressure wasn't already low in the left rear and that caused the skip?

 

[craig66]

I don't believe so. TPMS before leaving home stated all tires at their usual pressure

 

[Westcoaster]

I don't believe so. TPMS before leaving home stated all tires at their usual pressure

Interesting, it would have taken quite a push on the side of the tire to momentarily move it off the bead to allow the air to escape... I have always wondered if this was possible to do, I guess that it is!

 

[craig66]

Strange thing is that I was not going crazy. It was spirited but no that fast and strange that, that kind of force would have led to that but I do not see any other reason for the loss of pressure.

 

[DriveInHouston]

What size rims?

At least for my 2018 CS with 20" rims the recommended cold inflating pressure is 33 psi all around. This translates to 35-36 psi when the tires warm up and the spirits go up...

Is it, maybe, that 32 psi might be on the low side?

 

[Westcoaster]

What size rims?

At least for my 2018 CS with 20" rims the recommended cold inflating pressure is 33 psi all around. This translates to 35-36 psi when the tires warm up and the spirits go up...

Is it, maybe, that 32 psi might be on the low side?

Possibly Comfort pressure?, this setting for the TPMS indicates that with 20" wheels and tires 30 psi is the norm...

 

[craig66]

I have 19" Rims - sticker says 30 Front and 29 Rear. Is this not correct?

 

[Westcoaster]

I have 19" Rims - sticker says 30 Front and 29 Rear. Is this not correct?

Other way around front 29 psi rear 30 psi

 

[craig66]

Sorry my oops that what I meant. 30R and 29F. It seems though that people are running higher. I like comfort but am spirited (hence my issue this morning) and so should I be running higher than that?

 

[Westcoaster]

Sorry my oops that what I meant. 30R and 29F. It seems though that people are running higher. I like comfort but am spirited (hence my issue this morning) and so should I be running higher than that?

Unless I missed it in the manual, for 19" wheels there is no pressure suggested as a comfort setting, this is only for 20" wheels... so from the Porsche recommended pressures for 19" wheels you should be fine on the street. As you know the pressure specification is for 68F and it doesn't take long for the pressure to increase while driving, easily going up by 5 psi so unless it is recommended by a tire specialist or the manufacturer I would go by the book.

 

[MikesGTS]

Possibly Comfort pressure?, this setting for the TPMS indicates that with 20" wheels and tires 30 psi is the norm...

Agreed mine too, I run 30psi... only because I drive enough for the tyres to reach 32/33... which stops the under inflation effect on the tyres.

 

[sevencyclist]

I have had burping of mountain bike tires with loss of pressure suddenly on a turn when pressure was low. The sideway rolling pressure pushed the bead off the rim temporarily and air escaped. I can see how this can happen to outside rear tire with extreme force, but your initial normal pressure should have pushed the tire bead firm against the rim to prevent this from occurring. Not sure what happened there.

 

[craig66]

Update, after sitting at work for several hours I found that again the pressure had dropped. This time exhaustive review of the tire revealed a nail in the wheel. Not sure what happened this morning and maybe it was more a feature of the colder NJ morning together with a temperamental TPMS and that it was not as instantaneous as I thought. Not thrilled about the nail but at least have a better understanding of what happened.

I guess that wheel and tire insurance will be kicking in already.

Craig

 

[GregW]

It sounds to me like the nail initiated a pressure loss that precipitated the skip, or the nail was loose in the debris and the skipping 'nailed' your tyre.

Any significant loss should trigger the TPMS warning.