Shaking over 70 mph, soooo confused
 

As the title says, my 986 1997 shakes like it needs a balance over 70 mph. I have had all 4 wheels balanced numerous times and rechecked more. Tire pressures are the same and good...I don't know what it could be. It's deffinately not the engine or trans. Steeringwheel shakes and car occasionally shakes. Gets progressive with more speed. Should I try another balance shop?

You should also check...
 

... the tire's tread.
It could have a bulge or the wheel could be damaged.
Happy Boxstering,
Pedro

I hear you. I had to have my tires balanced three times before they actually got it right.

The last time I asked the manager to tell the tech to spend an extra minute and be sure that he got the balance right for high speed running.

Also be sure and ask for them to use the glue on weights that balance the wheel in two axis (axes?) and not the cheap crimp on weight on the inner wheel lip.

I have the same problem and am looking for answers. I need to have a rebalance done asap as this 70mph shimmy bugs me like crazy.

Let your fingers do the walking & call the shop first & ask if they will do a " dual plane backside dynamic balance to 1 gram tolerance with stickon weights" if they can't or won't keep searching.

Is the car modified at all? I chased a similar issue that turned out to be lower quality front spacers. Even after balancing the problem remained. I will only use H&R's now, lesson learned. I also noticed some vibration at freeway speeds before I replaced frt engine mount, but that won't cause steering wheel to shake. Just FYI.

Thanks byprodriver. I will call around. Is this type of setup familiar to shops?

Tread is good and no bulge. I can't believe how many others have this problem!!! It sucks ;). I'm going to try a more well known tire place and let you all know.

With the current trend of hiring cheap inexperienced labor maybe not, but should be part of balancing 101. Dynamic balancing measures lateral or side to side balance as well as static or up & down balance & is indicated by having weights on inner & outer edge of the wheel. Backside means all weights are positioned behind the "face" of the wheel.

check your suspension , something might be worn out.

Perhaps try a Road force balance on a Hunter GSP9700...

It's possible, but I wouldn't know which component to check...any advice on what part of the suspension would cause my problem?

it happened to me before when i drove at 90km/hr+... i tried over 230km/hrs and felt like i'm driving a boat on a lake.

I had this bad experience after i installed a replica wheels.
you can try to ask the shop to do wheel/tyre alignment with a tools that looks exactly u put on your car with 5 screws on. (don't use the center cap hole for wheel/tyre alignment)

If this problem keeps coming out, try to change your wheel and test again.

in my case, i finally install an original 18" wheel from 987.

Just set up a road force balance with my local shop.

Checking for worn components is easy, jack the wheels one at a time (unless you have a lift) check for play at 12&6 and then 3&9

Good deal, these usually seem to help a lot. Hope this works for you!

might want to also loosen all the lugs and tighten criss-cross at 20lb intervals. I had a similar problem last year, and it seems to have been the difference with mine. ymmv

man was there a time when I needed these words ready to roll of my tongue!

Hmmm, voice of experience? ;)
I saw your pictures on your site... :D I'm hoping to join you one of these years!

I do hope the balancing takes care of it, though.

UPDATE : Car has been at a Road Force shop with the proper gear and its NOT the what we thought:confused:. Looks like the tires might be the culprit as previously mentioned. Shop said that Heavy "V" directional tires might be to blame. Has anybody heard this before? They are going to put 2 tires on the front and we are going to give that a go and see if it works:). If so I will update.

Current tires are have a very aggressive V pattern now so I am having shop place a good low pro non directional tire on to see how that improves the "SHAKES".