Maximum tire pressure. Who to believe?

passat
wagon
volkswagen

#1

On the door frame of our 2004 Passat Wagon the recommended tire pressure is 35 psi for the front and 44 psi for the rear. That recommended rear pressure is also the maximum recommended for the (Michelin) tires that we have on the car. It was also the maximum for the original Continental tires. Recent discussants on the board say that that you should never inflate to the maximum, but VW is recommending it. Who do I believe?


#2

It may be a little confusing, but they meant never EXCEED the maximum.


#3

How close to maximum rated psi is their recomendation to the o.e. continentals ? It’s probably too late to know. That would guide you to know if the current michelins are actually too light.
Air to the car’s specs.
Within tire’s specs you’re ok.


#4

Always go with the doorjam pressure (or wherever the manufacturer’s recommendation is).

It’s perfectly safe to inflate the tires to the maximum, but it’s not a good idea to ALWAYS do so regardless of what the manufacturer’s specifications are, as some people do.


#5

Do not go over what is on tire.You may have a real good tire that says 50psi or a cheap tire that says 35psi. Now this is not a good gauge to tell how good a tire is but I think you get what I mean.


#6

You must be a mechanic or something - word has it no one understands what the information printed on a tire’s sidewall means.

Follow the door frame and check the pressure regularly (morning while cold) - as you should anyway. Do this especially when the weather gets warmer.


#7

You can safely inflate to the maximum, but you can’t exceed it.

Are you sure the 44 psi rear tire pressure is for normal conditions? I can understand this if the vehicle is loaded to its capacity, but not for normal, every day driving with no heavy loads.

I’ve never come across a standard passenger vehicle that had a normal tire inflation pressure that high. There are many tires that cannot safely be inflated to 44 psi.


#8

You can inflate to the maximum pressure. That’s what it’s for, after all.


#9

No matter whats on the door do not go over what is on tire.


#10

Usually it gets said to go with the pressure on the door or door frame. You wouldn’t just fill the tires up to the maximum that’s writen on the tire without looking at the car maker’s recommended pressure.

If you aren’t carrying a load in the back, you might try putting less pressure in the rear, but that would be up to you. If it were mine I would like to go with 37 in the rear. I think you have plenty of leeway, whatever you choose.


#11

This isn’t that hard or complicated.

Max tire pressure is given on the sidewall of the tire, and it is specific for the tire NOT the automobile.

The recommended pressure is listed in the owner’s manual, on the door frame, and sometimes inside the fuel filler door on the vehicle.

Most cars have a tire pressure recommendation for normal loading and another for when the vehicle is loaded to the max of it limit. So when you are loaded up taking Jr to college you need more pressure in the rear tires to carry the extra weight of the full load. When the car is not loaded the front and rear tires are often inflated to the same pressure.

In the case of your Passat my guess (don’t own one and can’t read the owner’s manual) is that normal pressures are 35 psi front and rear, and 44 psi for the rear when the car is fully loaded.


#12

Thanks for all the different takes on the subject. In answer to one question, yes, the door frame pressures do not specify whether the vehicle if fully loaded or not. Just the one option for the pressures. I always ran the Continentals at 44 in back, but have opted to go to 42 with the new Michelins. It seems high to me as well, compared with the other cars I have (all of which do fine at about 32 psi), but I’ve never pretended to understand the logic behind many things on the Passat. Thanks for the advice.


#13

Follow the recommendation in your owners manual or the placard on your vehicle. The max pressure listing on the tire is for that tire and not your vehicle. The tire could be used on hundreds of different vehicles.


#14

The car manufacturer has done test track testing of those tyres to develop the best (safest) pressure for your car and the OEM tyre size. You should go with what the manufacturer recommends.

So far no one has noted that if the tyre size changes, then the pressure recommended by the car manufacturer no longer applies. In that situation, I would suggest sticking close to the OEM recommendation.

What is it that prevents people from reading that word MAXIMUM

1 a : the greatest quantity or value attainable or attained b : the period of highest, greatest, or utmost development
2 : an upper limit allowed (as by a legal authority) or allowable (as by the circumstances of a particular case)
3 : the largest of a set of numbers; specifically : the largest value assumed by a real-valued continuous function defined on a closed interval


#15

Perhaps I can help here.

VW, like many German vehicle manufacturers, used to specify 2 different condition / inflation pressure combinations: Normal (which I think meant one passenger) and Severe (which I think meant fully loaded and high speed).

This confused a lot of people since it 1) implied something in between for situations where there was more than one person in the car and 2) it seemed to imply that unless the vehicle was fully loaded and driven at high speed, the inflation pressure should be at the lower value - and that’s clearly wrong.

I don’t know this for a fact, but I suspect they changed to one pressure for simplicity and I also suspect they only did this for US vehicles.


#16

"VW, like many German vehicle manufacturers, used to specify 2 different condition / inflation pressure combinations: Normal (which I think meant one passenger) and Severe (which I think meant fully loaded and high speed). "

My 2002 VW list two conditions based on load.


#17

First, you are wrong about the original tires. They were H speed rated tires and H speed rated tires will ALWAYS have a maximum pressure of at least 44 psi. It’s part of what comes with the speed rating.

You have obviously put on tires that have an S or a T speed rating.

Long story, short version: It’s OK to use 44 psi in S and T speed rated tires in spite of what the sidewall says.


#18

I’m surprised to see this thread resurrected after 3 months. I appreciate the additional insights, but I need to reiterate that my original post was about the posted recommendations on the Passat’s doorframe. The attached photo should remove any doubt about this being tied to specific driving conditions. It’s simply a flat recommendation for 35 in front and 44 in the rear, regardless. Capri, my original post said nothing about tire sidewall information, but both the original Continental and the present Michelin tires are H rated. No S or T.


#19

Wow, that’s what my friends in Baltimore would call a noitmare! You can’t have 5 fat people in this vehicle? What good is it? Have you considered the possibility of a misprint?

Why did you buy a car with such a limited capacity?


#20

There are three issues involved.

  1. Maximum pressure: The tyres have a maximum pressure that they can be safely handle. You want to use. In this case you seem to be suggesting you want to use it at the max listed on the tyre, so as far as the tyres go, that should be fine.

  2. Ride comfort: You seem to accept the harsher ride and since you are the only judge of that, then that should also be OK.

  3. Safety: This is the one that I can’t offer a yes or no answer. While all the authorities (see below) agree that the pressure listed in the owner’s manual is the recommended proper pressure by all authorities, it must be acknowledged that there likely is some amount of flexibility.

Car manufacturers are concerned with many things. They want people to be happy with their cars and that means they want the car to give good mileage and the want the car to ride comfortably.

I have yet to see anyone who has access to real test track facilities and actual test results on modern cars and tyres, offer objective data to support the idea that pressures higher than that recommended by the manufacturer are as safe as the recommended pressure.

My opinion is that a few psi over the recommended value is not likely to compromise safety by any material amount. I would also suggest that there is a point where higher pressure will reduce safety enough to make a difference.

If mileage is more important than safety, go ahead and keep upping that PSI. Other wise, I would suggest reading the following and going along with the professionals. If it really was safe to go higher, then I don’t think all the authorities are going out of their way to tell us to use what the car manufacturer recommends.

http://www.tiresafety.com/
This is sponsored by a tyre manufacturer Bridgstone - Firestone and instructs the reader to check the owner’s manual for the correct tyre pressure.

Here is another from the Goodyear site.

Tire Inflation
Proper tire inflation is a key ingredient in driving safety and long tire life. It is wise to check your tire’s inflation at least once a month with an accurate tire pressure gauge. Continuous loss of inflation pressure is an indication of a possible tire/wheel assembly problem; consult your tire professional immediately if you encounter this situation. Be sure to check the pressure while the tires are cold, and have not been used recently. If you drive even a mile this will cause your tire pressure to increase and give you an inaccurate reading.

Check Your Air Pressure
Keep your tires properly inflated and you could improve gas mileage by more than $1.50 every time you fill your tank. The recommended tire pressure for your vehicle is located on a sticker inside your driver-side door or noted in your owner’s manual.
You might also try the US Department of transportation.
http://www.nhtsa.gov/cars/problems/E...intenances.htm
They say:
You can find the correct tire pressure for your tow vehicle in the owner?s manual or on the tire information placard.