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Old 03-15-2009, 05:37 PM   #1
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Tire pressure.

All my tires are P195/65R15s. 3 of them print a max pressure of 44 psi. The lone standout is one in the driver's side rear that reads:max press 35 psi. Is that a bad combination? Is it simply a different type of tire and as long as the dimensions are consistent, I shouldn't worry about it?
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Old 03-15-2009, 05:46 PM   #2
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Re: Tire pressure.

Don't worry about it. Inflate them all to the recommended inflation (not the max) and drive it.
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Old 03-15-2009, 06:06 PM   #3
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Re: Tire pressure.

You always inflate the tire to the vehicle manufacturers recommendation which will be less that the max on the tire, usually.

If there is any question whether or not this is the correct way to inflate the tires look on any tire manufacturers web site and they will say the same thing.

Overinflating can cause excessive stress on the tire, Less traction, and more braking distance. Not to mention a ruff ride and the premature wearing of tire tread, typically the center tread.
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Old 03-15-2009, 08:38 PM   #4
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Re: Tire pressure.

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Originally Posted by sailor86 View Post
All my tires are P195/65R15s. 3 of them print a max pressure of 44 psi. The lone standout is one in the driver's side rear that reads:max press 35 psi. Is that a bad combination? Is it simply a different type of tire and as long as the dimensions are consistent, I shouldn't worry about it?

Is it the same brand and model of tyre?
If so I wouldn't worry about it, just make sure it is inflated to manufactors specs (usually around 30-36psi for a tyre that size).

If it is a different brand and model of tyre, then beaware that it will have different levels of grip and response to the tyre on the other side at the back.
This is an illegal combination here in NZ, and if you try some hard breaking and swerving manuvers (like trying to avoide a hazard, e.g. a child or another car) you will find out why very quickly, as it becomes very easy to lose control of the car.
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Old 03-15-2009, 10:28 PM   #5
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Re: Tire pressure.

I wish it was illegal in MN! There are many cars on the road with 4 different tires on them! I would bet that half of those have steel cords showing in at least one of the tires, half of those have worn out front end parts, and half of those have brake issues.
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Old 03-16-2009, 05:19 AM   #6
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Re: Tire pressure.

So where do I find mftr's recommended inflation pressure? Do I do a ballpark figure as in: 44psi translates into 40? The rear driver side is a Uniroyal Tiger Paw. The rear passenger side is a Douglas Xtra Trac A/W. No two tires match on my car.
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Old 03-16-2009, 06:54 AM   #7
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Re: Tire pressure.

Quote:
Originally Posted by sailor86 View Post
So where do I find mftr's recommended inflation pressure? Do I do a ballpark figure as in: 44psi translates into 40? The rear driver side is a Uniroyal Tiger Paw. The rear passenger side is a Douglas Xtra Trac A/W. No two tires match on my car.
The location varies somewhat by manufacturer. Some will put the recommended cold inflation numbers for front and rear on the VIN tag in the driver's door jamb, some will have a separate sticker on in the rear passengers door jamb (4-door) and I've seen other's that will have a sticker inside the fuel fill door. Most will likely also have the information in the owner's manual as well, or at least the manual will guide you to where to find the information.

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Old 03-16-2009, 07:34 AM   #8
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Re: Tire pressure.

That's all well and fine, but I've got 3 tires that read max inflation 44psi, and 1 that reads 35psi.
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Old 03-16-2009, 08:28 AM   #9
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Re: Tire pressure.

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That's all well and fine, but I've got 3 tires that read max inflation 44psi, and 1 that reads 35psi.
It doesn't matter what the tires say. Inflate them to what the vehicle says. The only time it would matter is if the vehicle manufacturer recommended an inflation that exceeded the tire manufacturers maximum inflation. this would be a pretty good sign you have the wrong tires installed on the vehicle.
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Old 03-16-2009, 12:34 PM   #10
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Re: Tire pressure.

Right, the sidewall inflation is a "Maximum" inflation number, what the tire can handle, but not what the car's manufacturer recommends. You should never inflate based on what's on the sidewall, it should always be what the "door sticker" suggests based on your load. That's true for all modern cars, and a common misunderstanding.

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Old 03-16-2009, 01:00 PM   #11
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Re: Tire pressure.

as i am alignment man you need to go with what it sais on your door or manual don't go with what it sais on tire. you'll get better gas mls. if you do this.
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Old 03-16-2009, 01:17 PM   #12
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Re: Tire pressure.

Correct. It doesn't matter if you put 4 E-range truck tires on that car. Even if the sidewall says 80 psi max, it only takes about 30-35 psi to suspend the weight of your car. The pressure listed on the sticker (or owner's manual) of your car is the right inflation pressure. Those tires are designed to be installed on a few thousand different cars of different weights, but your car is what determines proper pressure, not the tire.
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Old 03-16-2009, 01:19 PM   #13
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Thumbs up Re: Tire pressure.

Never knew.
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Old 03-16-2009, 10:49 PM   #14
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Re: Tire pressure.

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Originally Posted by sailor86 View Post
The rear driver side is a Uniroyal Tiger Paw. The rear passenger side is a Douglas Xtra Trac A/W. No two tires match on my car.


Do yourself, and other road users a favour, and get 4 tyres the same.
Even if you have to get 4 second hand ones, the car will be a thousand times safer.
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Old 03-16-2009, 11:06 PM   #15
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Re: Tire pressure.

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Do yourself, and other road users a favour, and get 4 tyres the same.
Even if you have to get 4 second hand ones, the car will be a thousand times safer.
I'm not sure if its a tire difference, or if its just social perception. Using different tires here is not taboo at all. Its not ideal, but the amount of difference that having different tires could cause is so tiny. 99% of the drivers out there wouldn't know what to do except panic if they were in any hazardous situation, and the 2% increase in predictability you gain from having 4 tires the same is really not a big deal here. No state in the US requires 4 matching tires. In fact many cars specifically are shipped from the manufacturer with different tires.

If you think about it, a Corvette comes with 245mm tires on 17" wheels up front and 315mm tires on 18" rims in the back. That's a lot more difference than just a different brand of the same size.

Not disagreeing with you Moppie... just curious as to the different perceptions on different continents.
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