Pressure (cold tire)

Haven't checked the air pressure on my D in some time, so tonight, went into my unheated garage (38 F) with my compressor and air gauge in-hand to determine if she needed air.

To my surprise, the fronts had 32 psi and the rears had 34 psi......

Lesson-learned: Check pressure on cold tires once a month and fill to 38 psi front and 41 psi rear

Strange that your car did not prompt you. Mine seems to do it for the slightest drop in pressure and it is actually rather annoying.

Mine never indicates low pressure, I do keep it rather high, 41-42psi, but only check it perhaps once every two months or so. We don't have any extreme temp changes.

I much rather have the actual tire pressure reading than just a summary alarm though, like my Chevy Tahoe.

Car never prompted me, but the tire pressure was "equal" but low in all the tires. Doesn't the BMW system warn you based on the rotation of differences of the tires, versus the pressure in individual tires? I'll have to take a look at the manual today......

Originally Posted by johntube

Car never prompted me, but the tire pressure was "equal" but low in all the tires. Doesn't the BMW system warn you based on the rotation of differences of the tires, versus the pressure in individual tires? I'll have to take a look at the manual today......

I have had mine warn me for all tires before. Whether they were equally low or not is debatable.

I too wish the system alerted the actual or estimated pressures. I honestly ignore the system after our first winter with massive temp changes that kept setting the warning off. I am glad that after the software update I got that the system now at least tells me which tires are low. Before it just told me that a tire was low and was up to me to figure out which one or even if it was multiple ones.

Originally Posted by johntube

Lesson-learned: Check pressure on cold tires once a month and fill to 38 psi front and 41 psi rear

now reset TPMS. Alarm depends on what it has in its memory. Last time when you did a reset if all tires had low pressure then it will consider it as safe. Also I think you see warning when pressure is 15-20% lower of reset pressure.

Originally Posted by Flyingman

Mine never indicates low pressure, I do keep it rather high, 41-42psi, but only check it perhaps once every two months or so. We don't have any extreme temp changes.

I much rather have the actual tire pressure reading than just a summary alarm though, like my Chevy Tahoe.

That 42-42 psi is high. I run 36-38 psi front and rear. That pressure got me almost 40k miles out of the tires on my 08 335i.

I just investigated this. As per goverment regulations TPMS alerts when you lose more than 25% of the pressure it was last reset at. Given that it transmits to the car pressure information in .1 PSI increments as well as temperature, it would be nice if the actual pressure was displayed (could be done with a simple no cost software change).

Of course for those of us with real winters, pressure will go down with decreasing temperatures. I have non sport and am currently running 34 fronts 38 rears. Overall I like the non sports ride (and smaller - less prone to damage wheels), but would have liked stiffer shocks. That little extra bounce, especially from the rear over bumps is a bit annoying.

A bit early to tell for sure but looks like the rear tires are wearing 2X faster than the fronts. But with the torque of the d, not surprising.

My father n law runs nitrogen in his tires to try and avoid these pressure losses with outside temp changes. He claims it really works, I still am hesitant in his findings. I'd happily switch my BMW to nitrogen though if it in fact really does work just to avoid the TPMS alerts.

Inside door jam on my 2011 335d M-sport says 35 lb. front, 42 lb. rear.

2011 335d with sport pkg: Inside my door jam say: 42 lb. front & 51 lb rear if going over 100 mph. I usually keep it 10% off the "max". 51lb is ridiculously high but I'm assuming it's because of our massive torque on that rear tire.

Originally Posted by Scooner8

2011 335d with sport pkg: Inside my door jam say: 42 lb. front & 51 lb rear if going over 100 mph. I usually keep it 10% off the "max". 51lb is ridiculously high but I'm assuming it's because of our massive torque on that rear tire.

Think the over 100 MPH tire pressures is determined by lawyers. They want to make sure we do not have a tire failure at high speed. Once your rolling at 100 MPH+ torque really has nothing to do with it.

Originally Posted by Snipe656

My father n law runs nitrogen in his tires to try and avoid these pressure losses with outside temp changes. He claims it really works, I still am hesitant in his findings. I'd happily switch my BMW to nitrogen though if it in fact really does work just to avoid the TPMS alerts.

Nitrogen as per Boyles Law!

I'm not going to pay for something that is essentially free. Isn't air already like 78% Nitrogen?

It has larger molecules so won't leak, doesn't expand/contract as much with temperature variations. Won't "oxidze" the inside of your tires.

Give me a break!

I am right there with you but he swore up and down he has had zero tire pressure alerts since doing it two years ago. Maybe his sensors are broken

It would seem that checking your tires more often makes more sense than putting Nitrogen in them. For the $$, doesn't make any sense, to me at least.

For tire pressure, I would aim for higher pressures in the winter to avoid rim damage.

Originally Posted by johntube

It would seem that checking your tires more often makes more sense than putting Nitrogen in them. For the $$, doesn't make any sense, to me at least.

For tire pressure, I would aim for higher pressures in the winter to avoid rim damage.

If the nitrogen truly does not bleed down, which I honestly still am having a hard time believing. Then it boils down to how much your time is worth to you. I'd personally pay the $50 or so it costs at the local tire place if it meant avoiding dealing with topping off tires with every major temperature change. It also means I'd probably trust the tire sensor alarm more because quite frankly as much as it has gone off in the past it is not something I get worried about now days when it goes off.

Just put air back in it. I had.nitro. In my first car and was always having to mess around with the.presures because.it takes longer to warm up

Sent from my SPH-D700 using Bimmer

With temperature changes and regular "air" your should not be dropping 25% in pressure that would trip the TPMS. Even with nitrogen you should be manually checking your tire pressures. The one advantage I can see with nitrogen is protecting the TPMS sensors themselves. As it should have 0 moisture in it, would prevent any corrosion that may happen to the TPMS electronics.

Read this. Be sure and read the comments below as well.

http://www.popularmechanics.com/cars...stions/4302788

And this:

http://news.consumerreports.org/cars...nitrogen-.html

Originally Posted by KeithS

With temperature changes and regular "air" your should not be dropping 25% in pressure that would trip the TPMS. Even with nitrogen you should be manually checking your tire pressures. The one advantage I can see with nitrogen is protecting the TPMS sensors themselves. As it should have 0 moisture in it, would prevent any corrosion that may happen to the TPMS electronics.

It happened the past two winters in my car. By temp changes I mean fluctuations. Like one week in say the 70s then next freezing then next in the 70s and so on. The first winter I had this car the weather fluctuated really bad. The second winter not so much and this one is looking to be even more mild.

But again I do not believe nitrogen works past this.

All,

Quite interesting to read this thread. I drove my car last Wednesday for the first time in a while - all was kosher. Thursday morning, I jumped in the car to take my daughter to school and the TPMS warning illuminated advising that the left front tire pressure was low. I subsequently checked the pressure on the tire (read 29psi) and the remaining three. Saving the left front, the rest were just a tad below recommended and I subsequently filled all to correct pressure. All is copasetic now.

My immediate thought was that I ran over a nail/screw and did not think of a drastic temperature change. Lesson learned...God bless wisdom!

-slug

Originally Posted by slugdriver

All,

Quite interesting to read this thread. I drove my car last Wednesday for the first time in a while - all was kosher. Thursday morning, I jumped in the car to take my daughter to school and the TPMS warning illuminated advising that the left front tire pressure was low. I subsequently checked the pressure on the tire (read 29psi) and the remaining three. Saving the left front, the rest were just a tad below recommended and I subsequently filled all to correct pressure. All is copasetic now.

My immediate thought was that I ran over a nail/screw and did not think of a drastic temperature change. Lesson learned...God bless wisdom!

-slug

I had something similar happen to me a month ago. Only my other tires were fine. I had my wife take it by the tire place. They topped that one tire off, reset the computer and not had an issue since then. But also had really mild weather too.

Air should be replaced every oil change to keep it fresh

Along with the blinker fluid every 10,000 blinks.

Originally Posted by BrianNC81

Air should be replaced every oil change to keep it fresh

Along with the blinker fluid every 10,000 blinks.

What about exhaust fluid? Oh wait, that joke no longer works does it ...

Originally Posted by Snipe656

I had something similar happen to me a month ago. Only my other tires were fine. I had my wife take it by the tire place. They topped that one tire off, reset the computer and not had an issue since then. But also had really mild weather too.

I had my tires rotated on the Tahoe but they didn't reprogram the wheels so it thought the rear tires were in front and vice a versa.

My wife had the car, got a low pressure warning for front left and looked out at it and it was fine, so she continued. Basically she ran the rim over the left rear tire so I had to buy a new tire.

It was hard to blame her for that, but I wanted to!