Diagnose this...I know you can
 

ok I see from the post that many of us has had this problem. So maybe you can all collaborate and help a 986er out.

the problem: steering wheel vibration at around 67mph.

observations: allignment fine, tires sumi htrz2, H&R 15mm spacers all around. ballance 4 times in the last year. last time ballanced ( 2 months ago)on hunter 97XXX one wheel off by an ounce. after this ballancing my vibration in the car and steering wheel got better.

Now: I took out the wheels to install my beautiful gemballa bumper and after putting them back on tight i have the vibration again but this time at 67mph-70ish, instead of 80+mph like last time.

what do you think is the problem? should I take it to a shop and have them put the wheels on and machine torque the screws? or should I re ballance the front tires again?

thank guys!


this vibration really sucks

Did you torque the bolts correctly?

yea my friend put on the wheels so I hope it was done right. and hey werent you the guy who hit the side rail on the porsche drive? I spoke to you in santana row, hope all is well.

could be alot of things, but did you by chance knock off a wheel weight on that wheel? Go get the wheel balanced and see if it goes away.

I have a similar problem in one of my daily cars - flutter/vibration at about 65. Tried balancing at 2 different shops, did alignment twice, no avail.
I wonder if one wheel is screwed up? The price of a wheel is not excessive, and the vibration drives me nuts, so I may buy one with a matching tire and start moving it around the 4 corners to see if that works.
Good thread - curious to see comments of others -

im also thinking that either a weight was knocked off, or not torqued correctly.

btw, any pics of the new mod? ;)

1. Front tires out of balance/out of round/ beginning tread delamination. A good tire tech should be able to spot this. Once in a while you just get a bad tire.
2. Front suspension worn bushings, struts, etc.
3. Bad front wheel bearing.

Eliminate the front tires first. You didn't say how many miles on the car or suspension but if the tires are A - OK then it's time to get it up on a rack and have the suspension looked over by someone who really knows these cars.

Front end flutter is not something to ignore. Good luck!

Best thing (and possibly the cheapest, compared to suspension work) to try first is replacing your tires. I had a brand new set of Kumhos I could never get balanced right. The day I replaced them, I thought I had bought a brand new boxster the ride was so smooth... and the tires I replaced the kumho's with were cheaper tires too! (sumitomos).

Im gonna check to see if a weight was knocked off then possibly take it to have them put on again so i know they are sitting right. the car hs 26,800 miles on it for those who asked. My fron tiresare more worn than my rear ones but they are worn on the insides more due to tire pressure that I fixed a long time ago. I have changed my steering wheel and airbag a while back but im sure it was mounted on correctly ( although it seems a little off 12 o clock). Its not wheel bearing cuz a porsche tech looked at it, and its not suspension. I was told last time it may be due to the characteristics of my tires.

as soon as my digital camera works again you will see some nice pics I promise

I developed this problem recently. I had the tires rebalanced and found out my passenger front wheel is out of round. I'll look for a replacement front set.

still dont know whats wrong
 

I thought my tires were out of round last time but they said it wasnt. so its not out of round, wheel bearing is ok, been ballanced before. I think I may re balance again and in the future get better tires.

so I figured out at speeds 65-75mph and even higher the steering vibrates alot but under acceleration its less. when its not accelerating it comes back on. anyones had similar experiences?

Lol yep that was me. I was going to try and find you on 6speedonline to talk to you about your side skirts and rear diffusers. Dude your ride looks BAD(in a good way), I didn't know that was yours when I talked to you.

Hey did you meet the guy who had the Artic Silver Boxster with the carbon fiber hoods and custom rear bumper? I think his license plate was 'EUROPWR" or something like that. I wanted to know what he did performance wise to his car.

*Dude you had me jonesing for PSM that day.

How old are your tires? (you may have said, I just wasn’t paying attention) I’d a pair of tires which were just to old to keep me in my lane. Composition of the rubber evolves, after 4 years max their spent regardless of the tread.

PK

A few thoughts?
 

You have 18" sport classic I wheels with 15mm spacers all around and the standard sport suspension (i.e. not the ROW) --- is that correct?

If so:

1. How good are your spacers? I have seen a few shoddy ones that are off in thickness by a fair bit -- not 15mm thick all the way around. If so your wheel alignment will never be right. Are they hub centric? Are they installed correctly?
2. What did you align to, USA or ROW specs? If you have the USA sport suspension the specs are the same as standard. But if it is ROW, the specs are different. Did the alignment shop realize you had spacers on? Did they have the correct specs?
3. Did you replace the lug bolts with longer ones when you installed the spacers? With 15 mm spacers you should be using 60 MM lugs I am guessing. Or they could be spacers with lugs attached?
4. How old are the tires? Wear on the inside only is usually a sign of an allignment problem negative camber. If you changed tire pressure to get more even wear and the tires were really thrashed on the insides, that could cause the vibration.

I would probably do the following in order followed by a decent test drive:
1. Remove a few lug nuts to ensure they were 60mm and have the cones. Then retorque them all to 96 FT-LBs. Torque every other bolt till all five are done -- first go to 80, then 85, then 90, then 96.
2. Remove the spacers -- fronts then rears. 15mm in front are pretty thick (IMO) -- I think 5 or 7 are more common with a stock wheel.
3. Realign and rebalance all wheels. Ensure the appropriate specs are used for the suspension ROW or US Sport.
4. Check/replace the front tires.

Tire rack has the linked chart that is more detailed with a few more options ... steps 1 and 2 above are free so what the heck (unless you need new lug bolts)

http://www.tirerack.com/images/tires/vibechart.pdf

Hope this helps.
ATB,
Tom

I got my spacers new so they should be ok. I have the 60mm bolts, I havent had the car alligned yet because it seems to tract straight, and it came with the us spec M030 from the factory. my front tires were used for about 3 months on a mercedes and i put them on when i put new ones (same brand and rating) in the back. I think the inner wear is because of over inflation. when i first had the car it was inflated to 40psi from the tire shop, I noticed it rode like crap so i deflated it to 33psi all around.

speaking of riding bad, my car is really stiff compared to other boxster's I have driven.

I think its the tires and ballancing since i hear our cars are sensitive to them. Im gonna get the fronts and the back ballanced this week.



hey Blinkwatt....yea I dont go on 6speed much but my rear diffusers are the gemballa/strosek ones which i realized look the same. The side skirts are OEM aerokit 1. They were impossible to find and totaly out in the US. I got hooked up and got both sides new for 500 bucks shipped(new) from germany, the diffuser was 203 bucks but i got it used. I got my gemballa front bumper from usher in atlanta. the lines from the lip on the bumper to sideskirt to the diffuser match so thats why i got it. The front bumper looks like the boxster special edition.
how is your car now?

Yea that guys car is everywhere online. I had it for my desktop wallpaper for a while. Then saw it at hot import nights, and he was selling it. Its 3.4L. its all aesthetic/audio mods mainly but he has headers intake, exhaust. It used to have a 2.7L that blew up after he put a supercharger.

There was another guy that day that had a slammed silver boxster, he also had a 3.4L and was putting out 340hp. He is the guy who invented the power top chip. he had flame throwers that shot out 3feet long flames at times. he had the loudest 986 I have ever heard. said his car went 0-60 in 4.3

lol,it's in San Jose in pieces.........I'm currently in the middle of butting heads with the insurance company.

I can't wait to get it back! It's going to be one very fast drive back to Sacramento. :D

I have had the exact same problem and it was a really bad at 70-75 infact it was really annoying, my front tyres were at 22psi and 24psi, i whacked the air into 30psi as per manual, (im currently 17" box S) and it was better but still not fully gone. I think there is a reason, my wheels were all balanced at OPC and i mentioned this and they found no reason.
mine is an 02 with 31k miles on the clock, never been crashed and full porsche centre service history. so there must be a reason,

James