Tire pressure on an 09 GT

[KennedSR]

I generally keep my car's tires both winter and summer sets at about 32-33 PSI. My main question is that every time I take my car in for service to my Chevy dealership I find the pressure up around 40 PSI when I check my tires. I was always taught to follow the recommended pressure. I was not sure if my car dealer was onto something or if they just pump it up 40 because they believe their customers are idiots and never check their pressure. Thought I would ask and see if anyone else in the Vibe community had run into this issue before.

[beemerphile1]

They probably put the same pressure in every tire that comes through the shop. I've heard of people with trucks that require 70 psi finding a dealer put in 40.When I worked in a tire shop many years ago we inflated all auto tires to 32 psi. We didn't take time to check the recommendations for each vehicle.It won't cause a major problem providing you are below the maximum marked on the sidewall. Might cause a rough ride and over time will cause abnormal wear.

[KennedSR]

Thanks! It wasn't ever a real big problem it always just seemed odd to me but that makes a lot more sense.

[j42.snyder]

Maybe try checking it with a different gauge too just to see how it compares. I bought a cheaper dial type gauge once that read about 5PSI too high! I haven't trusted cheap gauges since.I was keeping my winter tires around 34, but I've found that the centers are worn about 1/32" more than the outsides now. Next year I'll probably drop the pressure a bit to the "recommended" 32 and see how they do. If my gas mileage slips noticeably, I'll bump them back up. 1/32" over 3 winters isn't much difference really I suppose. I'm sure that any 18" tires won't be cheap for yours though - so I'd probably try to keep it close to the "recommended" pressure.The only reason I can think of that they would do that on purpose would be if a lot of people were getting their rims damaged from impacts like large pot holes when the pressure was lower. Low profile tires like that leave the rims more susceptible to that - and increasing the pressure can help reduce the chances of damage to the rim directly - but it transfers more of the hit to the suspension... everything's a compromise I guess.John

[KennedSR]

Yeah I actually have a set of 16's just for the winter but with the price of the 18 inch tires I am really debating switching down to them permanently after these tires wear out. That may also make sense since PA is known for pot holes a plenty and PennDot is less than enthusiastic to fix anything.

[vibenvy]

I rotate the tires and change the oil on both our 2009 Vibe GTs, so the dealer has never done anything but recall and/or warranty work on them. Therefore our tires are always at 32 PSI. Just one more reason why I don't like taking any vehicle to a dealer unless absolutely necessary.

[goodvibesGT]

18's are not cheap! I finally broke down and bought some AC Eagle - original equipment online and ran me over 500 for all 4 including mounting. Kind of crazy for a fuel efficient vehicle and decent handling. Rotate... Rotate... or you'll be swapping them in 20K. 16's are a good alternative - may be my next tires and wheels when these go.

[09vGT]

I keep mine at 40.

[robinhayman]

Glove box pressure is too low. There's a bunch of threads why, but it has to do with the difference in tires now verses 35 - 40 years ago. I've seen a lot of threads like this over the years. Most people will say 27-30 in the front, 30-32 in the rear, with a 3-4 pound differential front to rear, the lower pressure being in the front. But I've seen a few that just run 30 or 32 all the way round and like it. I run 28 front, 32 rear.32 psi is great for street, but not if you are trying to hook on a drag. You want more sidewall flex. I'd cut them down to 24 and then go down from there based on your 60' times.

[bluneon]

there are 3 possibilities:

the mechanics tire pressure gauge is off, and yours is accurate
your tire pressure gauge is off, and the mechanics is accurate
OR
both tire pressure gauges are off, compounding the issue

overinflated tires will offer completely different driving dynamics than if they were properly inflated. vehicle will veer around on the highway, especially when they hit ruts in the road; the ride will also be extra bouncier and you can also distinctly hear the overinflated tires 'bouncing' on bumps in the road. they also offer less contact patch on the road because the centers of the tires are now bulging out; this will adversely affect stopping, cornering and heat dissipation. the possibility of hydroplaning will also increase. the supposed benefit of better fuel economy outweighs these problems?

be sure to have and use an accurate tire pressure gauge.