Yeah, there is some of that. I am somewhat remorseful for having sold my 03 Avalon.
Have you checked to see if 16 inch rims fit from the regular Avalon ? I bought a Venza with 18 inch rims but use 17 inch for my winter tires. They are pretty standard in the Toyota lines and should be very easy to find one and test fit. I still don’t know why you are whining about 35 lbs…and don’t just stick with 32lbs. The recommended. I doubt you get a 50 degree drop. My summer Venza rims are 18 inch and I pay them no mind at all and keep them at 32 lbs. when the temp is at it’s coldest. Then they will go up when warm by just a lb or two…check the Air pressure first thing in the morning at 32lbs…you are good for the day.
A co-worker of mine suddenly started missing work meetings. When asked why, he said it was b/c he kept getting flat tires. He’d bought a new car, a sporty model, and it had this type of low profile tire where the tire would go flat just going over a bump. His solution – since he wanted to keep his job – was to sell the car and buy one with normal everyday wheels and tires.
Hearing nitrogen filled tires help avoid that, Are they nitrogen filled tires? not that regular 82% nitrogen in regular air should be to much different.
The batteries in the sensors do not go bad very often. I have a 2006, all 4 sensors work, and as far as I know, none have ever been replaced. (I got the car used about 4 years ago)
Your 4.6" sidewall height is very common these days.
The 1 psi per 10 deg F assumes constant V.
I think that I missed the day of school when they were discussing; Gas law: P = (nR) T/V
Or that’s the physic’s class we all cheated in.
Either way, I think the Mister Mellot needs a better air gauge.
These sensors must give you some leeway.
If the door says to keep 32lbs in the tires and you do, I’d just raise to 34lbs and hope it keeps the sensor off.
Your gauge may be off by 2lbs!!!
If it’s a pencil gauge I’d throw it out and get a dial or digital one. I never could get those pencil gauges on straight and always lost 20% of the air I just put in…trying to get it on straight.
I just threw out three of those pencil gauges that have been in the drawer for years. I would have given them away, but why give a broken gift to somebody.
Yosemite
Ok here’s a dumb question .
Someone mentioned a Humvee and I’ve heard that you can raise or lower tire pressure while on the move.
How in the world do they do that. I’d think the midget would get the air hose tangled.
My apologies to any midgets!!!
Yosemite
What can I add, except I’ve found when I’ve made a mistake to correct it right away and take the punishment quickly.
Re: Humvee…I believe the air goes in through the hub spindle and wheel with appropriate rotating seals
I suspect there is a lot more going on here. What Melott describes just isn’t a function of the aspect ratio of the tire.
He correctly identified that the Ideal Gas Law is at work - and unless there is some leakage, the 30 degree drop in temperature should have resulted in a 3 psi drop in pressure. In other words, the laws of Physics aren’t different for different tire sizes.
While I am not a big fan of lower aspect ratios, they are not the cause of the conditions being described.
Also, the air volume in lower aspect ratio tires is NOT smaller (if you take load carrying capacity into account - which the way car manufacturers decide what tire size to use.)
Actually, the load carrying capacity is the product of the air pressure and the surface area in contact. So, when the Dum&*%@ flat tires are in use, the volume of air (product of area time height, ignoring bulge) is smaller. The ideal gas law is a good approximation, but it works as was said assuming constant volume. I am thinking maybe there is a departure of some kind from the ideal gas law. I don’t think it is a leak, because all 4 tires read exactly the same, just as they did previously, except much lower.
All that being said, what is a good digital tire gauge that doesn’t cost so much that only a tire shop would want to buy it? I had one, and it was a disaster. Right now I am using 2 pencil gauges that agree with one another and my mechanics’s shop gauge.
Hey @melott … I don’t think changing the tire diameter will make much difference. I have 215/55R16’s on my HHR. I normally run 32 psi but early in a cool morning…I usually have 28 psi and after a short run on the interstate I have 34 psi according to the TPMS. Keep the TPMS and your stock tires and wheels. I railed about TPMS for years but now…I’ve come over to the dark side and rather enjoy checking my tire pressure from time to time with the “info” button. I use a Victor dial gauge and 2 pencil gauges that agree with it. I find the pencil gauge easier to use because the dial on the Victor does not stay in place after the reading.
I think that my tpms (sounds like a disease or time of the month) only works as an idiot light, coming on if they get too low.
Here’s one possible departure from the ideal gas law: It’s been a wet year here. If the air in the tire were saturated with moisture at the last reading, and it all liquified on yesterday’s cold morning, that could account for 1.5 psi of lowered reading. (3% of the roughly 45 psi absolute pressure in the tire). That combined with the 3 lb lowering you get from ideal gas law would explain my reading. It would exonerate the Dum&*%@ flat tire design as the cause, but I’d still rather have some air and rubber.
Is the tire pressure monitoring system a penalty for the public’s outcry over the notorious Ford/Firestone debacle? Of course Americans seem to demand extravagance in lieu of practicality.
What @CapriRacer said. Also nitrogen will make NO difference. These days 55 series is not low profile. The guy getting flats probably had 40 series or lower.
Lower aspect tires can have the same air in them as their high aspect counter parts. Low aspect tires are normally wider and have just as much cushioning in some cases as their narrower high aspect ratio tires. Obviously lower aspect tires then normal with the same width don’t.
Melott said: “…Actually, the load carrying capacity is the product of the air pressure and the surface area in contact. …”
Sorry, but that is incorrect.
First, I am a tire engineer and this is the area of my expertise. Load carrying capacity is determined by a complicated formula that calculates the theoretical load to get a certain amount of deflection in the tire. While the size of the contact patch varies both with inflation pressure and load, the contact patch size is the result of those 2 things (and a few more), and not the other way around.
So a low profile tire and the high profile tire have about the same interior volume for the same load carrying capacity.
And moisture? Sorry, but liquid water permeates through the tire in the form of water vapor. even if water is present in a fresjly mounted tire, it doesn’t take very long for the water to evaporate.
Condensation? I don’t think so. The Law of Partial Pressure of Gases says that the water vapor will stay in the form of water vapor inside a tire. If this were a problem then lots of tire busters would be reporting water in tires when they get dismounted and the switch to dry nitrogen would be in full force. That is just not happening!
Re moisture in tires, compressing air seems to cause a significant amount of moisture to be condensed and accumulate in the tank to be drained.
And although my knowledge of tires is acquired from the dirty side of the equation it does seem that load is largely determined by pressure. Of course the construction and resulting load range determines the pressure capacity of a tire and therefore the load it can carry. I recall some “mobiliner” tires used on mobile homes that were 6.50x14 with load capacities of well over 3,000 pounds at 110psi. Those tires were equivalent to 175x85R14 in size.
Dear Engineer,
Yes, there may be more flex in a higher profile tire. However, the force is the product of pressure times area.
Second, are you saying that the tire is more permeable to water vapor than to air? That’s possible, but I would need to see evidence. Note, absence of water vapor is one of the claims made for the use of nitrogen. What goes out can go in; if you are right it’s useless to try to put dry gas into a tire.
Thirdly, the so-called Law of Partial Pressures tells you how to get a pressure from a combination of gases. When it gets below the “dew point” water is no longer a gas. For air at higher pressure, like in a tire, dew point is raised, and the probability of liquid forming becomes greater.
Have you not seen water spray coming out of an air compressor?