1985 Tire pressure?
Thread Starter
Race Director
Joined: Dec 2003
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From: Chicago Burbs, IL
St. Jude Donor '03 & '06
1985 Tire pressure?
I lost my owners manual and the door jamb says nothing about tire pressure. What is the GM recommended tire pressure on this car? 1985 Coupe 
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Both my IROC (with 16" wheels) and the Vette (with 17" wheels) recommend around 35psi.
Use more up front if you notice rounding of the edges from hard cornering and less in the rear if you need more hook.
Use more up front if you notice rounding of the edges from hard cornering and less in the rear if you need more hook.
Melting Slicks
Joined: Dec 2004
Posts: 2,954
Likes: 2
From: Obama=death for America
I'd go with 32-35, but if you're still unsure, look on your tire. It should have the recommended PSI. Some tires say 44, but I wouldn't go that high. I'd stick with 35.
Make sure you check the tires cold. If you check them hot, you will get an erroneously high reading.
Make sure you check the tires cold. If you check them hot, you will get an erroneously high reading.
Melting Slicks
Joined: Jan 2002
Posts: 2,531
Likes: 35
From: Lecanto Florida
Originally Posted by 85 500 horse
Make sure you check the tires cold. If you check them hot, you will get an erroneously high reading.
Hey, there's a good opportunity for a question. I keep mine at exactly 35psi (even have a little guage that talks to me and tells me when I reach the magic number
) and the tires get to around 39-41psi after a spirited run. Question: will there be a maximum number that's reached when the tires are hot? Can I count on that maximum number to check the tires if I don't feel like waiting overnight to get the coldest reading?Just thinking out loud, but have thought about checking the pressure maybe an hour after a run and remembered that everybody said, "check the pressure when cold".
Melting Slicks
Joined: Dec 2004
Posts: 2,954
Likes: 2
From: Obama=death for America
Originally Posted by CREWZIN
Hey, there's a good opportunity for a question. I keep mine at exactly 35psi (even have a little guage that talks to me and tells me when I reach the magic number ) and the tires get to around 39-41psi after a spirited run. Question: will there be a maximum number that's reached when the tires are hot? Can I count on that maximum number to check the tires if I don't feel like waiting overnight to get the coldest reading?
Just thinking out loud, but have thought about checking the pressure maybe an hour after a run and remembered that everybody said, "check the pressure when cold".
) and the tires get to around 39-41psi after a spirited run. Question: will there be a maximum number that's reached when the tires are hot? Can I count on that maximum number to check the tires if I don't feel like waiting overnight to get the coldest reading?Just thinking out loud, but have thought about checking the pressure maybe an hour after a run and remembered that everybody said, "check the pressure when cold".
And that's why they say to check your tires when they're cold. You get a false higher reading if you don't.
Melting Slicks
Joined: Jan 2002
Posts: 2,531
Likes: 35
From: Lecanto Florida
[QUOTE=85 500 horse] If the temperature dropped 20-30 degrees overnight, your tires will undoubtedly lose a few pounds.
QUOTE]
I guess there's not too much chance of that happening where we live. Thanks. Will continue to check them when cold.
QUOTE]
I guess there's not too much chance of that happening where we live. Thanks. Will continue to check them when cold.
Melting Slicks
Joined: Dec 2004
Posts: 2,954
Likes: 2
From: Obama=death for America
[QUOTE=CREWZIN]
That is true, but the exact opposite will occur when the weather is hot. In the dead of summer, our tires will expand and we'll need to let out a few pounds to compensate for the weather change. Running your tires that are off (up or down) by only 5 PSI will damage the tires (shorten their lifespan), decrease the handling and driveability of the car and decrease your mpg's.
If you get in the habit of checking your tire pressure once about every two weeks, you'll avoid potential problems. I check my tires 2-3 times per month. On two occasions, one tire was substantially lower than the other three. Believing I had a leak or a flat in progress, I took the car in to have the tire in question checked. Both times this occurred, there was a small nail in my tire and air was slowly leaking out. Before the tire was repaired and when I looked at it, I didn't notice anything was wrong. I only caught these flats in progress because of my habit of checking the tires. Just food for thought.
Originally Posted by 85 500 horse
If the temperature dropped 20-30 degrees overnight, your tires will undoubtedly lose a few pounds.
QUOTE]
I guess there's not too much chance of that happening where we live. Thanks. Will continue to check them when cold.
QUOTE]
I guess there's not too much chance of that happening where we live. Thanks. Will continue to check them when cold.
If you get in the habit of checking your tire pressure once about every two weeks, you'll avoid potential problems. I check my tires 2-3 times per month. On two occasions, one tire was substantially lower than the other three. Believing I had a leak or a flat in progress, I took the car in to have the tire in question checked. Both times this occurred, there was a small nail in my tire and air was slowly leaking out. Before the tire was repaired and when I looked at it, I didn't notice anything was wrong. I only caught these flats in progress because of my habit of checking the tires. Just food for thought.
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