I live in Northern California where it is normal to have 20 to 30 degrees F intra day temperature variation. This means that if I set the pressure to what is on the door jamb on a warm afternoon, I could end up triggering the TPM on a really cold morning. Conversely, if I set it to what is on the door jamb on a cold morning, I could end up with pressures that are 3-4 psi higher (i.e. rock hard ride) on hot afternoon.

To avoid triggering the TPM, the service guys set it to 36 psi which is already too high and as temperatures get warmers, it gets even higher. Today the TPM reading on the dash was showing 39 psi in 2 of the tires, 38 in the other 2.

How do you guys deal with this? Would nitrogen help? If so, what would be a recommended place to get it.

I'm hoping to find a consistent ride by keeping pressures relatively constant. Right now if we have 35 degrees and 75+ degrees temperatures within a week I don't go from acceptable ride quality to shocks up spine. Conversely, I would go from acceptable to triggering the TPM.

I'm off to go remove some air from the tires. I have a bad back so messing around with pressures is physically very painful.

 

I prefer not to over think it, like I'm on a NASCAR track and I need a 1/4 psi difference between my outside and inside rubber.

I set the pressure to 33 psi on a cold morning, at any time of the year. If the pressure rises 2-3 psi as I drive, it's not a problem.

Although, I understand airing up a tire can be rough on a bad back. I also have back problems but not to the point where a hard ride in my RDX affects it. I always find it comfortable.

 

Just so you know, the TPM is a convenience thing and doesn't effect any computer functions.

 

The thing that bothers me is the warning that pops up every time the car is started. And I’m also concerned about being more susceptible to getting a flat.

 

The automotive engineers choose the tire pressure based on longevity of the tires, comfort, and handling. A soft tire will provide a very soft ride, but too low can cause tire failure. Higher pressures will result in precise handling , but may give a bumpy ride. Personally I set my tires about 2 PSI higher than the door sticker because I like to drive "enthusiastically"

The thing that destroys tires is the constant flexing of the sidewalls caused by under inflation. The flexing not only causes metal fatigue of the steel belts, but also produces heat which can damage the rubber. It also causes uneven tire wear.

So priority #1 is to set your tires to the proper (i.e. door sticker) pressure at the coldest part of the day. If you do this , you should never see the TPMS warning light come on. The 36 PSI the service guy set them to, was a little excessive, and probably not done when the tires were cold.

As you drive, the pressure will increase. In fact the front tires will increase faster than the rears, because they are carrying more weight, and are constantly moving left/right as you steer. However an increase of 3-5 PSI is normal, and it will not damage the tires. It is factored into the engineers design.

In fact, if you look at the sidewalls of the tires you will see a "Maximum Pressure" rating. This is the maximum pressure the tires will hold before damage would ever occur, for example a blowout. This pressure varies with the brand of tire, but is should be 40 PSI or more. By the way, some people have been known to set their tires to this pressure just because it is stamped into the sidewall.

So the 3-4 PSI increase that you see during the day will not cause damage to the tires if the cold pressure was correct.

Using nitrogen may help very slightly, but since air is 80% nitrogen to begin with, the change would be almost unnoticeable.

 

Agree with everything you said....except...

Using Nitrogen will only help if you paid the dealer more than $90 for it.

 

I set the pressures twice a year. Once when we've reached a representative temperature for the summer months and once when we've reached that temperature for the winter months (when it's in the mid-80s and when it's in the low-30s). Then just take what I get in between. If you have a wide variation on individual days, just set it when you're at the cooler of the extremes and let it go. Temperature varies about 1 psi for every 10°. It's never going to be exactly right.

The main "benefit" of nitrogen is that the molecules are larger and therefore less likely to leak out. Air is mostly nitrogen anyway, and I haven't had any trouble with air leakage in years. It does help to buy valve caps that have O-rings in them, since Schrader valves can sometimes be leaky.

 

Over the last 6 months we’ve had temperatures from 110 down to 55, and I’ve had the tire pressures vary between 38 and 27! Today I got a low pressure warning for one of the tires showing 27. Fortunately I was scheduled for service so they’ll be putting in more air to deal with temperatures dropping even further over the next 6 months.

 

A rough rule of thumb is a 1 psi change for every 10 deg change in temperature.

Personally I don’t like the dealers or service centers to check tire pressures, and of they do I always double check afterwards. Almost invariably they over inflate. The RDX for instance is supposed to be 33 psi, I like it at about 35, but the dealer puts it at 40. I once thought it my gage but several read the same thing.

 

Mine puts 35. I like it at 33. But I can live with 35, especially since I expect it to drop 7-8 psi as the weather cools. The difference between day and night temp here is 30 degrees. By the time we get to Feb, difference between day time temp now and night time temp then will be about 50 degrees.

 

ai
Easy to avoid the low tire pressure warning. I fill up to 39psi (cold tire pressure), as I’ve driven from 65 degree to 15 degrees and that seems to work best. Plus, I like a slightly firmer ride and helps on the freeway.

Plus, pick up a battery powered air inflator like - Fanttik S100 APEX Powerful Portable Air Pump & Tire Inflator with Power Bank - keep it in the vehicle so if you get a low warning, no need to search for a petrol station that has a working air pump.

 

Anything over 35 feels too hard here. Roads are of poor quality — too many imperfections and potholes.

 

Also depends on which trim. The A-spec should be 36 psi cold, which usually ends up being closer to 40 once the tires are warm. Whenever I top off at Costco, I just set the machine to 40.