I just had a flat last night, on one of the rear tires. And with the top up, it was barely noticable. It didn't pull or anything, just made rythmic rubbing sound. I topped it off with air, and I'll get the nail tonight, but I'm worried that I didn't notice it soon enough to save the tire. Is this a problem with low profile tires? I've had flats in other cars and they were Very obvious, what I heard last night could sounded fairly minor.

 

Even with low profile tires, there is a noticable change in steering/driving feel.

Here's a tip. If you suspect something in wrong with your tire while you're driving (flat/low on air), just change lanes a few times and be sure your tires hit the reflectors in between the lanes. You can easily tell if a tire is low on air or flat by the feel and sound of your tires passing over those bumps.

 

With a flat front tire certainly. But the car went didn't pull to either side, though it didn't go all the way down to 0 psi, since it's a slow leak.

 

One obvious symptom is torque steer during shifting. I began to notice this one day on my new S and thought it odd that I had never noticed it before. The passenger side rear was down to about 20lbs.

 

I had a flat on the right rear (was down to 12 pounds) and I could easily tell once I was driving.

 

Just a couple pounds difference in the rear tire pressures will make the car pull to the left or right (depending on which tire is low) under acceleration. It's not really torque steer proper, but the car does steer when torque is applied and the rear tire pressures are uneven.

That said, tires with a taller sidewall do make flats a lot more obvious.