Confused about tire pressure
12-04-2016, 09:47 AM
#1
Drifting
Thread Starter
Confused about tire pressure
I'm upgrading my base wheels to the Z51 sizes. I see that the recommended tire pressure for the z51 is 30/30. The recommended tire pressure for the base is 35/35. Why would a larger wheel/tire require less air?
12-04-2016, 09:55 AM
#2
Oddly the recommended tire pressure for the base was 30/30 in 2014. Some speculate it was increased to increase gas mileage.
The following users liked this post:
justplainjim (12-04-2016)
The following users liked this post:
justplainjim (12-04-2016)
12-04-2016, 11:09 AM
#4
Le Mans Master
Member Since: Sep 2012
Location: Hagerstown MD
Posts: 6,876
Received 1,738 Likes
on
1,174 Posts
St. Jude Donor '15-'16,'18
For street use anything between 30 and 35, cold, will work fine.
The following users liked this post:
justplainjim (12-04-2016)
The following users liked this post:
DWSx (07-20-2023)
12-04-2016, 12:06 PM
#7
Le Mans Master
Member Since: Sep 2012
Location: Hagerstown MD
Posts: 6,876
Received 1,738 Likes
on
1,174 Posts
St. Jude Donor '15-'16,'18
The following users liked this post:
CCA Corvette Parts (12-04-2016)
The following users liked this post:
Aurora Flyer (11-03-2023)
12-04-2016, 01:28 PM
#10
Administrator
Member Since: Mar 2001
Location: In a parallel universe. Currently own 2014 Stingray Coupe.
Posts: 342,890
Received 19,284 Likes
on
13,961 Posts
C7 of the Year - Modified Finalist 2021
MO Events Coordinator
St. Jude Co-Organizer
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18-'19-
'20-'21-'22-'23-'24
NCM Sinkhole Donor
CI 5, 8 & 11 Veteran
The following users liked this post:
justplainjim (12-04-2016)
12-04-2016, 01:34 PM
#11
Inflate to the 30#'s cold. The tires will heat up and you will see on the dash readout they will slowly move up to 33-34#'s of pressure after driving about 15 minutes.
..
..
Last edited by nmvettec7; 12-04-2016 at 01:34 PM.
The following 2 users liked this post by nmvettec7:
justplainjim (12-04-2016),
Rebel Yell (12-04-2016)
12-04-2016, 02:00 PM
#12
Le Mans Master
Member Since: Sep 2012
Location: Hagerstown MD
Posts: 6,876
Received 1,738 Likes
on
1,174 Posts
St. Jude Donor '15-'16,'18
I was running 35 psi when I first took delivery of my car but I saw psi readings as high as 40 in the summertime so I have reduced my cold psi to no higher than 32. I usually run 32 Front and 30 Rear.
The following users liked this post:
justplainjim (12-04-2016)
12-04-2016, 02:03 PM
#13
A larger tire always uses less air. My Pro Street car rear tires which are 14.3 inches wide only use about 15-18 psi.
A bigger tire will handle a bigger load so less air is used to compensate.
Imagine if you had a tiny tiny GO kart tire on your vette, at the same psi it would be squished with the weight of the car. The only thing you could do is add more air.... a lot more air just to unsquish it.
A bigger tire will handle a bigger load so less air is used to compensate.
Imagine if you had a tiny tiny GO kart tire on your vette, at the same psi it would be squished with the weight of the car. The only thing you could do is add more air.... a lot more air just to unsquish it.
Last edited by Mobil 1; 12-04-2016 at 02:04 PM.
The following users liked this post:
justplainjim (12-04-2016)
Good one! 
12-04-2016, 04:15 PM
#16
Tirepressure advice is to give the tire a deflection for the speed you use, that wont give to high temperature of any part of the rubber of tire.
The advice is cold pressure , and pressure rising by temperature rising of the air in the tire is included in the advice.
So trying to give lower cold pressure , so warm it will be the adviced , is the wrong way to go.
This deflection is related to the speed , for higher speed lesser deflection is allowed so the same heat is produced so rubber wont go over the same temperature.
The maximum load given on sidewall is calculated for the reference pressure, so for speed of 160km/99m/h it wont give to high temp of rubber, and tiremakers use a system to highen up the reference pressure for higher speed, to give lesser deflection, because more cycles a second the tires make.
I am able to calculate a save lower pressure if you can produce 100% accurate the real weights on tires in the situation, and give the maximum speed you wont go over for even a minute.
From tires I need maximum load or loadindex, kind of tire to determine the reference-pressure, and the speedcode of tire ( letter QRSTHVWY(Y)).
Reference pressure of Standard load tire in USA system is 35 psi ( coincidence your advice ? no!), but most Low Hight/Wight division tires are XL/reinforced/Extraload and have reference pressure of 41 psi in USA system.
Now 100% acuracy is never possible , not in the weights on tires , but also not the measurement of pressure, so its best to calculate with as much possible reserve. But to much reserve gives unacaptable comfort and gripp.
Trick is to find the right balance between comfort and gripp , and savety of the tires.
Greatings from a Dutch Pigheaded Selfdeclared Tirepressure-specialist
Peter
The advice is cold pressure , and pressure rising by temperature rising of the air in the tire is included in the advice.
So trying to give lower cold pressure , so warm it will be the adviced , is the wrong way to go.
This deflection is related to the speed , for higher speed lesser deflection is allowed so the same heat is produced so rubber wont go over the same temperature.
The maximum load given on sidewall is calculated for the reference pressure, so for speed of 160km/99m/h it wont give to high temp of rubber, and tiremakers use a system to highen up the reference pressure for higher speed, to give lesser deflection, because more cycles a second the tires make.
I am able to calculate a save lower pressure if you can produce 100% accurate the real weights on tires in the situation, and give the maximum speed you wont go over for even a minute.
From tires I need maximum load or loadindex, kind of tire to determine the reference-pressure, and the speedcode of tire ( letter QRSTHVWY(Y)).
Reference pressure of Standard load tire in USA system is 35 psi ( coincidence your advice ? no!), but most Low Hight/Wight division tires are XL/reinforced/Extraload and have reference pressure of 41 psi in USA system.
Now 100% acuracy is never possible , not in the weights on tires , but also not the measurement of pressure, so its best to calculate with as much possible reserve. But to much reserve gives unacaptable comfort and gripp.
Trick is to find the right balance between comfort and gripp , and savety of the tires.
Greatings from a Dutch Pigheaded Selfdeclared Tirepressure-specialist
Peter
12-04-2016, 04:41 PM
#17
Tirepressure advice is to give the tire a deflection for the speed you use, that wont give to high temperature of any part of the rubber of tire.
The advice is cold pressure , and pressure rising by temperature rising of the air in the tire is included in the advice.
So trying to give lower cold pressure , so warm it will be the adviced , is the wrong way to go.
This deflection is related to the speed , for higher speed lesser deflection is allowed so the same heat is produced so rubber wont go over the same temperature.
The maximum load given on sidewall is calculated for the reference pressure, so for speed of 160km/99m/h it wont give to high temp of rubber, and tiremakers use a system to highen up the reference pressure for higher speed, to give lesser deflection, because more cycles a second the tires make.
I am able to calculate a save lower pressure if you can produce 100% accurate the real weights on tires in the situation, and give the maximum speed you wont go over for even a minute.
From tires I need maximum load or loadindex, kind of tire to determine the reference-pressure, and the speedcode of tire ( letter QRSTHVWY(Y)).
Reference pressure of Standard load tire in USA system is 35 psi ( coincidence your advice ? no!), but most Low Hight/Wight division tires are XL/reinforced/Extraload and have reference pressure of 41 psi in USA system.
Now 100% acuracy is never possible , not in the weights on tires , but also not the measurement of pressure, so its best to calculate with as much possible reserve. But to much reserve gives unacaptable comfort and gripp.
Trick is to find the right balance between comfort and gripp , and savety of the tires.
Greatings from a Dutch Pigheaded Selfdeclared Tirepressure-specialist
Peter
The advice is cold pressure , and pressure rising by temperature rising of the air in the tire is included in the advice.
So trying to give lower cold pressure , so warm it will be the adviced , is the wrong way to go.
This deflection is related to the speed , for higher speed lesser deflection is allowed so the same heat is produced so rubber wont go over the same temperature.
The maximum load given on sidewall is calculated for the reference pressure, so for speed of 160km/99m/h it wont give to high temp of rubber, and tiremakers use a system to highen up the reference pressure for higher speed, to give lesser deflection, because more cycles a second the tires make.
I am able to calculate a save lower pressure if you can produce 100% accurate the real weights on tires in the situation, and give the maximum speed you wont go over for even a minute.
From tires I need maximum load or loadindex, kind of tire to determine the reference-pressure, and the speedcode of tire ( letter QRSTHVWY(Y)).
Reference pressure of Standard load tire in USA system is 35 psi ( coincidence your advice ? no!), but most Low Hight/Wight division tires are XL/reinforced/Extraload and have reference pressure of 41 psi in USA system.
Now 100% acuracy is never possible , not in the weights on tires , but also not the measurement of pressure, so its best to calculate with as much possible reserve. But to much reserve gives unacaptable comfort and gripp.
Trick is to find the right balance between comfort and gripp , and savety of the tires.
Greatings from a Dutch Pigheaded Selfdeclared Tirepressure-specialist
Peter
You do not have to be a rocket scientist to put air in a tire and define the air pressure with a gauge. A 5 year kid can do it.
The recommendation of all auto manufacturers on the inside of the driver's door label is to check the pressure and inflate to the numbers on the door sticker when COLD. The GM C7 owners manual states the same.
Nothing more.
..
The following users liked this post:
owc6 (12-04-2016)
12-04-2016, 05:35 PM
#19
Team Owner
12-04-2016, 07:19 PM
#20
Melting Slicks
Where did you get the 35/35 value? Is this stated on your door sticker?