Cold weather = low tire pressure

ls2kev · 10-20-2009, 12:32 PM

Okay, so it's a known fact that when it's cold, molecules move more slowly, decreasing friction and heat, decreasing the pressure... blah blah blah.

So now that it's cold, obviously my tire pressure light comes on in the mornings. Should I just ignore this or fill up the tire with a little bit more air since (naturally) the pressure will be lower than it was during the spring/summer.

I just feel so weird when driving it and it tells me the pressure is too low.
By the time the day has warmed up a bit due to the sun, the pressure warning is (obviously) gone.

And since I'm garaging my car for the winter, what should be done about air in the tire? Check it every so often and refill as needed or just leave it be?

Thanks in advance.

GOLD72 · 10-20-2009, 12:55 PM

Rough rule of thumb is 1 psi air pressure drop in a tire for every 10degF drop in ambient temperature. I suspect that you need to add air to achieve 30 psi in the morning when cold. Even if your tires were not losing air pressure over time due normal leakage, tire pressure would still drop as we transition from summer to winter season.

GOLD72 · 10-20-2009, 12:59 PM

Quote:

Originally Posted by ls2kev

...............
And since I'm garaging my car for the winter, what should be done about air in the tire? Check it every so often and refill as needed or just leave it be?

Thanks in advance.

Some have suggested putting in extra air for winter storage (35-40 psi???) to help minimize or avoid flat spots on the tires. I wouldn't know as my vettes are year-round DDs.

ls2kev · 10-20-2009, 01:22 PM

Quote:

Originally Posted by GOLD72

Some have suggested putting in extra air for winter storage (35-40 psi???) to help minimize or avoid flat spots on the tires. I wouldn't know as my vettes are year-round DDs.

I look forward to the day I can say I have vetteS as DDs

Thanks for the info.

jpee · 10-20-2009, 01:53 PM

I live in NY and in the summer the temp can go to 95 + sometimes, and in the winter it can go to 10-15 deg..

I prefer my tires to be at 34-37 after they are warm (driving for 1/2 hr... So when COLD my DIC reads app32-33 lb... but now in cooler weather its reading 27 cold, and outside temp is 45-50 deg...

I just added air so my tires read 32 lb COLD on a 40 deg day... so even in very cold weather they will only drop to 29-30 when cold!

ls2kev · 10-20-2009, 01:56 PM

Quote:

Originally Posted by jpee

I live in NY and in the summer the temp can go to 95 + sometimes, and in the winter it can go to 10-15 deg..

I prefer my tires to be at 34-37 after they are warm (driving for 1/2 hr... So when COLD my DIC reads app32-33 lb... but now in cooler weather its reading 27 cold, and outside temp is 45-50 deg...

I just added air so my tires read 32 lb COLD on a 40 deg day... so even in very cold weather they will only drop to 29-30 when cold!

34-37 eh? My car b!tches at me if I put that much in. I try to keep it around 32.
2007 Base Coupe 3LT... don't know if there is a software difference in the models.

Dave S · 10-20-2009, 02:07 PM

The recommended tire pressure (30 lbs for the C6) is based upon the vehicle at ambient temperature. As pointed out, tire pressure will decrease as ambient temperature falls. Thus, tire pressure should be brought back up to 30 lbs (or 32 if you prefer) when the weather starts to get colder. Good idea also to check tire pressure with a reliable gauge rather then depending upon the readings on the DIC.

666vette · 10-20-2009, 02:15 PM

Quote:

Originally Posted by Dave S

The recommended tire pressure (30 lbs for the C6) is based upon the vehicle at ambient temperature. As pointed out, tire pressure will decrease as ambient temerature falls. Thus, tire pressure should be brought back up to 30 lbs (or 32 if you prefer) when the weather starts to get colder. Good idea also to check tire pressure with a reliable gauge rather then depending upon the readings on the DIC.

ls2kev · 10-20-2009, 04:07 PM

Quote:

Originally Posted by Dave S

The recommended tire pressure (30 lbs for the C6) is based upon the vehicle at ambient temperature. As pointed out, tire pressure will decrease as ambient temperature falls. Thus, tire pressure should be brought back up to 30 lbs (or 32 if you prefer) when the weather starts to get colder. Good idea also to check tire pressure with a reliable gauge rather then depending upon the readings on the DIC.

True. I use the pressure meter that came with my pressurized air pump.

Schoolteacher · 10-20-2009, 04:29 PM

I have run nitrogen in my other cars and it is supposed to stay constant, has anyone tried this or will it mess up the tire sensors?

c6 batmobile · 10-20-2009, 05:06 PM

Quote:

Originally Posted by Schoolteacher

I have run nitrogen in my other cars and it is supposed to stay constant, has anyone tried this or will it mess up the tire sensors?

Nope your safe. Nitorgen is actually a great source air for tires. A lot of dealers charge what I consider excessive for an inert gas but it is proven to not fluctuate as much as regular dry air which has a higher volume of oxygen. We use nitrogen to service our aircraft tires due to the fact they are at negative temps at altitude and then heat rapidly upon decent and landing.

Bottom line its good stuff. If you wanna pay the coin for it go ahead you wont have to adjust your tire pressure as often.

jadatis · 10-21-2009, 05:17 AM

I have been busy with calculating tire-pressure since 2007, with use of the formula the European tire- and car-manufacturers also use to determine the advice-pressures. Learned myself Excell to make spreadsheets for it.
The next spreadsheets could be of use in this topic.

http://cid-a526e0eee092e6dc.skydrive...0tyre-pressure
In this map always take the newest version , and there are examples placed. It is for recalculating advice-pressures for non OEM tires.

http://cid-a526e0eee092e6dc.skydrive...onwithtemp.xls
This spreadsheet is to see what the temperature does to the pressures.
You can see it is an older one, because of the simpler excel layout.
The calculating of the advice is a simpler one then the first spreadsheet.
It wat an experiment for races where the temperature in the tire gets higher then normal. The calculations are correct, and the idea was to get the same pressure warm for races then the warm pressure for normal use. Mind that the tire-surface is warmer ( about 60d C normal) then the air in the tire ( about 45 d C normal, races about 90d C).

To answer your question. Lower pressure when it is cold outside gives more energy- production ,so the tires heat up quicker. The lower pressure at the colder outside temperature normalizes the loss of energy production when it is cold outside. You could calculate your own pressures and let the light be adjusted for normal use. Then you have to be ware of highening up the pressure when heavy loaded, that will be your responcibility.

So use your advice pressures and asume they are for 20degrees Celcius ( Fahrenheit ???) Then use the spreadsheet to see what the pressure has to be at 5 degrees Celcius for instance.
Then fill them at that pressure, so lower. Always fill cold, so before the ride and not after. Your own pump with manometer would be handy then. can also be one for race-bikes, they also work with high pressures, and you dont have to fill much.

When you garage your car you may put the pressure up to the maximum of the tires, to prevent square tires. Then there is a less flatter piece on the ground. dont forget to lower the pressure to the normal advice when you go using the car again. better would be to put them on blocks so the tires get of the ground.

I live in Holland so excuse me for mis-spellings
Hope this will be of any help.
Greatings
Peter

nwc6 · 10-21-2009, 11:57 AM

Quote:

Originally Posted by ls2kev

Okay, so it's a known fact that when it's cold, molecules move more slowly, decreasing friction and heat, decreasing the pressure... blah blah blah.

So now that it's cold, obviously my tire pressure light comes on in the mornings. Should I just ignore this or fill up the tire with a little bit more air since (naturally) the pressure will be lower than it was during the spring/summer.

I just feel so weird when driving it and it tells me the pressure is too low.
By the time the day has warmed up a bit due to the sun, the pressure warning is (obviously) gone.

And since I'm garaging my car for the winter, what should be done about air in the tire? Check it every so often and refill as needed or just leave it be?

Thanks in advance.

I put 40-45lbs of air in the tires during winter storage. Helps prevent flat spots. I also park all four on carpet remnant squares. I run 30psi COLD tire pressure in summer, 32 in spring and fall, and usually end up with 34-35 HOT tire pressure..