Bruce In Philly

Ya know? It may be the lateral control arms in the rear. Are you getting an odd clunking back there?

Peace
Bruce in Philly

ADias

Take it to a competent dealer and have it checked. And never floor a car before the engine is up to temp and the tires are hot.

onewhippedpuppy

If it's that bad, there's an issue. Have you had the alignment checked?

cjjones

Just my 2 cents.

My experience with this was my right rear wheel hub lock nut was loose. Under hard acceleration her *** was all over the place. Took off both rears and found that I was able to wiggle the rotor (and consequently the hub) on the right rear. Check that lock nut.

Windy Water Boy

Thanks for the feedback - a trip for a dealer checkup is calling.....

Macster

By all means have the car checked out. While the squirming is probably normal it never hurts to be sure.

I've actually had my Boxster squirm so bad I've pulled over thinking I had if not a flat tire a low tire. Tire pressures were found to be ok. These cars can really feel weird with worn tires on some road surfaces.

PVKPorsche

The sympton sounds like a situation where someone installed standard load rated tires on a car that needs XL load rating but I doubt that Pirelli size comes in a standard load. I say that because I had replaced the tires on my wifes Boxster and the shop accidentally ordered standard load vs XL. The car was very squrimy, swayed quite a bit and a little nervous to drive. Someone mentioned control arms which could replicate the same but surely with 30k miles he wouldnt be having that issue already? He is in Dubai and the roads are as smooth as glass so not pothole concerns to wear out the suspension. Very odd. Windy Water Boy, check all of the tires, just make sure each one of them shows an XL load rating which shows on the sidewall near the tire size. Its a quick simple way to rule that out.

The other question, has it been this way since you have owned it or it just cropped up?

Windy Water Boy

Thx for the comments - The fronts are 235/35 ZR19 87Y Standard Load, whereas the rears are 295/30 ZR19 100Y Extra Load.

I would have imagined this is correct as all the weight is at the rear.

There are no clonks from the suspension even though there are loads of speed humps in Dubai.

The car drives straight and without swaying when at constant speed - the swaying is only during brisk acceleration - oscillations are about every 0.5sec I would guess - like wiggling fairly hard in an office chair.

Windy Water Boy

I have only owned the car for a couple of months and I think it has been there all along (and the car was checked for a 2 year warranty extension by the main Porsche dealer. I spoke to the previous owner who had the car for 2 years, and his thoughts were along the lines of tire pressures and road camber/bumps unsettling the suspension. However I don't think thats it.

Previous owner had had a flat tire that damaged a wheel rim, so he replaced both rear wheels and had the damaged rear re-machined (and the other rear machined to match). He is an engineer by profession and seems a nice and straight guy, so I'm hoping there isn't anything ugly lurking.

Will get it checked at the dealer, but having heard that they can be a bit "creative" with their work generation I'm happy to keep hearing any comments/suggestions from the forum to act as a sanity check to what the dealer may say....

PVKPorsche

BINGO, i am pretty sure you just located the problem. Ask TireRack on this forum to be sure but i am nearly positive two different load ratings is your cause. You have fronts and rears with different ratings that flex in different manners which is causing the squirming. One tire flexing more than the other. Our cars should have XL at all times but even if not, I am pretty sure you should never mix them.

user 72902

+1

Start your diagnosis with four proper matching tires.

Macster

Just a heads up: Porsche does not sanction any welding/machining repairs for its light alloy wheels.

Windy Water Boy

Thanks for the comments. However, I don't fully follow the logic for requiring XL both front and back on a 911 - as I see it XL is typically prescribed for heavy axle loads such as a full complement of people and luggage in a station wagon / engine slung out the back in a 911. However a 911 front is lightly loaded - the only issue is the high speed. However I am very happy to be corrected by any tire experts out there )

The tyre manufacturers' websites seem ambiguous too:

The Michelin UK website recommends Pilot Sports with normal rating at the front and XL rating at the rear:
http://m.michelin.co.uk/tyres/michel...1-531615-49604

The Michelin Canada site recommends Pilot Super Sport with XL for both front and rear.
http://www.michelin.ca/tire-selector...t/tire-details

But the same site recommends standard load front, XL rear for the Pilot Sport PS2

Either the different models of tires have different characteristics and hence different load requirements for the front tires, OR the guys who set up the websites aren't too precise with the details........

And the Pirelli website doesn't mention XL for either front or rear, so I guess that useful detail didn't make it into their website configurator matrix....

Windy Water Boy

Thanks Macster - will treat the machined spare wheels with circumspection.....although anyone who has scuffed their wheel on the kerb and sent it to be refurbished is in a similar non-sanctioned boat I imagine. I recognize Porsche won't sanction it as they have no control over extent of damage/care of repair but I doubt people buy new wheels for every scratch. I also have a funny feeling that the majority of Porsche dealerships send wheels on trade-ins to be refurbished before putting the cars up for sale in the showroom rather than putting new wheels on the cars.....

DC911S

One of my wheels was refinished by the dealer prior to my purchase of the car. Now that's not the same as fixing a bent wheel or other major damage.