Shake in front end..

[Marc Gelefsky]

I have a minor shake in the front end at some higher speeds (70+)
I have 4 brand new tires, all balanced, checked wheels and they are true.
Thoughts?

My old 951 always did this no matter what I did, same issue? live with it?

Thanks

[MNBoxster]

Hi,

Were your new Tires Dynamically Balanced? There can be some great discrepancies between new tires and only by using a Hunter Dynamic Balancer (97XX Series is most current I believe) can you be sure that the Tires are within spec (they all are not or cannot be properly matched with their Mate).

If this was done, start thinking about alignment or possibly a bent suspension member (these are Alloy and can be bent from a PotHole, Speed Bump or hitting a curb, albeit lightly, sufficient that they introduce a shimmy such as you describe). Hope this helps...

Happy Motoring!... Jim'99

[Ronzi]

Front end shake, vibration, shimmy, whatever you want to call it is typically a tire issue. At times it can only be seen if the balancing is done on the car, a method not often used by your typical tire shop. If your tires have been (most likely) balanced and re-balanced off the car, you might poke around and see if you can find someone that can do it on the car.
A couple of other possible contributory tire conditions are out-of-round (relatively rare), and problems with uniformity, a manufacturing defect related to internal stresses caused during the tire building process.
Out-of-round used to be addressed by grinding the surface (usually the shoulders) of the tread, but I don't even know if they do it anymore.
Uniformity problems are uncorrectable, other than by replacement of the tire.

[RandallNeighbour]

find a "road force" balance machine such as a Hunter 9700 as Jim suggested. Check this website for a zip code search. My closest Discount Tire just installed one a month ago, which is nice to have close by... and cheap too. $19.99 a tire. The high performance shops were nearly double that when I called.

http://www.gsp9700.com/pub/search/findgsp9700.cfm

Other readers of this post should search too to find one nearby and make a mental note of it! Boxsters seem to be very hard to get into wheel balance and keep there. This machine really got my boxster smooth and vibration free after many, many balancing sessions at 4 different places!

[mjw930]

Yes, these cars as well as the 996's are a PITA when it comes to the mid 70's speeds. I just swapped out a used set of modular rims with BBS RS-GT's and brand new N1 Pilots and it's glass smooth up to 74 then it vibrates to about 90 then it smooths out to where it's glass again at 100 and above (don't tell anyone....). They were balanced on a hunter 9700 but it looks like I'll be getting it done again on a different machine, probably the one at the dealer. The have the 9700 and don't charge an arm and a leg for tire work.

[deliriousga]

Check your tire pressure. The shops never fill it properly when balancing. If the balancing really is good, then try an alignment. If the alignment doesn't take care of it then it's most likely a worn control arm bushing, worn ball joint, worn tie rod end, bent suspension part, worn wheel bearing, bad shock and/or spring or worn steering rack mount bushings.

That should narrow it down a little. Be patient, these things can really be a PITA to find if it's a worn part.