How often do you guys need to inflate your tires?

Good point about "one side not sitting in bright sunlight"!
The Volt has realtime tire pressure data on the Driver Information Center screen. My cold pressure on all four corners is 38psi- one day last week before leaving for home I was in the last parking spot to the west with a clear shot to the sun on the passenger side. The driver side tires were in the shade reading 38pis, the passenger side tires had been in the sun for about 2+ hrs.. they both read 41psi.
So yeah, one side exposed to the sun makes a difference.

 

I'm objecting only to the 'age' and 'stamina' excuses, not those other reasons on your list. The other reasons have reasonable validity. But for the vast majority of able bodied adults, 'age' and 'stamina' are either lazy copouts, or the result of poor experience with lousy or failing equipment.

 

You seem defensive about this.

I said a manual pump is fine.-- You want to use one?-- Use one.

Portable compressors in one form or another are awfully popular and IMO very nice and convenient. But if you want to get the old manual pump out? By all means...pump away....I'm not stopping you. They are quieter...well except for the heavy breathing and wheezing depending on your lung capacity. And you don't have to plug them in.

I think they are wonderful.

I'm still using my compressor.

And I have no idea how old you are, but as I rapidly head towards the light at the end of the tunnel I can tell you "age" and "stamina" become a more and more valid excuse for a lot of things...from electric compressors to erectile dysfunction pills. One of the two I use. ....at least so far....

I believe you have made a fantastic choice in not going quietly into that dark night, by deciding to use a manual pump to maintain your tire pressure. I applaud your dedication to the old ways. Under normal circumstance I'd be right there with you, but dang if I haven't already bought the compressor/power station and it's already charged up and ready to go. Guess I'm forced to enjoy the relative convenience of letting a machine pump air into my tires.

 

You sure he wasn't talking about the wife?

 

Tires react to temperature change at the rate of about 1 psi per 10 degrees of air temperature change. A recent good test was leaving Raleigh, NC on the 16th of March, around noon, where the temperature was a super nice 72 degrees. We were heading back home to Maine. We arrived home on the 17th of March, late evening, where the temperature was a slightly cooler 12 degrees.

The next morning when I got into the car and started it to move it to the other side of the driveway, the TPMS warning came on. The ambient air temperature was 1 degree above zero. I shut the car off and decided to check the tires. All of them were down around 23-25 psi.

We started that trip in Raleigh with 32 psi in each "cold" tire, set by the dealership and rechecked by me (yes I carry a tire gauge). So I knew the reason the tires were so far down that morning.

Springtime in Maine brings some pretty wild temperature swings sometimes. Two days ago I went for a bicycle ride and afternoon temperatures topped out in the lower 70s. This morning we had 2 inches of new snow on the ground and the temperature was 21 degrees. Tonight we'll cool into the teens and I'll be snow skiing tomorrow morning. So, if you want to have reasonable tire pressure this time of year, you really have to pay attention.

I try to check tires before the sun gets on them in the morning, and try to shoot for a pressure that won't be too high by the middle of the afternoon. If the temperature in the morning is 20, and expect a high of 65 degrees that day, I'll keep the initial pressure about 4 psi lower than I would normally set. I like to keep the Prius at 38-40 psi front and 36-38 rear, so under those temperature conditions I would set the front tires at 34-36 psi and the rears to 32-34. By the time the outside air temperatures hits 65, my tires will reach that 38-40 front and 36-38 psi rear in the afternoon.

Air temperatures generally range around 20 degrees on a normal day around here. So I try to keep that in mind when inflating my tires.

Checking tires every couple of weeks is a good idea. Once a week is better, especially if the temperatures are changing a lot. Once a month is a little on the infrequent side, but better than nothing.

Another rule of thumb that I've heard more than a few times from "tire guys" is that a tire will lose air at the rate of about 1 psi per month all on it's own. Even if not driven on.

Another great idea: never inflate a tire more than recommended Max on the sidewall.

 

Learned a lot about tire on this thread!

I would like to add one trick, but probably not everyone will agree...

One of tire always leak tiny bit air and need to pump every week. It looks perfect from outside, so I assume it is sand/bubble in rubber. My solution is to put 3 tea spoons of Tire Sealer, mixed with 5 bags of black pepper powder I got from restaurant.

Leaking stopped. Forever!

 

Sounds like an old wives tale, but if it works, Happy Days!

 

I hesitate to ask, but where did you put this concoction of sealer/pepper?

 

Most of the slow leaks are due to an imperfect bead seal to the rim and a little bit of tire sealer often stops that. I really don't think the pepper is necessary and might make the tire changer REALLY mad at you on the next change.

And as for the theory that all tires leak some: Absolutely not true. I've had several cars over the years in which I only had to visit the pressures in the spring and fall due to the temp. changes.

 

They get low for sure. I've been riding my motorcycle again for 6 months, last time I air up, I had them at 40psi.. I noticed last week i could hardly push it back off my porch, so I checked my air pressure, and front and back were down to 12psi.. Can't believe I didn't notice sooner. The bike rose up in the air when I aired them back up.

 

In my case, when I only used sealer, it may last for one month or one week, quite randomly, and then start to leak again. That's why I added pepper powder. If I can find some other none bio powder, I will. But pepper is easily available.

Adding Pepper does not upset the tire guy. The sealer does. One of the guy told me that once use the sealer, you cannot apply patch. I am not sure if that's true, because you can sanding the rubber surface to get to fresh rubber. Obviously cleaning the sealer is not that easy.

Not all tires will leak regularly. But if one of them does, I still think sealer + pepper is a good solution

 

Bikes are somewhat different.
What model do you have that recommends 40 in both ??
How old are the tires ??

If my bike tires lost that much air, I'd be looking for a leak or putting in tubes.......or getting new tires and being sure the rims got cleaned good.

 

Not my experience. Air will eventually leak through rubber.

 

If easy rider said it, it's true
Just want to add, nitrogen usually goes six months without requiring a top up, air requires bimonthly adjustment,jmho,ymmv

 

Absolutely NOT true......unless maybe you are talking about over 30 years or so.
That is a myth that has been created by the "Nitrogen in your tires" people.

Your "experience" does not tell you WHY or where your tires lose their air.
If you are talking about a year or less, I guarantee you that enough molecules do NOT pass through
the rubber to make a measurable difference. They just don't.

 

I run mine at 44 front and 42 rear and I check them every Sunday afternoon.

 

I'm not aware that makes a difference. Maybe one side was in the sun and the other not.

 

Like the original poster, I inflated the tires to 40PSI as an experiment and was very surprised at the MPG jump (being a skeptic figured maybe 1-2 MPG but jumped 14-16MPG depending on driving conditions.) Now when MPG drops I check tire pressures. Learn something new.

 

N2 leaks more slowly. Absolutely TRUE from a chemist's theoretical perspective (and real world tires per Consumer Reports). However, as pointed out by Consumer Reports, since air is 78% N2, the net effect is maybe 30% slower leak rate. You still need to check pressure.

Tires act like membranes thru which O2 and N2 diffuse. N2 is larger molecule and permeates as much as 3-4x slower than O2. That's impressive on the surface but it doesn't amount to too much advantage since air is 78% N2. If you want to say the N2 advantage is over-hyped, OK.

PS- I am not aware of anything that can be practically done by tire makers to prevent the normal permeation of air thru the tire walls. However, for example in gasoline red safety containers, the newer CARB-approved plastic containers are treated to reduce permeation by vapors. But I have not heard of a similar treatment for tires.