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As the air inside the tire heats up, it expands, and your TPMS warning shuts off. The difference may be a factor of how much one car's tire air pressure is lower than the other i.e. a tire that is further below its rated pressure due to cold will take longer to heat up enough that the air expands back to its normal pressure. This can be a factor of the temperature when the tires were last filled or topped off if it was very hot, the initial pressure will be read as higher and will compress more are it cools, while a tire filled in the winter, may not trigger the TPMS at all due to cold weather, (but could slightly over pressurize in the summer), or one car may have lost some air from the tires. It can be a factor of TPMS sensor sensitivity or the acceptable pressure range for that car. It can be a factor of tire size and composition. Larger tires have a great volume of air to heat up an expand, so they will take longer to heat that much air. Wider and softer tires will have more road friction and will therefore generate more heat more quickly. It can be a factor of the speed you are driving. With my truck the TPMS warning will stay on if I drive a lot at 25 mph while it goes off quickly if I jump on the freeway. I do not know, but I suspect a lot of braking will transfer more heat into the tire than road friction will. Braking generates immense amounts of heat and some of that heat likely transfers to the air inside the tire. Keep in mind the difference n pressure due to expansion an contraction of air is pretty minuscule. If your tires a more than ballpark 5psi low in the morning, you just have low pressure and need to add some air (and then watch for leakage). I am estimating the amount of normal contraction based on what I see with my tires.
Also it is possible on of the cars had the summer air changed out for winter air. Winter air works much better when it is cold outside. Have you had winter air installed yet? (This is a test).
Just noticed that the TPMS on my 2014 Ford Focus usually only goes off after I've driven about 10 miles.
On my wife's 2005 Explorer it usually goes off first thing in the morning. Usually goes off after a couple of miles as the friction causes the air to expand.
Why the difference? Does the 2014 have "new technology" that ignores initial low pressure when it's cold out, and doesn't give the warning right away? Personally I'd rather have the alarm early so I can stop at a convenient gas station rather than having to get off the highway and back on again.
maybe you need to find your PSI range.
Say for example, that your vehicle suggests your tire pressure is supposed to be 32PSI. That could be what your TMPS threshold is set at. If you fill the tires to 35 or 36, which wouldnt over inflated, you have enough room for expansion and contraction without the TMPS going off. The manual will tell you when the TMPS is supposed to go off.
What I wonder is if the new TPMS sensors warn you for over inflated tires. Gotta check my manual.
Just noticed that the TPMS on my 2014 Ford Focus usually only goes off after I've driven about 10 miles.
On my wife's 2005 Explorer it usually goes off first thing in the morning. Usually goes off after a couple of miles as the friction causes the air to expand.
Why the difference? Does the 2014 have "new technology" that ignores initial low pressure when it's cold out, and doesn't give the warning right away? Personally I'd rather have the alarm early so I can stop at a convenient gas station rather than having to get off the highway and back on again.
Supposedly this is why it became popular to sell nitrogen to inflate tires with, because there's less fluctuation due to temperature than regular air.
I keep my tires at 42 PSI (9 PSI below max sidewall pressure) for a nice performance safety margin.
When it gets cold, even from 70 down to freezing, the pressure isn't low enough to start setting off TPMS warnings.
The actual bursting pressure of a tire with even a C-load rating is well north of 100 PSI absent any manufacturing defects or damage. Always keep it below sidewall ratings and you'll be okay. If the tire bursts below the sidewall rating, it wasn't due to there being too much pressure in it.
Monitor your tires monthly for treadwear issues due to over- or underinflation. I run mine so high because I have a rather heavy vehicle on tires with a C-load rating. I have not had adverse treadwear over 50,000 miles. Not exhibiting disproportionate wear in the center of the tread.
I hate TPMS sensors... Mine right now is faulty in the front right tire and they want $250 including labor to fix it.
Every winter the light goes on when the temp falls below 32F so I fill it up with higher air pressure to compensate. Then when the temp rises (sometimes on the same day) the light will start blinking due to too much pressure.
I will drive between 4k - 8k elevation and in winter the temperature disparity may be between 50F high and low single digits low in the same day. You just have to learn to ignore the TPMS during these conditions.
I keep my tires at 42 PSI (9 PSI below max sidewall pressure) for a nice performance safety margin.
When it gets cold, even from 70 down to freezing, the pressure isn't low enough to start setting off TPMS warnings.
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Youre not supposed to fill your tire by the tire sidewall pressure, you use the recommended pressure in the doorjamb of the car. The tire manufacturers dont go by the weight of any cars. At 42PSI as a normal pressure, yours are overinflated and will cause premature wear.
I hate TPMS sensors... Mine right now is faulty in the front right tire and they want $250 including labor to fix it.
Every winter the light goes on when the temp falls below 32F so I fill it up with higher air pressure to compensate. Then when the temp rises (sometimes on the same day) the light will start blinking due to too much pressure.
I will drive between 4k - 8k elevation and in winter the temperature disparity may be between 50F high and low single digits low in the same day. You just have to learn to ignore the TPMS during these conditions.
You're getting ripped off. A sensor, if your tire even has one, is about $40 to $50. Are they possibly recommending you replace all of them at that price? Unless you have an exotic car. I've driven in varied conditions and the only time I even had an issue was when I drove from Arizona to Alaska in November. I had new tires that were at two psi over the recommended door jam sticker pressure. This was at about 75 degrees. By the time it was minus 21 degrees, the air had contracted enough to set off the TPMS. I just added more air and all was well. When I drove from Alaska to Arizona, it was the opposite. Tires at two psi over recommended psi leaving Alaska and they were at six psi over recommended when I got to Arizona.
Youre not supposed to fill your tire by the tire sidewall pressure, you use the recommended pressure in the doorjamb of the car. The tire manufacturers dont go by the weight of any cars. At 42PSI as a normal pressure, yours are overinflated and will cause premature wear.
It never ceases to amaze me at how many people don't know this. The psi on the tire is just the never exceed pressure. Since any given tire can be used on many different vehicles, you should always go with the manufacturer's recommendation, which as Harry Hemi stated, can be found on the doorjamb sticker. The fix for this is to put a minimum and maximum psi range on the tire with a warning to inflate to the manufacturer's recommended psi.
It never ceases to amaze me at how many people don't know this. The psi on the tire is just the never exceed pressure. Since any given tire can be used on many different vehicles, you should always go with the manufacturer's recommendation, which as Harry Hemi stated, can be found on the doorjamb sticker. The fix for this is to put a minimum and maximum psi range on the tire with a warning to inflate to the manufacturer's recommended psi.
Yes you should go by the door jamb recommended by the manufacturer.
But the "MAX" psi on the tire is not the never exceed pressure. That is the PSI needed for the tire to provide its max load rating. They can handle pressures well in excess of that up to around 200 psi.
People sometimes ask if they should put less air pressure in the summer. They reason that since the natural air pressure increases due to heat while driving is more pronounced when it's hotter, then it would be better to put less air pressure in them. Though this makes sense, it is not correct. Tires are designed with this in mind, and if you put less air in, the tire will flex more and will actually build up more heat! Since heat is one of the primary enemies of tires, less air in the summer is definitely not better. As far as winter running goes, we are asked if they should put more air in since the pressure drop when it's cold. The answer is no again. However, anytime your tires get low, you should add air, and since tires lose air pressure naturally over time. you should always check your tire pressure every month or two.
It may seem odd that the majority of modern car tires take 44 or even 51 psi max pressure, while most cars specify 35 psi or even less. We use the extra capacity to compensate for winding road driving and weight bearing, as stated above. However, the real reason for this has nothing to do with either: When cars are driven above 100 mph, the air pressure in the tire decreases, and more air must be put in the tire to compensate. So the real reason for the higher capacity in these tires is actually for driving at speeds over 100 mph.
The physics of this is the ideal gas law. PV = nRT. T is temperature in kelvin). P is pressure.
70F is 294 kelvin
32F is 273 kelvin
About an 8% pressure drop. That's enough to trigger the TPMS icon on the last 2 cars I've owned if I haven't checked tire pressure since the summer tires went on in April. My last two cars, you can see the pressure on each wheel through an instrument plugged into the ODB II port. On the instrument cluster, you just have an idiot light icon that looks like a flat tire.
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