Hey guys,

I have no experience with cars that monitor the tires or with run flats.

I have a 2009 Cooper S with run flats and this morning when I started it, it told me "Low Tire." I got out and looked, but you can't really see on run flats is what I've heard. I went the gas station and check the pressure. All 4 read about 34/36. My manual says they should be 38/40 so I added some air and reset the monitor per the instructions.

My question is, how do I know the difference between normal pressure loss and something else? I didn't see a nail, but I also didn't know what tire to check. Is there a different warning for a flat tire? or a punctured tire?

Thanks in advance.

 

"Dimples",
Although I didn't experience an actual flat tire with my RF's, a friend did and the alert was the same as the low pressure. When he checked, the tire had 0 psi. Visually, he couldn't tell the difference. When this question was asked in other posts, many indicated that more than "moderate" temp changes would cause the system to alert as well. When I rotated my tires, I got the alert because it knew there was something "wrong" and when I put on the new tires, it did the same. After a reset, it went away and didn't come back.

 

Thank you, cmcveay.

I guess I will wait a few days and see if the warning comes back up.

 

The BMW/Mini dealer told me that this isn't really a sensor system like TPMS that detects the pressure in the tire, but instead it detects changes in the circumference.

Is this the case with the R56?

 

In my previous 350z, the system would give you actual tire pressures for each tire. That would have been nice in the Mini.

 

With Run Flats, it is difficult to know if a tire is truely flat, especially when driving. The tires never really look flat because of the stiff sidewalls. The warning is the same regardless of it is 1 psi lower than the trigger point or zero psi.

Bottom line is you still need a tire pressure gauge. Too bad Mini does not have the TPMS that gives you the exact tire pressure.

 

I got that waring a couple weeks ago as well. I checked em and they were fine. Just figured it was the drop in temp that made the warning go off...

 

No, the R56 has a TPMS that measures tire pressure.

 

Man, dealers really need to get their act together.

So, for winter wheels, I definitely want to get new sensors? Sorry for the thread jack.

 

I guess I better buy myself a tire pressure gauge. But otherwise it sounds like for now, I don't need to worry?

It was just odd because I drove to SF yesterday. But last night it did get colder here than it has been.

 

If you want the TPMS to work you will need sensors on the "new" wheels since you have a 2009 R56. Otherwise, there will be that annoying yellow light telling you that there is a problem. If you buy run flat winter tires, I would get the TPMS.

 

Tire pressures are sensitive to the cold ambient temperatures. Mine has triggered because of the cold temps.

Get yourself a decent tire pressure gauge with a hose and bleeder valve. I like the ones with the straight chuck because I find them easier to connect to the valve and push down with equal pressure. But others swear by the ones with the angled chuck.

 

My understanding is that these go off with a thirty percent loss of tire pressure. I have NAV so as soon as I put air in the tire the sensors reset.
I am not sure how TPM works on a car without NAV. On the NAV screen it shows which tire is low.

 

Yet another reason I should have gotten NAV. *facepalm*

 

Correct me if I'm wrong, but I believe the newer MINI's detect tire pressure loss by the difference in wheel rotation. Older models (I don't know when the change occrued) did measure tire pressure. You can tell which one you have by the type of valve you have (if it is original). Metal valves measure tire pressure; rubber valves measure difference in wheel rotation. My '06 R53 had metal valves; my '07 R56 has rubber ones.

 

The 07 have the rubber stems (=wheel rotation sensor, not TPMS=tire pressure monitoring system). The 08's have the metal valve stem TPMS system because the law for runflats mandated it. It's a pain for people who have a different set of tires for snow because it costs a bundle to install the sensors into the wheels. If you really hate pressure changes try nitrogen because there's no water in the nitrogen and water combined with air makes for wider swings in pressure with temp changes.

 

Our '09 Clubman threw the tire warning the other morning after an overnight cold snap. Checked air pressure and all tires were equal, but had lost a few pounds of pressure. That thing sure is sensitive! A tire gauge in the glove box is a must have.

 

Thank you all so much!

I was admittedly freaking out a little this morning because I had no idea what to do. Automatic scared girl kicked in.

But you have all calmed my nerves.

 

Well if you got a flat it will keep tripping the sensor so if it doesn't it is just normal air loss

 

if there is a couple of pounds difference you will get a yellow warning temp changes sometimes will cause. more than 5 or 6 I get a red warning need to check closer.

 

... except here in Canada. My '08 has the rubber valve stem, rotational-speed-sensing system with no in-wheel sensors. All Canadian Coopers have this system, AFAIK. They still call this a "TPMS" because it does monitor the pressure in the tires, just in a different way. I have read that Canada may mandate the in-wheel-sensor system in the future because it is supposedly more accurate.

My OBC threw a low-pressure code two or three times last winter soon after I had purchased new winter tires and 15" steelies (with no in-wheel sensors, of course, because they're not req'd). It turned out that one of the tires had a tiny pinhole in the sidewall, almost too small to detect but enough to bleed off enough pressure to set off the warning after a week or two. Tire dealer replaced the offending tire and no more warnings. So, the TPMS system in my Canadian Cooper has proved its worth to me already, less accurate system or not.


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The standard Cooper comes with a Spare and no Run-Flats, yet it still has metal valve stem TPMS Sensors.

Think that the US rule applies to all autos built after August, 2007.

 

Dimples: get a good tire pressure gauge. I like this one, YMMV. For now, check your tire pressures daily, until you are sure that warning was just a fluke (temp related). After than, check your tires at least every two weeks.

Whenever you add air, rotate your tires, or change tires, reset the TPMS.

In Sept 2007, the US Government required all new cars to come with in-wheel sensors that measure air pressure. I believe these all have metal valve stems. In the USA, this system is called TPMS (Tire Pressure Monitoring System). My April 2007 MCS has the rotation based FTM (Flat Tire Monitor).

Neither system is very sensitive and should not be relied upon for making sure your tires have the proper air pressure. The TPMS can lose 30% percent or more pressure before issuing a warning. It can also be triggered with less change. In short, it is a fairly crude system that is just supposed to alert you when the tire is seriously low. Its purpose is to alert people in SUVs that they are likely to get killed by a flat-tire-induced-rollover.

To get the best life ($$ worth) out of your tires, and maintain maximum safety, you should keep your tire pressure within a few lbs. of the ideal pressure. Problem is, the ideal pressure is a little difficult to determine on MINIs. Depending on where you look, you can find anything from 33 lbs. to 40 lbs. My users manual says one thing, and the door sticker on the car says something different. It seems that if you carry four pasengers and drive 100+ miles perhour, you should use 38-40 lbs. The proper tire pressure for one person driving legal speeds in the USA seems to be more difficult to determine.

My thinking is that something like 36-38 lbs. for the fronts and 34-36 for the rear might be about right, but I haven't really figured out where the ideal spot is.

With the ideal pressure, you would maintain maximum grip (for braking and cornering), and the tire tread will wear evenly. With too much pressure, the center of the tread will wear faster than the edges, and you will have less than maximum grip. With too little pressure you will also have reduced grip, the edges of the tread will wear out first, and the sidewall may overheat from the extra flexing it has to do on every rotation. Overheating can cause the sidewall to weaken and break apart. IIRC, this was the kind of thing that lead to the catastrophic tire failures and resulting fatal rollovers that got Ford and Firestone into so much trouble awhile back.

 

My TPMS flagged a three pound loss and it was the same pressure loss in all four tyres.

The FTM would have ignored that, as it was equal for all four.

 

I got my winter tires and wheels a little over a week ago. Nothing was ever mentioned on the threads I was reading regarding which tires, changing tire, etc about getting the extra set of sensors (or trading them from one set of wheels to the other). My first acknowledgment that they would be needed was from Les Schwab when I inquired what their price was to mount the tires on the new wheels.
I don't want to keep dis-mounting my tires every season so I will be getting another set of the TPMS sensors.
Alex from Tirerack has the OEM ones for under $200 (before shipping, not sure what shipping charges are).
I am also trying to find out if the other sensors he offers do work with our OBC since the other ones do tell you the individual tire pressure on a separate display that doesn't cost much more.
Good luck!