All,
I had some rear tires totally worn down, 0mm left, slick tire., all 4 wheels are p-zero rosso. Front is still good.

Got the rear replaced with exact same thing. Brand new p-zero rosso N1.

At first I loved them. Vibration on highway was gone (obliviously)

I took the car out for a spin today. First time I drive it when it’s so hot: 32c or 90F, no cloud, very bright sun all day. Car is so unstable… at 70mph when changing lines I feel the car going left and right and so forth. It comes from the rear. Same if I give a quick steering correction on highway, I feel the rear of the car going left, right, left, right…

Tire pressure is 44 rear and 37 front. (as written in manual)

Is this expected from new tires? More tread so more room for flexion?
Is this cause by temperature? Warm make tire soft?

Thanks :-)

 

That is pretty normal for new tires, especially softer compound tires. That wiggly feeling will go away after you put some miles on them. I remember first time i experience that I almost turned around to go back to the dealer to demand different tires. Instead I called them and they said to give it a few miles to break them in. It worked. Hope this helps.

 

I just went thru the same thing and posted about a month or so. I ll look for the link, but it is normal for about 1000 miles as the rears break in. Even one of the tire company websites is familiar with this 911 situation and call it normal. If I find the link I ll post it in this thread.

 

http://www.tirerack.com/tires/tirete...65&PID=3144498

 

more info on this subject

http://www.tirerack.com/tires/tirete...65&PID=3144498

 

Reduce the rear pressure. I am assuming those are cold pressures. With it being 90F, the rears are probably around 50 which is probably why it feels funny.

 

Thanks for the reply.
Yes pressure was an issue and the first thing I have checked. They were at 52 after 30 minutes drive. Reducing it to 44 made it better. But still…

I have also done about 300-400 miles with them (highway only)

Does alignment can play a role in this?
Porsche standard is 1.5 degree of camber for rear wheels. Before installing the tires, I went for alignment and ask the rear to be 1 degree camber. Alignment guy told me that would help prevent the car from following holes made by too heavy trailer trucks. Could it be the cause of my issues?

thanks

 

These vaues are for a full load (2 persons plus luggage) and are way too high for everyday driving

For a partial load ( up to 2 persons), which will be the case most of the time, the values are rear 37 and front 34.

 

These vaues are for a full load (2 persons plus luggage) and are way too high for everyday driving

For a partial load ( up to 2 persons), which will be the case most of the time, the values are rear 37 and front 34.

 

I didn t touch the rear alignment as my tires wore perfectly... what did your tires look like? I m sure an alignment can change things, how much I don t know?
At 400 miles I still wasn t happy, when you double that you should notice it gone if there is nothing else wrong. I just couldn t see touching everything when it most certain was the new tires.

PS, you should be checking and setting tire pressures with it cold. The manufacturer allows for temps to rise when in use.

 

New tires are squirmy due to mold release that takes 200 or so miles to wear off and then the taller tread will squirm under hard corner forces. Also your air pressure of 37/44 is too high for performance driving. The pressure on the door is the highest full load of 4 passengers and luggage. See your owners manual and you will read that normal load up to 2 passengers and luggage is 33/39 for narrow body Carrera S and 33/37 for wide body Carrera 4 S and Turbo's.

Also have you had you car aligned? If not do it,,,it makes a world of difference when properly done correctly...and the dealer is not the place to go usually for this.

 

This is normal with new tires. It's almost entirely due to the higher tread. Do not worry about "mold release." Car tires get scrubbed in extremely quickly and many issues people attribute to "slippery mold release" are really just due to cold performance compounds being hard due to lack of heat.