Tire care basic questions

i never paid attention to my tires on any of my several cars before. The Prius i just got needed a new set of tires so i got some that got good reviews on these forums. I thought that would be the end of it, but when i checked the pressure in the tires, every tire was different, and my understanding is that it's good to keep the front ones the same and the back ones the same, so things are in balance. And the front ones should be a little higher.

I put air in the tires. When i checked them the next day, they were lower, two or three or more pounds lower.

I've been checking them cold, and putting air in after only a short drive of a few blocks to the gas station. Would that make a difference of many pounds?

How much air is it normal for tires to lose in a day?
In a week? In a month?

I have gotten tired of going to dark deserted gas stations to put more air in my tires every night so i want to get a tire inflator/compressor.

Today i got a sears Craftsman one that plugs into the car's power outlet. I haven't taken it out of the box yet. I really wanted one that plugs into the AC in the garage but i couldn't find one at Sears, PepBoys, OSH, or Kragen. They have a couple on Amazon, a Black and Decker and a Bion-aire, which i may order. I wanted to ask forum members about this.

Will it harm my battery in my Prius to use one of these air compressors that plugs into the car 12V outlet? Does it drain the battery?

Do forum members have any recommendations for what type of air compressor/inflator to get?

I got so burnt out on going to the gas station for air every day that i stopped doing it, and i'm just letting my tires be whatever pressure they are, until i have a way of inflating them at home. Today, the front tires were 35 psi and the back tires were 37 psi, even though when i put air in the last time, i had put 41 in the front and 39 in the back. Now, the front is lower.

 

Timberwolf--At first i was using a $6 digital gauge i bought at the Toyota dealer. It was very hard to use because it did not easily make seal around the valve, so lots of air squirted out while i tried and tried to get it to measure the pressure. Being ineperienced, i thought this was my problem, that i was just unskilled at doing this, and hoping i would get better at it, but i didn't. After i lost it, i got an Accutire digital gauge that is very easy to read and see in the dark, and it forms a perfect seal around the valve every time, it's almost impossible to do it wrong. I also got a gauge that's a chuck on the end of a short hose (6 inches?) with a round dial on the other end, and it too was much easier to take a reading with than that first one i had. Now i know, not all gauges are created equal. So i'm not sure how that effected my first few days of recording the pressure, the irregularity of the readings, and the leaking of air, maybe most of it was because of the gauge making the air squirt out so much.

I took repeated readings, to make sure they were right, and sometimes they were the same and some times they weren't.

I mostly checked it when the tires were cold, in the morning or after it had been parked for hours. Sometimes i checked it after driving. The first time i put air in, i had driven probably about a mile, trying to find a gas station that didn't have a line of cars to wait for the air, or that had one that was working. So, when i put 41 in the front and 39 in the back, i now have learned that when cold, this would be a couple of pounds or so less, so if it was less later when i checked it again, this would be why it was lower, not that air was leaking.

One thing that set me off taking these measurements and fretting about it is that someone on the forums pointed out to me that the sensors are on the valves so when the installer replaced the valves, my tpms might've been damaged, resulting in tires leaking air (another thread had a couple of reports of that happening)--so this had me very worried that I should've gotten my tires at Toyota instead of Discount Tires, especially after i measured them and the air was way less than what the installer said he put in (37 lbs) and then what i put in, 41/39.

a little knowledge can be a dangerous thing.


tires, tyres, trunk, boot, windshield, windscreen, gas, petrol, tomato, tomahto, all good. Thanks for the suggestions and experience.

 

Thanks!

I read somewhere on these forums that some tire pluggers could cause problems for the tire pressure sensors--but someone else said you just have to clean them off. Are there different kinds of tire pluggers, other than the kind where you spray stuff inside your tire?

 

I got one today. here it is on Amazon--

http://www.amazon.com/dp/product/B000IE0YIQ?tag=priuschatcom-20 got it for $31 at Lowe's.

Does 120V mean the kind where you need a 3 pronged outlet? It's both AC and DC. I am waiting for my tires to cool off and then i'm going to go put air in them, the front were down to 34 and 33 before i left for Lowe's, the back were 36, which is either the same as yesterday, or one pound less. And the front ones are about like yesterday too, maybe a pound less. I hope i have an extension cord long enough, the cord on the inflator is short, the outlet is in the roof of the garage, i need to use a ladder.

Once i have air at home and a good gauge, i will have a better idea of whether the tires are losing air or not. If they are, i'll have them remounted or whatever needs to be done. I do have a good gauge now, so i just need to get an air pump that works.

 

yesterday i got a compact digital 12V pump at Sears, it was the only one out of several that had overall positive reviews, about 75% positive. The others were more like 25% positive.

This one:

Craftsman 12 volt Air Compressor/Inflator with Digital Tire Pressure Gauge - Model 75114 at Sears.com

I was thinking I'd keep that one in the car, and keep the 120v AC one i got in the garage, even though the 120v one also has a 12v capability and cable. But it's not as small, and storage in the car is at a premium. Anyway, i just want to keep the 120v one in the garage, ready to use.

In reading the user reviews for these pumps, i saw that some people reported a problem with the 12v pumps causing blown fuses in some cars. Is this a risk?