I was driving early in the morning and got a flat on my NX_450+. I was not able to drive for more than a few hundred feet before 10 mph was the fastest I could drive. That was really disappointing for what I was expecting from run flats.

Maybe the type of flat matters. I ran over a downed street lamp pole lying across the street at about 25 mph. The tire pressure warning came on immediately.

Are the run flats supposed to work under any type of flat situation? May they only work for pinpoint leaks?

In any case, I replaced the run flats with non run flats. I'll just get a Modern Spare for long trips.

 

A street lamp pole? Better have the dealer check for other structural damage to vehicle. It could be why you got reduced speed.

I wouldn’t fault the RFT they’re not made to run over that kind of object.

 

Timothy, approximately what was the diameter of the pole and did both front and rear tires go over it.... was there a large hole in the tire and where was it on the tire...sounds like a pretty scary experience ...

 

Yea, that situation may be a bit removed from a standard flat to "collision damage". A run flat's ability to actually run flat is still dependent on the structure of the tire being intact, as well as the wheel and other parts of the suspension.

 

I'm curious if you got any message on the dash to say why 10mph? Supposedly, the tire can go 50 mph and 50 miles with 0 air pressure. The car otherwise wouldn't know what type of damage the tire sustained. Is this the first person to test the runflat car acknowledgement???

 

What happens both before and after 10 MPH?

 

My wife's 350h had a flat, a nail right stack in the middle of the tire and it ran fine around town. I checked the app, the flat was at 27 psi she didn't notice any difference but she did noticed the TPMS light lit up.

Went to America's Tire and they patched it.

 

Yeah, if you run over a 3 foot tall concrete block... I'd assume the run flats won't work as suggested

 

What was the damage to the tire? RFTs work for a hole/puncture in the tread area. If there is damage to the sidewall, the RFT won't always be good.

 

But it *can* still be good. My wife had an accident that put a pretty good gash in the sidewall and we were still able to drive it for a few miles to get it home and then to a local Firestone store a few days later after TireRack.com delivered a replacement tire to them.

 

Tim, how large was the light pole and you run over it with both front and rear tires....

 

The pole I ran over was probably 3-4 inches in diameter. I was going fairly slow at the time, since I saw the car with the blinking lights but not the pole.

When I ran over the pole, the tire pressure sensor immediately came on. I went for about one block before I could tell that the tire was flat. It sounded and felt just like a flat non-run flat tire. When I got out to look at the tire, it was completely flat, just like what a flat non-run flat tire would look like.

I'll get the dealer to look at the alignment, but I think it's okay. The car is not pulling to the side at all. Fortunately, I was going at a slow speed at the time.

 

I was under the impression that run flat tires COULD NOT be patched…

 

If they are structurally sound (ie side walls are good, they haven't been actually driven flat) and the leak is a straightforward puncture in the tread, there really is no difference in ability to patch. The difference between run flats and regular tires is that you can run them flat for a while. The thing that is the same is if you do run them flat, they are likely to be ruined in the process regardless of RF or regular.

 

There's more to alignment than just pulling to one side. Alignment that is off can cause uneven tire wear.