For those of you that have the 19-inch Sport Wheels on your Vert, what tire pressures are you running?

 

On the street, for every day use, I run 40 in the summer and push it up to 42 in the winter on the crappy NJ roads!

 

Wouldn't running such a high PSI have the adverse affect that you're looking for? To protect the rims, I'd think you'd want to run a lower / softer PSI especially in the winter.

On a side note, all of the tire guys that I speak to insist that we should be running at the factory specs at all times regardless of season. Granted, it is always important to adjust the pressure accordingly seeing as the pressure changes so quickly with the temperature. Tracking the car is something different.

 

spect2k,

The factory recommended tire pressure is higher for the Convertible (39 PSI) than the coupe and sedan. I run about 40 PSI as well.

 

Yea, I am aware. But bschurr made the comment about increased psi during the winter when I'd think it should go the other way.

 

Seems to be the right way, especially if he is measuring/adding while parked in his garage. From tirerack.com:
"If you are fortunate enough to park in an attached or heated garage you will also "lose" pressure when you leave its warmth and venture into the real world outside. So add 1 psi of "cold" tire pressure to compensate for each 10 degree temperature difference."
You do understand that your air pressure increases as temps go up (driving) and go down with cooler temps right?

 

I do understand that air pressure increases as temps go up Captain Obvious (nice time for the name!) My point is that raising the psi would maintain a fairly stiff tire. I personally lower my PSI in the winter time. The way that I do that is set the same 34 psi in the winter that I set in the summer. In the summer, it probably goes up to around 40. In the winter, it probably only reaches 36-37. This provides a softer tire to better protect the wheel from road damage

 

Theoretically a softer tire wil have better traction right? More rolling resistance, but a little better grip. The extreme is the offroad guys who air almost all the way down. The relationship between temp and pressure is of course correct as well.

 

Interesting topic...

Fronts 40 psi and rears 39 psi, seems to work good in So.Calif. I would suggest to get your tires filled with nitrogen. Nitrogen filled tire pressure stays quite stable as there's no moisture in nitrogen filled tires.

 

I'm not aware of any advantages to raising the air pressure in cold conditions as I live in a warmer area. I am however, positive, that low air pressure in a tire is actually less protection for a wheel. The amount that you are lowering it is probably not too significant, but it's definitely not adding any protection...

 

Factory pressure is 39 for the 19" rims. A few extra PSI is used to compensate for the colder temps and add a bit (albeit practically insignificant) more protection against the perils of inevitable pot holes. My use of pressure is not related to traction. The Vert is RWD with an open rear end so driving in the snow doesn't happen - period. I have dedicated AWD vehicles for that purpose.

You can talk to as many tire guys as you want but ultimately, you must make real world decisions based on your personal experiences. If you have something positive to add to the OPs inquiry I am sure we would all be interested in seeing it but this is the wrong forum to poke, flame and instigate others. Thanks for your cooperation in making this a productive place to discuss G37 convertibles.
All the best!
-B

 

Clearly you haven't read my post. The only person flamming anyone here is you...

My feedback is based on my experiences and understanding of the topic. My comments were meant to be helpful and nothing more. Clearly you know much more than me and are able to post factual information here as opposed to our opinions. Isn't that the focus of the forum, to avoid opinions and only post facts?

By the way, congrats on all of the vehicles!

 

My 2 cents: I or my wife drive the vert in the winter. I have the OEM winter 19" installed.
We live in an area of snow, ice and cold temps, this is wisdom passed on from father to son:
If you want better traction in snow: The higher the pressure, the taller the tire, the less surface area is in contact with the snow, therefore you get better traction in snow because the weight of the car is distributed on less surface area.
OEM calls for 39 PSI, I fill them to 40. So far I've commuted all week in the worst snow/ice conditions we've had in a long time and the car is behaving beautifully. The "Slip" icon comes on during acceleration so I back off the gas slightly but the winter tires are really working well.

 

Get your tires filled with nitrogen at same pressure and you notice the difference. Won't have worry tire pressure variance with temp changes. I use 40 in fronts and 39 in rears.

 

Regular air is 80% nitrogen. The specific heat capicity ratio of nitrogen is 1.404, the specific heat capicity ratio of air is 1.400. That the ratio of the amount of energy required to raise the temperature of the gas one degree. There's really no difference in temperature fluctuations between pure nitrogen and air.

Race cars and planes use nitrogen in their tires not for temperature reasons but for safety reasons. In case of a fire you don't want a compressed flammable gas nearby. Since nitrogen is inert if there's a tire and the tire does burst it will not feed the fire as air would since air contains oxygen.