So I noticed the warning bars showing on my rear tires (275/30ZR19), 2008 550i with M package, which currently have Continental's on both front and rear. The front tires look to have a good bit of tread left before I get to the warning bars.

Would it be wise to replace all 4 tires at the same time or just go with the rears for now?

Thanks!

 

I feel it'd be OK to replace the worn rear set now and the fronts when they have a few more miles on them. That said, with the tread wear indicators showing I'd be very careful driving on wet roads until you get re-tired!

 

I just went through this and also have a 2008 550i. I had 7/32 left on the front, but one of my rears had a bulge in the sidewall. Talking to my tire guy, he stated that the rear tires tend to wear quite a bit faster than the front (2:1 rear/front, possibly). He suggested just replacing the rear and by the time they are worn down, the fronts will need to be replaced as well.

There was also a cost factor for me. Just my $0.02

 

fk453 are under 200 bux a tire, recomend nitrogen!

 

What are the big differences filling with nitrogen?

 

For most drivers the only difference they'll feel is their wallets getting lighter by about $25! Nitrogen is used for certain tire applications where there is a wide variation in temperatures the tires will encounter [e.g Airplane tires] as it expands and contracts less than air.

Since car tires aren't usually exposed to these temperature variations ["real" race cars excluded] to the extent that inflation pressures would change dramatically this is another case where the marketing guys are hard at work figuring out ways to get into your wallets.