3.3TT Rear tire pressure

[RUFFSTUFF]

So what tire spec do you go with when you replace your tires and you didn't get OEM?

 

[MerlintheMad]

So what tire spec do you go with when you replace your tires and you didn't get OEM?

The same. Any tire made for these rims are going to have the same psi specs on the Stinger; Kia did the specs and the tires comply.

 

[RUFFSTUFF]

Aha...

 

[eflyguy]

The same. Any tire made for these rims are going to have the same psi specs on the Stinger; Kia did the specs and the tires comply.

That's actually not correct, but it's close enough for most.

 

[MerlintheMad]

That's actually not correct, but it's close enough for most.

Can you point to exceptions? I don't know of any myself.

 

[RUFFSTUFF]

Well for one it kinda ignores any variations in tire construction and relies on an assumption that all tires of the same size are, in fact, the same. But it's your opinion and I'm sure you're good with it.

 

[MerlintheMad]

I just know what my rim and tire guys told me: 40 psi is what they inflate to unless the vehicle says higher. So tire differences are not the criteria; vehicle spec is what decides.

 

[app_master]

I also refer to the 4psi rule, inline with the vehicle tyre placard as the starting guideline. Certainly if going after market rims or tyres both in different sizes and brands, then you need to speak to the experts fitting them ... but my final check is still the 4psi rule thing. Got into this habit when hitting the bitumen after 4wding, as trips load can vary significantly depending on towing and gear onboard.

Here is how it works ... cold pressure set, then 30min of moderate driving (on road), recheck the pressures should be up 4psi. If higher then add more pressure when cold, if lower then reduce the cold pressure. Seems to work for me, but can take a few drives/stops to work it out.

From what I recall when adopting this check ... it was something from Michelin when they developed steel belted tyres.

(I'll add "tire pressure" keyword here for our usa fiends trying find this by search )

 

[RUFFSTUFF]

I just know what my rim and tire guys told me: 40 psi is what they inflate to unless the vehicle says higher. So tire differences are not the criteria; vehicle spec is what decides.

But your tire guys are ignoring the spec aren't they?

 

[MerlintheMad]

But your tire guys are ignoring the spec aren't they?

Not ignoring; modifying. They say 40 psi is better because it makes a high aspect ratio tire less likely to receive a damaged rim from potholes; while not be over-inflated. So firmer but not prone to center tread wear. I'm sure if the first priority were performance they'd probably be under-inflating according to the psi spec on the car.

 

[itguy61]

Over inflation causes center wear on tires. Under inflation outer wear. Deviate from car manufacturers recommendation at your own risk. The tires on my car were at the wear bar in the center and had 4/32 at the outer edge. Previous owner here on forum says they were inflated to door placard. I would be interested to know if others with this particular tire get excessive center wear in the center at the recommenced pressure. Running a higher pressure would have made it worse.

I changed to Michelin Pilot AS-3 tires so I will see if they wear differently.

 

[MisterMac]

My view is this. The manufacturers, both tires and car, know best. If you study, you can come to Understand what psi to use if you change tires from stock sizes, load ratings, etc (both curb and with passengers or other cargo.)

Otherwise, I truly don't relate to screwing around with the only four pieces of the auto that come into consistent contact with the ground.

Seems like fools folly to me. Those tire guys aren't going to take care of your family when you bite the big one.

Nonetheless, live and let live. Just hoping I'm nowhere near you when you blow a tire from over inflation, under inflation, hydroplaning, slippage, or abnormal wear.

 

[itguy61]

I have not worked in the tire business since 1995 but one thing was the same then, all the tire manufacturers we dealt with said to inflate tires to pressure specified by the car manufacturer. I was always perplexed at the number of people who would argue with that despite all the documentation verifying that. The tire pressure on the sidewall is the MAXIMUM the tire is rated to hold, not the recommended pressure for all cars that use this size.

 

[RUFFSTUFF]

Not ignoring; modifying. They say 40 psi is better because it makes a high aspect ratio tire less likely to receive a damaged rim from potholes; while not be over-inflated. So firmer but not prone to center tread wear. I'm sure if the first priority were performance they'd probably be under-inflating according to the psi spec on the car.

Making it up as you go along... got it. Thank you for the feedback.

 

[RickFL]

One owner. Meticulously maintained 15.5k. I inflate to 36 psi per vehicle placard. Just had a nail patched in rear tire. Fronts were 7,7,7. Rears were 6,3,6!!! This is NOT a previous owner or overinflation problem.

 

[MisterMac]

One owner. Meticulously maintained 15.5k. I inflate to 36 psi per vehicle placard. Just had a nail patched in rear tire. Fronts were 7,7,7. Rears were 6,3,6!!! This is NOT a previous owner or overinflation problem.

For summer tires, you're doing well

 

[ZyroXZ2]

I'm anal when it comes to tire pressures: all four tires are inflated to EXACTLY the same pressure (meaning, there is no discernible difference in the needle's position at all).

I've done 36 in the winter, 35 in the summer, and yet the center tread on my rear tires is clearly wearing faster. I rotate my own tires, and despite my following specs, it still wears at the center quicker. This may be more related to factory suspension alignment specs and design than anything else. Meaning, it may be how the suspension flexes, the arch of the curve between various loads, etc.

 

[Manaz]

Cold to warm tyre pressures are generally about 10% different.

Recommended pressures on a given car are set by the car manufacturer, not the tyre manufacturer. The car manufacturer chooses tyres that for their design requirements - most tyres will have a range of pressures they work over, including a max pressure that you should generally be nowhere near.

Any dealership delivering a car with tyres at 50psi when Kia specify < 40psi should be hauled over the coals.

I tend to run between 32psi and 36psi cold on my regular passenger-style vehicles - SUVs tend to be different, not least because they run high-profile tyres. I don't generally vary pressure front to rear for driving on public roads, maybe sometimes for the track (particularly with a RWD car, where lower rear pressures help power-down, higher front pressures help steering accuracy).

 

[MerlintheMad]

I'm anal when it comes to tire pressures: all four tires are inflated to EXACTLY the same pressure (meaning, there is no discernible difference in the needle's position at all).

I've done 36 in the winter, 35 in the summer, and yet the center tread on my rear tires is clearly wearing faster. I rotate my own tires, and despite my following specs, it still wears at the center quicker. This may be more related to factory suspension alignment specs and design than anything else. Meaning, it may be how the suspension flexes, the arch of the curve between various loads, etc.

I've been watching my rear Pilot Sport tread wear. This center wear on the rear tires seems to be a consistent observation on these cars. Last week the depth showed 6mm across both front tires, and the rears were 5mm and 6mm on the outside and 3mm on the center.

I've reduced the rear tire pressure by c. 3 psi. When I start up cold now, the psi shows c. 39 front and 37 rear.

(edit: later: after c. 1.5 miles, this morning, the TPMS showed 40, 40, 37, 37)

 

[SKStinger]

I’m running 33 cold psi on the stock Michelin’s to try and mitigate the centre wear.

So far they are wearing evenly.