After changing tire pressure it is necessary to re-initialize the flat tire monitoring system.
The Owner's Manual lists three steps:
1) Start the engine, but do not start driving.
2) Press the button (forward of the e-brake) long enough for the indicator lamp to light up for a few seconds.
3) Drive off.

Then there is a comment:
It takes a few minutes before the Flat Tire Monitor can detect a flat tire and issue an alert.

Does anyone know how long (or far) the car must be driven before the system has re-calibrated itself? Am I the only MINI owner that cares about picky stuff such as this? Am I being overly ****? Am I asking too many questions?

 

In my experience it takes about 20-30 seconds for the flat monitor to reset...

Usually I do it driving away from the air pump, by the time I'm out at the street it's done blinking

 

On a thread called tire pressure I asked if you had to reset after adding or taking out air and it would appear not

 

Don't know if this is helpful or not, but I got new tires yesterday. I drove for atleast 35 miles before I noticed the flat tire indicator flashing on my Tach. I held the button down while driving--didn't bother to read the manual. After about 20 seconds, the flashing stopped and disappeared.

Guess I'll reset it again since I'm home now. LOL. It's funny though, I don't think the flat tire indicator was flashing for those 35 miles cause I'm sure I would have seen it!

 

I've done it three times - once after mounting the new wheels, and twice since after changing the pressures - and it's worked differently for me.

Each time I've waited until I got the warning and then I followed the instructions - start engine, hold button until the light remains on steady, drive off. I've driven as little as 10 miles and as much as 38 miles, and each time the light remains steady on until I switch off the engine - then on restart the light goes off as it should.

 

I just destroyed a runflat because my light never came on

 

Hmmm...You should definitely reset it after adjusting the air pressure in any way. Otherwise the monitoring won't be accurate.

 

I don't know about anybody else but I change tires CONSTANTLY (whe the sucker is running anyways) and I have never, ever done anything other than ignore the light for anywhere from a few seconds to a couple of minutes and it goes off. So far, it hasn't caused any flats......