Ok I know this is going to seem like a silly question but gonna ask anyway. So when I picked up my RDx a few weeks ago, brand new, I noticed the tire pressure was like 43-45. Thought that was high and according to the door it is. Max tire pressure according to sidewall is 51. I let some air out and now around 40-41. I know it is above the recommendation on the door jam but I love the ride. I was reading another thread, I think it was about the Acura Link App and somebody noticed the tire pressure and was also around 40-41 and made the comment that they were way over inflated. I was under the impression the door jamb pressures were for the best ride but as long as mine are under the actual tire limit, does it really matter??

thanks

 

That manufacturer recommendation no doubt considers ride, handling, tire wear, footprint, and safety. Keep in mind that tire pressure builds with heat, and 41 cold is likely 45ish hot. And I also believe the max rating is a temporary max for seating the tire on the wheel. I don't know if you're still within safe operating range, but you're certainly closer to the margins.

 

Almost all manufacturers over inflate the tires for transport/storage. The dealer IS SUPPOSED to reduce the tire pressures to the recommended pressures, as stated on the door jamb sticker. It seems that it is an often over looked step in the PDI. I find it pathetic that the dealers are skipping this important step, makes me wonder what else they are skipping. And this is not unique to Acura. I just don't get it.

Feel free to keep your tires at 40 PSI, but as has been mentioned by DJA123, this pressure may leave you with pressures over the max.

 

May I recommend 35 PSI at all four tires? Enjoy.

 

yes I accept 35 psi on all 4 cold tires ...

 

Yes, much nicer ride and less road noise too. As mentioned above, mfg ships the cars with the tires really pumped up so they are less likely to get flat spots when parked on the lot for extended periods or maybe to help seat the beads. The dealer was supposed to adjust the pressure before you got the car but it seems they rarely do.

Go with the number indicated on the door post. ( or was that the gas door?? )

 

I tried 33, 34, 35, 36, 37psi because I could not help myself. When my wife drives it I set it to 33 because her commute runs on some pretty crappy roads. I have a most highway commute and 35 works great. Higher than that makes the ride not as smooth IMO. I did not bother going over 37psi because I did not like the ride.

 

I figured out why so many RDXs (and others) are delivered with over 40 PSI in the tires. See what I BOLDED below....
This is from the "TQI" (Total Quality Inspection) formerly known as PDI, or Pre Delivery Inspection...:
"To prevent flat spots during vehicle shipping and storage, the tires are inflated to over 40 psi. If the vehicle is going into dealer storage, leave the tire pressures at 40 psi until it is sold. When the vehicle is moved to the sales lot or is sold, adjust the tire pressures. Turn the ignition to ON. Set the pressure in each tire to the recommended value listed on the driver's doorjamb label, and check it with a hand-held gauge. If you are in a cold climate region, make sure the tires are at the same temperature as the outside air before adjusting the pressures, otherwise the Low Tire Pressure/TPMS indicator may come on in cold weather. Test-drive the vehicle for at least 1 minute above 22 mph. If the MID does not show the tire pressures, make sure you completed the test-drive as specified. Be sure to check the pressure in the spare tire (if equipped).

So, when they sell the vehicle, it gets a wash, and they are supposed to lower the tire pressures at that point. Yeah. NOW I know why so may new cars are delivered with over 40 PSI in the tires.

 

That makes sense. I think in my case, they just got the car in, was still wrapped in plastic and it was an oversight.

 

OH, also: " New Tire Pressure Sensors Beginning with the 2021 model year RDX, Base and Tech trim levels will come with rubber valve stem tire pressure sensors. Advanced and A-Spec trim levels will keep their metal valve stem tire pressure sensors."

 

how much of a difference does this make?

 

I have absolutely NO idea. Just thought I would share what I read.
Perhaps it's cheaper to make the rubber ones?? But if so, then why not use them all across the trim lines?
Beats me.

 

Are we at the point where valve stem material is applied based on trim level? Yes, apparently we are.

​​​​​​"I'm looking at the new RDX and can't decide if I want the Tech or the Advance trim. Oh wait, the Advance has metal valve stems?! Sold!"

 

Yeah.....I don't get it If they are saving a few cents per car, just put the rubber ones on all trims....

 

Just a note:
Tire pressure is a big issue, really. First of all, NEVER look at the pressure on the side of the tire. That is a MAXIMUM pressure the tire is rated to safely hold and has nothing to do with what your vehicle actually requires. As I told a class once, that size tire fits on a wide range of vehicles of different weights. How could the tire maker know the final application?.
Pressure that is too low or too high causes tire and handling problems. Too low and the tread buckles and rolls and you wear out the side of the tread. But worse than that it causes excessive flexing of the sidewall and this can cause the tire to run hotter and even fail. (Ask Ford and Firestone about this, they had this issue with Explorers and got some major law suits out of it).
Excessive tire pressure will cause the tire to lose some of its contact patch with the highway. While this may give you a tire that will run cooler and use less fuel the price you pay will be a tire that wears the center of the tread more and which will not grip the road nearly as well, especially under conditions like a wet surface.
Tire pressures are normally determined by testing to find the best balance between all these factors: Tire running temperatures, proper contact patch, economy (while working properly), and ride quality.
Always set tire pressures while the tires are at "ambient temperature of the surrounding air". (Or...what is refereed to as a "cold tire".) Tires will warm up and the pressures do increase. Don't set pressures while they are warm.
The sticker on the vehicle is required by Federal law. Its the best pressure to go by. Personally I have found that you can go a pound or two higher but not more. As you add weight to the vehicle you may want to increase the pressure. Whenever I am driving any distance with a loaded vehicle I will feel the tires while stopped to make sure they are not getting warm. Hot tires are a clear sign the pressure is lower than needed for the current weight. Lower pressures are never advised as they will cause these higher temperatures to develop and can result in premature tire failure in extreme cases. Some people think lower pressures give them a smoother ride, which it can, but again, the price is worse performance of the tires and possible tire failures.

 

has anyone set their tire pressure at the recommended rate prior to long drive? I set mines to 35 PSI cold and on a long trip they went up to 37-38 PSI.

I'm going for another long drive in 2 weeks, thinking of dropping them down to 33 PSI cold. so that when the tires heat up they wont get as high. anyone try this? I want to drive and preserve my tires for as long as possible, im rotating every oil change, but I've only had 1 change, m at 9500 miles, probably when I return from this trip I'm sure I'll need to change the oil and rear differential.

 

Another question: if the tire pressures are too high, is it possible to just let the air out and have the car indicate when the pressures are where they should be? Or do I need to get a tire pressure gauge and let some out and then recheck it, like with any other car?

 

RDX has tire fill assist or you can look at the gauges
https://owners.acura.com/utility/dow...ing_System.pdf

 

Right, but is "tire fill" just for when you are low and adding air? Or can I just let the air out and it will notify me when I get to the correct pressure? Like I don't want to be letting out air and then it's flat and I realize it never warned me.

 

i was letting air out of my tires the other day and noticed it didn't update the pressures on the screen. if i turned the car off and back on, it would be updated.
maybe it would update if i waited long enough, but i didn't have the patience to find out.

 

OK, thanks, that's what I thought. I was hoping I could just let the air out and it would tell me when to stop.

 

It is normal for the tire pressure to rise as you are driving it. don't let out air as you are describing. Wait for the tires to get cold, like a few hours after driving or later, check with a quality gauge, fill to the prescribed 35 or whatever you want (some like it a bit higher), and leave it. Check it every month or two to compensate for the change in environment, like fall to winter. You will be putting a little bit more air in winter, and a little bit less in summer, but the tires will be showing the same pressure.

 

Its normal for tire pressure to rise while driving. That was factored in when the recommended tire pressure was set. Only set tire pressure on a "cold" tire; that is, after the vehicle has been at rest for several hours. (over night is best). Don't be concerned if the pressure goes up a few pounds while driving, its normal and calculated in to the recommended pressure settings. One tire may even be a pound or so higher or lower than the others, that too is normal for several reasons. (Pressure sensor variation, type of driving where vehicle dynamics may cause one or more wheels get a little more work out than others, load in the vehicle, etc.)

You tires can safely operate at a much higher pressure than you might think. While this is not recommended it is a safety margin for tries that get a little hotter and drive up pressures. I like the dash display but the professional in me demands I always set pressures with my hand gauge. (For many years I have used my nice German Dräger <no longer available> unit whick I prefer to use just because I totally trust it and its easy to read).

 

Thank you all for this info. I assumed my new RDX just had tires that required 42 psi. as it showed on the pressure monitoring display. Let some air out, rides nicer now.

 

There is a label on the driver's door jamb that shows what the pressures should be.

 

Thank you, yes I knew that. What I didn't know was that the dealer would sell me the car with such over inflated tires. Didn't know that was a thing, I assumed a brand new car was good to go the way it is when I drive it off the lot.

 

NOt surprising. I have found that happening with other car owners as well. I believe the cars come like that to the dealer. Unfortunately, good skilled trades are becoming extinct or hard to find.

 

Stop behaving like having tire pressure over what the door jamb states is going to be dangerous or cause an instant blow out. You're fine. Even the "Max" tire pressure on the sidewall by the tire manufacturer is conservative. As stated prior, the recommendation by the manufacturer on the door jamb takes into account ride, handling and gas mileage, among other things. Being 5-10psi over isn't going to hurt anything, except maybe your backside. As far as hot vs. cold, the most I have seen the tire pressure go up is 4psi while driving on hot summer roads, less in the winter time (usually no more than 3psi, usually only 2psi). If you're doing very spirited driving, probably a bit more. 40psi, you're fine if you enjoy the ride like that. You'll get slightly better gas mileage, I'd just keep on eye on the tread and make sure you're not wearing out the centerline of the tread more quickly. Again, I'd be flabbergasted if 40psi actually did that.



Just a story as an aside, if you're still with me, when I used to wrench on cars. Regular customer came in after working in the city and asked me to check to see if there was a leak in the tire because his TPMS had gone off. He filled the tire up that looked low after sitting all night at a gas station closer to his house until the light went off. Then went to work, came back and stopped at my shop ... nearly 100miles round trip. Very nice guy. Took the wheel off and found a screw, but it was basically at the cup of the tread and the sidewall, plus his tread was at the wear markers to begin with. Told him it wasn't safe to plug/patch it due to the location of the screw and told him a place he could get tires at a good price and quick service. I would have done it for him, but it would have taken a lot longer and probably been more expensive for him. He thanked me and asked if I could just check the tire to make sure it wasn't low. Of course. Bam. 80psi. On a passenger tire rated to only 40-something, driving on the highway, nearly 100miles, on an old worn tire. And this was after it had leaked out some, so he probably had close to 100psi in that sucker. I was shocked he didn't have a blowout. Told him, we laughed, took some air out so he could safely make it to the tire shop on the other side of town. Since then, I've realized that tires are way more resilient than people give them credit for. I'm not saying to go and do that, but these things are strong. You're more apt to destroy a tire by running it low on pressure than high.

 

you are right, they should have checked the pressure before you left the lot. They keep it high like that so when transporting and sitting, the car tires do not get flat spots. At least it lessens the possibility. I saw the same when I left the lot.

 

Ah yes, along with that, it's probably safe to say that a pre-delivery inspection wasn't done on your vehicle, or at least not a very thorough one. Checking tire pressure is one of the most basic checks done before passing it off to the customer.


It's certainly not the same caliber vehicle, but I really enjoy this guy's videos. Unfortunately, it seems like Porsche is shutting him down from posting more videos:

 

Add me to the list. Picked up my 2021 Advance Saturday, never thought to check before leaving the dealer. At home (knowing) the pressure would be high from driving the pressure was 45. I let the tires cool down for the day and later reduced the pressure to 35 psi with my tire gauge. Same reading with the RDX.

 

I took this advice and you were correct EXCALIBUR1. At least I noticed a bit of improvement in the noise factor of my Conti's + a smoother feel overall even though the car had an exceptional ride already. It's the little details that matter in life. The Conti's were between 42-45. Anyway, thought I'd let you know. Thanks.

 

I upgraded to 20" wheels and tires and applied the door jamb sticker for 20" wheels from the A-Spec.

The 19" tires have a manufacturer recommended pressure of 33 psi and the 20" tires are recommended to be 36 psi.

I run at 36 but, every time the dealer services the car, they reset them to 33 because it's a Tech model without looking at the placard.

I definitely lose 1.5 mpg running at 33 psi and have to go back to 36. 33 does not improve the ride at all.

 

Interesting! I generally have run tires about 3-4 PSI over MFG door jamb recommendations, but in my RDX, I have tried to keep them at 33 (Advance 19") I may up them to 36 and give them a try. (they were at ~44 PSI when I took the new car home)