SAAC Forum

Off Topic Area => The Lounge => Topic started by: deathsled on March 17, 2018, 09:12:51 PM

Title: Good time to check tire pressure
Post by: deathsled on March 17, 2018, 09:12:51 PM
Checked my tire pressure on big red and all four were down a bit.  Pumped them up after the oil change and all is good.  Word to the wise to check and maintain tire pressures.

Richard E.
Title: Re: Good time to check tire pressure
Post by: shelbydoug on March 18, 2018, 08:04:31 AM
Yes. Tire pressure for me seems to disproportionately decrease with big cold temperature drops. There is an engineering chart around that shows something like a 1 psi drop for every 10 degree drop BUT personally I've seen tire pressures regularly drop to about 15 psi from about 32 when the temps suddenly drop from the 40's to the low teens.

Probably has more to do with the ability of the valve stem to hold pressure under those conditions rather then the compression of the air in the tires.

Just my observations. Scientists may disagree.
Title: Re: Good time to check tire pressure
Post by: Bigfoot on March 18, 2018, 08:33:16 AM
"Changing gears...."
Its always a struggle to figure out exactly the pressure you need on the track.
And of course as you push the car and the temps go up so does the psi.
Title: Re: Good time to check tire pressure
Post by: deathsled on March 18, 2018, 01:13:31 PM
I've never been out on the track as a driver.  But totally logical as air molecules heat they expand therefore change the reads.  I understand that nitrogen filled tires work better because nitrogen is less susceptible to expansion.   
Title: Re: Good time to check tire pressure
Post by: shelbydoug on March 18, 2018, 01:34:06 PM
Quote from: deathsled on March 18, 2018, 01:13:31 PM
I've never been out on the track as a driver.  But totally logical as air molecules heat they expand therefore change the reads.  I understand that nitrogen filled tires work better because nitrogen is less susceptible to expansion.

Yes.

I like helium better. When I go too fast it makes the scream a higher pitch.
Title: Re: Good time to check tire pressure
Post by: Alan on March 18, 2018, 02:55:21 PM
Helium held its pressure for me but traction got real sketchy.
Title: Re: Good time to check tire pressure
Post by: shelbydoug on March 18, 2018, 05:24:51 PM
You need to breath the helium.