Weird problem
 

I have a dumb question here.When I first bought my car a while back I was driving on the highway and it felt like I had a bent rim on my front right wheel. The next day I got back in the car and drove the same speed in the car and no wobbly feeling in fact nothing. At this point I went to a tire shop and had my wheels balanced and asked the tech if my wheels were bent. The tech told me the wheels were "true" and that they were balanced correctly. So , now my question is could it be my ball joint? If so would this be in deed the ball joint? If it is in deed the ball joint then would this work to replace it? What is a outer ball joint? I thought there was a upper and lower. I need to fix this problem cause at high speeds it feels like my wheel is going to wobble right off.


http://cgi.ebay.com/ebaymotors/Porsche-986-Boxster-S-Tie-Rod-Front-Outer-ball-joint_W0QQcmdZViewItemQQ_trksidZp3286Q2em20Q2el111 6QQhashZitem260291655448QQitemZ260291655448QQptZMo torsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

The ball joint wouldn't likely be intermittent, if the rumble is speed sensitive it could still be a balancing problem. A road force balance machine is best but the cost is higher and finding them can be tough. We have a lot of rubber on these cars, road inconsistencies can provide some of these experiences.

MY car does the same thing. I have had the wheels balanced, road force balance and checked. At 75 the wheel shakes every 4 secs for about 3 sec duration. the faster I go, the faster the delay in shakes, until it is constant shaking at about 90. then somedays it is smooth as glass.

I have no idea what this could be....any ideas would be great.

I just ordered Front wheel bearings... not sure if that is going to fix the problem but I might do this first then to the tie rods.

Does the car sit for extended period of time? Maybe minor flat spots that just need a bit of time to work out. Long shot I know.

Does it happen only when it's cold? A hunk of snow or ice (or rat) inside the rimwill do that .

Regards, PK

My car is a daily driver, the weather is warm here in texas and there is no ryme or reason that i can see.
I have balanced the wheels at least ten times and the problem still occurs.
I have changed rims, the problem is still there.
I am about to put new bearings and disks on it to see if that works.

The only thing I can think of is that both front tires have something that is rotating out of balance, and from time to time they become somehow harmonically out of balance and they shake.

But i have timed it and it is very weird, at 75 it shakes for 3 secs every 4 secs.
I am clueless as to what is happening.
Porsche cant figure it out either, they advised to change everything that rotates in the front.

James

Do you have aftermarket wheels? Some aftermarket wheels need a ring so that the centerbore of the wheel is the same as the center hub width. If not then the wheel (even though its balanced with the tire) can get out of balance. And this out of balance situation comes and goes depending on how the wheel hits potholes and bumps. It can seem perfectly fine for hours and then for no apparent reason go out of balance.

OEM wheels are machined to exactly fit the center hubs. Aftermarket wheels usually have bigger center bores so they fit lots of cars. Then the wheel seller should include rings for your specific car. If they did not or they were not back put on when tires were changed you can experience the exact problems you report.

I have stock wheels on and still have the problem. I am thinking it has to do with the wheel bearings or the tie rod.. cause that is the only thing i can think of.. The fact it happens once in a while makes me wonder. No matter what the weather is it does it..

What brand of tires?
How long have they been on the car?
How much tread remaining?

What brand of tires? Toyo
How long have they been on the car? less then 1 yr with less then 7k miles
How much tread remaining? Plenty was just checked by Goodyear speed shop.

have your tires checked to see if they are "out of round" This will also cause the shaking even though they are perfectly balanced.

I had great luck just checking tire pressures...

I drive mine every three or four weeks and noticed the same problem after a while - also right at about 73-75 mph... It drove me nuts until I read about how import tire pressures are for club racers... Anyway, I got a digital pressure gauge and made sure both rear tires were at 32 psi and the fronts were at 28 psi and the shimmy at 75 is gone...