Matt DMZ

Hello,

I am new to the forum, as I have recently purchased my first 911, a 991.1 Carrera S

I appear to be experiencing something strange when cruising at normal speeds, such as highway driving. I am noticing that sometimes the rear end tends to slightly pull off to the side, and then is quickly corrected. It is driving me crazy, because I cannot effectively duplicate the issue, but it happens frequently. Like I said, my first 911 so I have no experience to compare this too. I am not sure if the tires are just tracking with contours in the road because they are so wide, or if something weird is happening with the diff. Any advice on this would be greatly appreciated. It feels like the car receives a small jolt, similar to if you were driving along and a strong gust of wind suddenly broad-sided you for a split second.

Otherwise I am in love with my new car, I can see why everyone loves these things so much!

dflowerz

Sounds strange to me. Is the car a CPO? I would have someone look at it for sure. Tire pressures OK?

StormRune

Rear instability is often a result of incorrect toe-in on the rear wheels. Zero toe or toe-out is really unstable. You should probably get an alignment at a proper Porsche-literate shop, I just use the dealer myself.

StormRune

BTW, if you do get alignment, ask them to give you the sheet showing both before and after numbers. Many shops assume that the customer doesn't care about the specifics, but I always like to know where it was and where it ends up.

DerekS

How many miles are on the tires? Some brands get really slippy when they need replacement...and the rears generally wear at 2x the rate of the fronts.

Duke I

Mixed tire brands and specs? Front/rear mixup?

R_Rated

Your rear tires are Gone! The outside tread may appear fine... check inside and toe.

LexVan

It's called tramlining. Becomes more pronounced with worn out tires.

Dennis C

I used to experience this when I lived in the Midwest, especially on asphalt roads that were frequently used by 18-wheelers. The truck traffic causes subtle depressions in the road, and these can cause your Porsche to behave the way that you described.

Porscheforever

I had the same experience as you. In my case it was not the tires. It was considered "normal" in 991.1. The only answer is to add wings and front skirt (ground effect option?) as it will eliminate the sudden jump from the wind.

Churchill

It's not normal, aero won't make any difference, and 991's do not "suddenly jump" from the wind, unless you drive into a tornado.

LTP

mine doesn't really kick out, but I can feel there is a lateral movement in the suspension or tires.

its a weird feeling.

Dewinator

Did you blow 2 million yen on a lambo just because your 911 was aligned wrong? Whoever considered that "normal" was an idiot.

R_Rated

Daohaus

mine's not as pronounced but i can feel when the car is tracking the freeway roads, it happened on my 997.2 as well.