Tire Inflation?

[DurhamProPhoto]

I am a little puzzled about something. My Mz5 has a
sticker that says the tires should be inflated to 34PSI.
The tires themselves say that they should be inflated
to 44PSI Max. Which should I be following? My wifes
Mz3 Sport is running the exact same tires and her sticker
says they should be inflated to 32PSI not 44.

Running at 32/34 the car does hug the road better and
the ride is smoother but, If I run the tires at a lower PSI
do I not cause edge wear?
Is there any other reason I would not follow the tire
manufacturers numbers?

Cheers,
Robin

 

[opus]

Robin,
The 44 is the maximum pressure. The number inside of the door jam is the number to follow. The manufacturer picks the tire and then decides what the best psi is for the compromise between ride, handling, mileage, and wear. Wear also varies between over and under inflated tires. Over inflated tires cause excess wear on the middle treads, under inflation causes wear on the outside treads. The door jam is the number to follow.

 

[DurhamProPhoto]

Thanks for the reply Opus. I phoned my dealer
just to confirm and they said it has to do with expansion
and contraction as the tire warms and cools. When the
tire is hot it can reach 44psi the max inflation. So I am
going out now to let some air out of my tires. Personally
I did not like the ride at 44 it felt like riding in a truck.

Cheers,
Robin

 

[Kid Red]

My dealer puts my tires at 32 psi. I inflated them up to 34psi as the door jam says. Not sure why they like 32 over the door's 34 recommendation.

Under 32 you'll notice steering is more difficult and gas milage will suffer the lower the psi.

 

[jandree22]

My dealer puts my tires at 32 psi. I inflated them up to 34psi as the door jam says. Not sure why they like 32 over the door's 34 recommendation.

Under 32 you'll notice steering is more difficult and gas milage will suffer the lower the psi.

Yep. And while some like to inflate them more than recommended for a 'firmer' feel and better fuel economy, this will actually cause the bottom of the tire to round out and you'll get higher than normal wear in the center of your tire.

Always follow the sticker on the door jamb.

 

[jlk_250]

I phoned my dealer
just to confirm and they said it has to do with expansion
and contraction as the tire warms and cools. When the
tire is hot it can reach 44psi the max inflation.

This is not true. The max pressure on the side of the tire is for cold inflation. It can get higher than that due to the internal temperature increasing during use. Here are some links with more info on the subject. http://www.enjoythedrive.com/content/?id=8749 http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=73

I agree with what other people said. Mazda knows best so follow what they recommend.

Jon

 

[Kid Red]

Expanding the topic, anyone filled up with nitrogen yet? Costco is supposed to have it and I'm going to try and remember to fill up with that and see if I notice any differences.

 

[monsta]

Do they do it for free?

Since "regular" air is like 75% Nitrogen, it seems a bit like overkill.

On subject, I always air my tires up 1-2lbs. more than what the door jamb says. A simple way to know if your tires are inflated properly fo rthe weight they will caryy is to drawa thick chalk line across the tread and then slowly drive straight for about 100'. Look at the lines. If it is worn off equally, then you've got the correct amount of air in there. Worn in the center more = too much air. And of course, the opposite holds true.

Not sure how well it works on a 50 series tire. I (used to) use this method on my Excursion when towing or loaded up for a long distance. Now, I just know how much air to add or subtract based on my (gu)estimated weight.

FWIW, the tire will hold more air than 44psi. It's just the tire when aired up at 44psi will holds it's max weight listed on the sidewall. I would imagine that there are times when 44psi would be appropriate depending on the weight carried.

 

[meackerman]

I got tires at Costco for another vehicle. Yes they fill them with nitogen for free. No I couldn't tell the difference.

 

[Zoom5Zoom]

fill up the tires on one side to 75 and run on two tires like on tv lol

ok don't do this unless your a professional

 

[Charlottesmum]

I have had to have all 4 tyres replaced at 10,700 miles (UK) The main cause of the excessive wear was down to the tyres being inflated incorrectly. The information on the door side is at best misleading giving several different pressures.....
The inside edge of the rear tyres wore almost away.
I got my dealer to replace the tyres with new ones, not the horrible Dunlops that were fitted from new, and to do a 4 wheel alignment.
The dealer forked out for 1 1/2 of the new tyres, so I am happy.....

 

[Kid Red]

Do they do it for free?

Since "regular" air is like 75% Nitrogen, it seems a bit like overkill.

This is what I've read/found-

Easy to miss the whole point, Nitrogen will leak less from the tires than normal air due its structure, therefore the theory is the pressure will remain as filled for longer.
The benefits are created by having tires filled at the correct pressure longer, less tire wear, increased fuel consumption, safer ride.
Trouble is there has been no independant research to say exactly what the % savings are, but there are savings!

 

[7red7]

I forget what other forum this was discussed on, but I do remember some really good advice given out that I follow to this day without any problems...

Mazda 5 Tire inflation tips-

1. Get yourself a trusty analog gauge...While all of these so-called 100% accurate digital gauges claim they are never wrong, they are in fact almost never right...Also stay away from the old pencil gauges they are notorious for giving false readings as well...I personally use the one pictured here in this link... www.shamelesscommerce.com/ProductDetails.asp?ProductCode=GAUGE

1. Always check your tires when they are cold...The best time is first thing in the morning...

2. Try filling your tires to 37PSI per tire all around while cold...Once you drive for a couple of miles and they heat up, they will naturally expand by 2-3 inches which will have them running hot at about 40PSI...In extreme heat when temps rise above 100 degrees outside, the tires may expand by up to five pounds...However, this will still have you running two lbs under the max PSI of 44...

Quite a few 5 owners have tried this method for the stock Toyos and it seems to smooth things out, give you better handling response at higher speeds, and as long as your allignment is centered, it won't wear your tires out too early...I've been using this method now since the first month I bought my 5...I have now had two oil changes performed at the dealership and upon each inspection (including tire rotations) all of my tires are showing no signs of wear with well over 10,000 miles on them now...

Best of luck!!!

 

[Kid Red]

37psi!?!? Wow, that sounds very high to me. I fill mine to 34psi and the dealer twice has put all the ties to 32psi as I found out after getting home. Why would you go up to 37psi if it's 34psi recommended? Maybe I'll give it a try if other 5 owners swear success. (btw-, it's 3 tips you listed)

 

[jandree22]

37psi!?!? Wow, that sounds very high to me. I fill mine to 34psi and the dealer twice has put all the ties to 32psi as I found out after getting home. Why would you go up to 37psi if it's 34psi recommended?

(werd)

I wonder if people also put in 91 Octane because it gives 'better performance' even though Mazda says spec is 87. Just a thought... (poke)

 

[was98strat]

(werd)

I wonder if people also put in 91 Octane because it gives 'better performance' even though Mazda says spec is 87. Just a thought... (poke)

I put 91 in last fill, (the station was out of regular, so we got 91 for the price of 87) I didn't notice any appreachabe difference. 91 Is a waste of money If this fill is any indication.

 

[X10James]

Since "regular" air is like 75% Nitrogen, it seems a bit like overkill

78.084% exactly So lets say you get 20% more Nitrogen in a 100% nitrogen fill from completely flat... but, isn't there a little bit of air already in the tire? Do they flush it out, or pump down to a vacuum first? I wouldn't care if they did it for free, but you'll never catch me paying for such a thing.

Seems silly, 20% of the gasses in my tire could potentially leak a little faster than the 80% that is nitrogen... I'll just check them and top them off every few months as necessary.