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I got tires at Discount tires. The brand is Arizonian Rocky Mountain: http://www.arizoniantires.com/arizonianRockyMountain.html
Anyway, this is for a Toyota corolla. I asked how much air they put in it and they said
35, that it is actually for 32 and that "you can't get anymore air in it". This seems a tad dubious-- as I doubt you would ever put the maximum amt of air you could get in a tire, even if you were hypermiling on the severe end-- wouldn't there be some place left-- doesn't air expand with heat. Or do I have my physics backwards? (BTW, it was quite warm-- maybe 88 degrees today, so I know that has something to do with it.)

But anyway, I suppose they can say this all to me-- what they hey I'm a gal. You can say all these things and what do I know? So the thing is what DO I know? Not much. But I didn't pursue it.

What do you all think of this?
And if the tire is supposedly rated for 32 psi. Is 35 ok for my purposes. Would this help me on the mpg?

Thanks.

--des

You are right in thinking that physically you can put more air in the tire. Not sure what the cold rating on the tires are, but you can find that out on the side of you tire. You are also right in that even the most advanced hypermilers don't pump their tires up even close to the bursting point.

What ever the tire says is the max is definitely safe. Look at the tire and let us know what it says under max cold psi or something like that.

And yes, air expands in the head and contracts in the cold. I think the rule of thumb is 1psi per 10F. So if you fill your tires up to 35 at 80F if you live in a colder climate where it reaches 0 then your tire will be 27psi which is dangerously low. So keep an eye on the pressure as it will fluctuate with temperature. It is always better to have too much air than too little.

Check on the side of the tire for the max psi. It is probably around 44psi. If they said 35 is max, that is what the manufacturer recommends for comfort.
Did they put the proper size tire on your car? 175/65/14 Discount Tire website did not show that size available in that brand.

You should beable to run it at max side wall. Cheap tires I wont run above max side wall.

Thanks for your responses.

Yes, yes, I thought that was the "just the dumb gal answer" they gave me.

I sure hope they have the right tire size on my car!! If they didn't not exactly sure what I would do about it. The no. is something like 185, didn't quite catch the rest. Max psi *is* 35, at least that's what it looks like. There is also warning on the tire re: overinflating and overloading (the latter isn't at all likely).

I definitely live in a hot climate (well it is usually anyway). It was 88 degrees yesterday, which is typical this time of year.

These are definitely cheap tires, the bottom of the line. :-}
It seems a bit crazy to run expensive tires on a 100 K car. Wouldn't that be like putting retreads on a BMW?

--des

You're perfectly safe running the max psi stated on the sidewall, which as was mentioned above is probably 44 psi for your tires.

You car's door jamb has a much lower number on it, usually in the 30-35 range. I'm guessing that's where you saw the 35 psi "max". That's the number recommend by the automaker for ride comfort, and has nothing to do with safety. Air up with confidence! Pay attention to your car's handling when you do this. Toyotas tend to lean towards a soft ride at the expense of handling, and you may notice (as I did) that your car actually handles better with more air in the tires.

By the way, although I wouldn't put really expensive tires on an "older" car, and it's your car and you can do what you want with it, I personally have found it worthwhile to go a couple steps above the cheapest tires. Tires are the only part of your car that touch the ground, and they make a big difference in your car's performance. Any tire has to trade off tread life vs. grip, noise and rolling resistance. All else being equal, improving one of those variables causes a degradation of the other. But better tires will be made with higher quality construction and rubber compounds, allowing you to improve each characteristic without hurting the others. Mid quality tires typically have much better grip, especially in adverse conditions, than cheapo tires (and are therefore safer), often last much longer (thus saving you money in the long run) and may be quieter and provide more fuel economy too. The manufacturer may also use more accurate quality control, making it less like you you'll get a bad or slightly out of spec tire. My car has 150K miles on it and is only worth $2k, but I personally would not hesitate to spend $300-400 on a new set of tires for it.

Hi there Des!

When you look at the tire, you should look for something like "max. sidewall PSI/pressure: ##"

That will be the defining pressure that you should fill your tires to. If in fact it is 35 PSI, then take them up to 35 PSI. A few over will not hurt as well - my tires are rated at 44 PSI, but I have mine at 46-47. And I'm in hot-hot FL. :)

No sense in putting expensive tires on an older vehicle - those will do ya just fine.

Well, I think that having good tires is important on any vehicle, new or old. That said, you're way better off now that you have four matched, new tires of any brand vs. a bunch of different used tires. My snow tires (when I needed them) were rated at 35psi max cold pressure but I ran them upwards of 40 without issue. If you just want to go with 35 to be safe then that's fine. More would cut down on rolling resistance but it won't make or break you.

I didn't see the 35 on the door jam but on the tire, though I couldn't see it all that well. I'll look at them outside.

I was guessing that a cheaper tire would be lower in no. of miles, noise and the like, but I am not all so concerned about that. I was running with used unmatched tires that just about anything would be better than that. I'm not saying some of you are wrong here-- just my feelings. :-)

The tires have a 30,000 mile life. If I keep the car for 1-3 more years then that is probably the life of those tires, and about right. I'm not going to get anything for the car (to speak of) anyway. The car is not going to be "excellent" in a trade anyway.

--des

Some people here with a max 44psi bring theres up to 55psi and they don't seem to have any problems. My tires are 44psi max, but I only have it up to 40psi. I was hesitant to do it during the summer since it was hitting 117F, and I was afraid of the heat expanding the tires. But I think I'm ready to go higher.

I have 65 psi in my Goodyear Integrity's that are rated for 44 psi max. It has been over 90F several times and I haven't had any problems and the car/tires have just over 4500 miles on them.

Desdemona, I've got what I would call lower end tires on my car -- they are only rated for 40K mi. To give you some idea, the current set is identical to the set the car shipped with. I was told that most people only got 20K out of the tires. Want to know what I got? 60K. And I still had enough tred left I probably could have legally gone another 10K or so on them.

I've got 30K on this set and there really isn't much wear at all on them. The max sidewall is 44psi and for most of the life of the last set I ran them at 38psi. The manufacturer recommends 32psi for comfort. I've now got the current set up to 55psi and I've not had any issues with the 90+F days we've been having here in MN. I fully expect the tires to last until after I get another car in a year or so. (At least I hope I can afford another car at that time!!!!)

With your current set I'd say 35psi is definitely safe, and probably mid-40's are okay as well (though I can't of course recommend that to you).

Do check the sidewalls to make sure there are no creases or bulges evident in them. My last car was equipped with a very cheap set that had both of those features when I bought it. Eventually one of those bulges ripped around the circumference and I had a blowout. Fortunately the car had been parked for the previous 1.5 hours so the only thing needing replacement was the tire itself!

Hope that helps.

Do what you feel comfortable doing. It's not worth it if you worry. Wayne recommended to increase the psi about 2 lbs every couple of days up to 44 psi. If you read the tire data, the max psi rating is for that tire at a maximum load rating which is usually a LOT more than what the car weighs.
If you only have 35 in them and you go to 40, you will feel a great difference in how your car rolls.

I have had 60 psi in my Insight tires for over 90,000 miles. The temps this week here in Illinois have been around 95.

Oh I meant to look outside where I might actually see the darn things. I have looked at them and they look good with no bulges, etc.

I'll make a decision based on that.


--des

According to the discount tire website, your car's oem size is 175/65/14. If they put 185/65-14 on, your speedometer reading is 2.2% slow. When it reads 60 you are actually going 61.3. You need to factor in +2.2% to your miles to figure your mileage. You are getting better mileage than you think.

I did understand what you said, but I don't think I'll be adding or subtracting percentages anytime soon. It's like I say, "you do the math". Except usually I mean it.

BTW, they really are rated for 35 psi. I found it on the tire outside where I could really see it. There was also, next to it a load rating. Though I paid no attention to it, as I don't haul things.
Though it could have said something different, but it could only have been 55 or 35 and I am guessing 55 would be unlikely. They feel a little different to me than the old tires. I think I tried to keep them at what would be low here--32 psi. I might try inflating them a tad more. But I'm going to get used to the 35 first.


--des


According to the discount tire website, your car's oem size is 175/65/14. If they put 185/65-14 on, your speedometer reading is 2.2% slow. When it reads 60 you are actually going 61.3. You need to factor in +2.2% to your miles to figure your mileage. You are getting better mileage than you think.

load rating is the weight of the car and what is is carrying I believe. As PSI goes down the amount of weight the tire can carry goes down. I think the load rating means, at max sidewall pressure, the load it can carry is xxxx lbs.

So if you go on a trip and put a lot of people and luggage in you want to not exceed that rating. You wont, because it is usualy pretty high.

Definitely get used to 35psi first. Going higher might help, but the higher you go the less difference it makes. Thats why you see even those pushing hardest for mileage don't go much past 60 (with tires rated like 45 or something.) There isn't much to gain at that point. So increase it, check your mileage and keep increasing it to as much as you can stand, and keep track of your mileage. When the mileage benefit outweighs the comfort level you want then stop.

.....

BTW, they really are rated for 35 psi. I found it on the tire outside where I could really see it.

.....

--des

That's the same as for the cheap tires we put on our Saturn.

I always found it interesting that automakers put 32ish PSI tire specs in the manual, but then provided 60 PSI spares. The automakers don't exactly seem to believe their own specs...

the spare is smaller so it needs more air ;) kind of like bicycle tires needing 100psi ;) smaller surface area means more pressure needed to push against it.

Some people here with a max 44psi bring theres up to 55psi and they don't seem to have any problems. My tires are 44psi max, but I only have it up to 40psi. I was hesitant to do it during the summer since it was hitting 117F, and I was afraid of the heat expanding the tires. But I think I'm ready to go higher.


They will be fine. I put 60 psi in the Civic's oem Dunlops the day we brought it home from the dealership. Over 3000 miles and no problems.

I've never heard of a small passenger car tire having a max psi of only 35. Sorry to have to say this but it's probably because they're cheap tires. I wouldn't push them past 35 psi either.

After years of underinflated tires (no doubt) and that sort of thing, I am getting used to 35 which seems different. I never inflated above 32 before. I think I'll do ok with hypermiling, as the figures I have now on my driving are probably based on usually underinflated tires. I'm changing that behavior.

BTW, I think am going to need to have someone else do inflate them. I did something to my back a couple years ago. So maybe it's just as well. I don't think some car guy would want to overinflate.

--des

I've never heard of a small passenger car tire having a max psi of only 35. Sorry to have to say this but it's probably because they're cheap tires. I wouldn't push them past 35 psi either.

After years of underinflated tires (no doubt) and that sort of thing, I am getting used to 35 which seems different. I never inflated above 32 before. I think I'll do ok with hypermiling, as the figures I have now on my driving are probably based on usually underinflated tires. I'm changing that behavior.

BTW, I think am going to need to have someone else do inflate them. I did something to my back a couple years ago. So maybe it's just as well. I don't think some car guy would want to overinflate.

--des

I'm also sure you'll do fine. :)

You might want to look into a small compressor that runs off of the cigarette lighter socket -- they are not that expensive and though they are noisy, they are much easier on your back than the bicycle pump I use. ;) I'm a little paranoid so I do recommend that you keep SOMETHING in your trunk that can inflate a tire. The last time I needed my spare it was flat so I was really glad I had a pump!!

Good idea. Lately I have been going to a couple known places that have done work for me and ask them to check my tires.


--des

I'm also sure you'll do fine. :)

You might want to look into a small compressor that runs off of the cigarette lighter socket -- they are not that expensive and though they are noisy, they are much easier on your back than the bicycle pump I use. ;) I'm a little paranoid so I do recommend that you keep SOMETHING in your trunk that can inflate a tire. The last time I needed my spare it was flat so I was really glad I had a pump!!

I will say that I run my tires on my 04 HCH @ 38 psi. have had no trouble except for the time I ran over some steel in the freeway and had the left front tire blow out. Then again there were 3 other vehicles that hit it and all of them had blow outs too. Now I drive mostly freeway and country roads very little stop and go but I have 85,000 miles on my car and the original tires still look GREAT. I can't believe how little wear they have. kevin

It may have a max weight rating @ psi instead, which is 51 psi for my tires, instead. Most tires also have another warning not to exceed XX psi to seat bead, you can ignore that one unless you're trying to mount the tire =)