dbdave

I own '14 and '16 base coupes, both purchased new. Both of these cars are non-Z51 with 18/19" tires that are the same Michelins.

The tire pressure label on the '14 says the correct pressure is 30psi. The label on the '16 says correct pressure is 35psi.

I've been running the '14 at the recommended 30psi since new and the tire wear is normal and the ride is good. The '16 doesn't ride any different with the pressure at 35psi and it's too soon to see any wear patterns.

Does anyone know when this was changed and for what reason?
Does the label on a '15 say 30 or 35 psi?
Did Michelin make changes to the tires between the years that would have made the change in pressure necessary?

I do know the '16 owner's manual says you can run the 18/19" tires at 30psi but warns of possible low pressure messages at that level. Now why would that all of a sudden be an issue? I also have read that the TPMS sensors may be different between the two years but I can't verify that.

rcooper

I have a '15 and it says 30 psi. I have looked at a couple of late build '15's at a dealer and saw the 35 psi on the label attached to the door. Not sure on the change date, nor why the increased psi, other than to squeak out another mile per gallon?
Guessing the program for the TPMS has been altered for the additional 5 psi.

owc6

Nothing changed physically, but the new cold pressure was implemented solely due to a desire to increase the MPG on paper, Tadge said so. Nutshell.

dbdave

Did he mention the increase was necessary for any reason other than meeting CAFE or avoiding the gas guzzler tax? Or, did they do it just because they could? The change doesn't seem necessary. The mpg is quite good without any increase in recommended pressure. I'm thinking there must be more to it.

stevebz06

If you've been following the news you might have noticed that Mitsubishi is in a bunch of trouble for raising their tire pressures during EPA testing to raise the mileage. The pressure from the Government is turning auto companies into criminal enterprises with mandated performance requirements.

If you like how the car feels at 30 psi then that's what I would use.

JerryU

I'm sure GM will do whatever it takes to raise the corporate mileage average 0.1 mpg! Can't blame them it's getting tougher.

Get ready for engine shut off when stopped (actually very unobtrusive in our 5X BMW SUV) and other power saving things to come.

Expect it won't be long when th Vette has 3 Liter dual turbo charged engines and Hybrid power boost systems like Formula 1 cars!

In fact F1 is getting 50% better gas mileage than a few years ago (now no refueling allowed) and are going just as fast! Just costs money!

Bettermost

Mine built in November of 14 says 30 but I did notice on the last oil change from the dealer they were filled to 35 now its making sense to me. Shouldnt they send everyone new inflation stickers if this is an across the board change?

Glen e

Its all done to increase the mpg for the EPA cycle, choose 30-35 or any setting between. There is nothing more to it.

Red08

The correct tire pressure for YOUR car should be posted on a sticker inside the drivers side door frame.

Curahee

alamo1974

Millerrock

They increase it so the stupid people stay out of the dealership!! They make us fill the tires at 40psi to keep the retards out of our dealership at the Audi/vw dealership, since those butterfly catchers can't even fill there own washer fluid, or they fill it with that green bug juice taking out the washer sensor and wonder why they have to pay for the repair! German crap, but there the only ones paying out there to fix there cars!!

AORoads

Could it be that the "recommended tire pressure" on the door for the Mitsu is X and Y pressure was used solely to improve their test scores? If the Stingray changed fr. 30 to 35 and both were on different model year's door, that's not illegal. It may not be for any other benefit besides MPG. Ride may get a little stiffer but that can be compensated for in other ways if it's too noticeable.

BEZ06

Just FYI - my 2016 Z06 (built Feb 19th this year) says 30 psi on the sticker.

.

sTz

Go with whatever the sticker cites on the inside of the driver's side door jam/frame. My '16 indicates 30 PSI.

Tire size shouldn't matter, only load, which is more important for trucks and hauling.

Yes, higher PSI equals better mileage. Lower PSI "generally" results in better traction and comfront... within a few pounds.

Too much pressure may result in excessive tire wear on the center tread. Too less... excessive wear on the outer tread.

Also, temperature affects PSI: Cold equals less/hot equals more. Accurate PSI readings should be obtained when tires are cool.

AND then there is nitrogen, but that's for another thread

Walt White Coupe

Run maximum of 30 psi cold if you want even tire wear. If you run the 18/19 setup at 35 psi cold, I will guarantee that you will run out the center of tires tread prematurely. If you don't care about even tire wear and want 0.1 mpg more then use 35.

SilverFish

Interesting thread. I have been running my 14 at 35 PSI since I bought it new. For some reason I thought that was what the sticker called for but this thread caused me to look again and it actually says 30. I think I assumed that since my Shelby GT500 called for 35 as well as my other cars then the Stngray would too. But the dealer has been putting it at 35 every oil change and now I have over 17,000 miles on her with no noticeable uneven tire wear so I see no reason to go to 30.

This same scenario occurred in reverse with the later C4s. I had a 89, 92, 94 and 96 and over those years GM lowered it steadily from 35 down to 30. Reason stated was that it made the ride less harsh with large diameter wheels (from 16" to the later 17").

Mobil 1

Z51 versus non Z51 tire pressures are different.
Whatever it says on the drivers door is correct.

jcp911s

There is no such thing as a "Correct" tire pressure.

It depends on the tire, compound, construction, driving conditions, and use.

Generally lower pressures improve ride, higher pressures improve handling and fuel economy...

Manufacturers have to balance a bunch of economic, legal, and marketing issues, so their recommendation is always a CYA compromise.

Are you racing or driving on a perfectly smooth highway? Is it winter or summer?

I found that on the track, 35PSI cold works for the factory Michelins on my Z51.

Use what works best for you.

AVETTE

Hello, I also have a Z51 and for me at the track once the tires hit 37 or 38 psi they seem to be "ballooning" and don't have as good a grip (stock MPSS) my tire pressures raise from 29 to 36 in one session on a hot day. Interested to find that you start at 35 what are they when you come off the track? Thanks for the info