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[Ajumepke]

I don't have my manual easily accessible to me.

I have the M-Sport package wheels and tires.

Had the car for about 3 months now - and today I got a warning light for my front left tire saying i have low pressure.

Drove to a Costco w/ Maintenance section - the tire pressure gauge was showing a 31.2 psi. The max for the tire says 51psi.

I filled it to 40.

What's the standard PSI for front and rear tires?

[White1]

On the back of the door jam for the drivers side there is a sticker with the recommended tire inflation pressures for your car, it has a table with tire sizes and corresponding pressures depending on size. That is a good guideline to follow. The 51 psi is just an "absolute max pressure" that the tire can safely withstand. Remember that as ambient temp changes, so does tire pressure, and if you factor in the heat increase caused by friction as the wheels roll pressure will surely increase. If youre on the highway on a hot day, your tire pressure will go up dramatically due to heat, and friction, and these conditions combined with an initial high tire pressure can lead to blowouts.

[wtzouris]

So little information..... what are you driving, a 135i coupe? what tire size(s)?

Tire pressure should be measured cold, i.e. after not driving for at least 4-6 hours..... Once you drive a few miles, tire pressure goes up as the tire gets warm -- typically 5 psi or more. So your 31.5 psi tire is really 27 psi cold, which is way way too low for any 128i or 135i tire, especially a RFT.

For 17" tires, 33 kpsi (measured cold) Front, 36 kpsi Rear
For 18" tires, 36 kpsi Front, 39 kpsi Rear

William

[oneintheory]

The doorjamb says 39 all around on the 135. Cold.

[Pamlico]

Originally Posted by oneintheory

The doorjamb says 39 all around on the 135. Cold.

Strange. Sticker on my '08 135, sport package says 36 all around.

[Lester]

Here is what it says in the manual: 36/36 is about right for the 135 with standard loads and speeds.

[Luvmybmw]

I run 36 'cold' in all four tires. Seems to work ok with the RE-01Rs

[Luvmybmw]

forgot to say that I run 225 front and 255 rear...

[semaj]

Originally Posted by Lester

Here is what it says in the manual: 36/36 is about right for the 135 with standard loads and speeds.

According to the manual that came with my 2010 135i Coupe and the 2010 manual available online it's 36/39 not 36/36.

Anyone know why the tire pressures have changed? From what I understand the tires themselves did not change nor did the weight and or weight distribution of the car.

[moveswiftly]

on the same topic i'm running bridgestone blizzaks lm-25
on my 135i size 225/40/18 all around
what psi should i run 33/36 ?

[wtzouris]

For the Blizzaks on 18 inch wheels I would run either 33/36 or 36/39, depending on what kind of ride you want (I would go with the higher PSI myself)

As for the door jamb vs. the online manual, I think the 135i has uneven F/R tire pressures, like 33/36, or 36/39, etc. I have never seen 36 all around recommended in any of my literature, but I don't think I looked at the paper book that came with the car. Even with identical 205/50 R17s on every corner the car should be 33/36.

[VMRWheels]

Play around with the tire pressures. Depending on your driving style and weather conditions, PSI will vary +/- 2-3. 38-40 PSI should be something nice to keep the car around.

-Charles@VMRWheels

[cpt97m3]

Originally Posted by semaj

According to the manual that came with my 2010 135i Coupe and the 2010 manual available online it's 36/39 not 36/36.

Anyone know why the tire pressures have changed? From what I understand the tires themselves did not change nor did the weight and or weight distribution of the car.

My '09 135i Couple says 36psi F and 38 psi rear on the door jamb.

[keithbickford]

Originally Posted by semaj

According to the manual that came with my 2010 135i Coupe and the 2010 manual available online it's 36/39 not 36/36.

Anyone know why the tire pressures have changed? From what I understand the tires themselves did not change nor did the weight and or weight distribution of the car.

Here is my thought on this. There is no magic ideal number for all drivers and all situations, and most drivers don't care or know how they should adjust air for their driving situation and style. Most drivers who do care struggle with finding the right pressure. Even racing teams spend considerable amounts of time and money finding the magic pressure, and it changes from hour to hour depending on temperature, humidity, course, etc. Knowing this, it must difficult for BMW to determine the proper pressure for us. To further complicate things, BMW has different pressures "for cars that do not exceed 100mph", and "for cars that exceed 100mph." Notice they do not say how often or how in excess of 100mph. If you're reading this, you probably exceed 100mph from time to time. Yet, they have a tiny little sticker next to the large sticker that shows the high speed pressures. My tire store routinely inflates to the lower pressure. They do not ask me if I might drive over 100mph.

The below came directly from the U.S. owners manuals for respective years and applies to the 135i coupe with 215/40/18 and 245/35/18 tires (Sport package) only, but should cause readers to think of why BMW has evolved.

2008 - 2009: never over 100mph: 36/36, exceed 100mph without luggage: 36/36, exceed 100mph with luggage: 38/42
2010 - 2013: never over 100mph: 36/39, exceed 100mph with or without luggage: 38/42

Why did they change? Experience and consumer feedback.

They haven't changed the tires since the beginning of the 1 series, but they have changed the recommended pressures. We should consider this and follow their updated recommendations for safety, performance, economy, hydroplaning. You may sacrifice some ride comfort, but if that's what you're after, you might consider an Audi or Volvo or Mercedes.

[Dackelone]

OP your best bet to to experiment with different tire pressures. One thing I noticed is even just a few psi will make a huge difference on how your car rides. Especially with RFT's.

Since I live in Germany the roads here are glass smooth and I always drive in the double digits. So I always set my tires for MAX on the door jam label. Normally that's 2.4 bar(front) and 2.8 bar(rear).

What ever pressure you set your tires too... DO NOT FORGET to reset the TPMS system. Its a "dumb" system, so once you get the warning light, simply adding air to the tires will not turn the TPMS warning off. You HAVE TO RESET the TPMS system.

First check your tires for the proper tire pressure.

THEN... with the car stopped(but engine running), hold and reset the TPMS via the turn signal stalk. Then drive off. It should only take a few hundred meters(if that!) of driving before the yellow light goes out. You can also use the iDrive menu to do that same thing.

IF you try resetting the TPMS while driving it will not reset. Ask me how I know that! lol

Good Luck,
Dackel

[keithbickford]

Originally Posted by Dackelone

Since I live in Germany the roads here are glass smooth and I always drive in the double digits.

Dackel, I wish I could say the same about the U.S. People here love to modify to ultra low profile tires, but our roads, especially in the north, truly call for monster truck tires. I trashed the shocks on a new car driving at 120mph on an interstate highway through Arkansas.

[Dackelone]

Originally Posted by keithbickford

Dackel, I wish I could say the same about the U.S. People here love to modify to ultra low profile tires, but our roads, especially in the north, truly call for monster truck tires. I trashed the shocks on a new car driving at 120mph on an interstate highway through Arkansas.

Just to rub it in... a picture of the poor condition of the Italian Autostrada, from last week driving from Geneva/Turin/Verona.

[2tonik]

Buy a tire pressure gauge. Every car owner should have one. Moroso makes a good one that is accurate and easy to use. It's about $45.00.

http://ecx.images-amazon.com/images/I/41zACPZhkTL.jpg

[MightyMouseTech]

Ugh. Gotta love 35 series tires and Ottawa "spring" roads:

[VMRWheels]

Originally Posted by Dackelone

Just to rub it in... a picture of the poor condition of the Italian Autostrada, from last week driving from Geneva/Turin/Verona.

To say that I am jealous of these road conditions is an understatement.

[TheSt|G]

BMW recomended tire pressures in the US are now max load PSI thanks to lawyers.

Originally Posted by Dackelone

Just to rub it in... a picture of the poor condition of the Italian Autostrada, from last week driving from Geneva/Turin/Verona.

It's nice when Germany foots the bill to repave Europe.

Roads were really nice when I was in Italy two weeks ago, and the cops don't care about speeding in the slightest.

[kafou]

For the 18" wheels why the pressure are not the same for the 135 and the 128. Same tires size and wheels but different tires pressure?