Jump to content

The RennTech.org community is Member supported!  Please consider an ANNUAL donation to help keep this site operating.
Click here to Donate

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Recommended Posts

Hi all,

Has my luck finally run out?

We took out Cayenne to a local wheel-refurbish company, and asked them to swap some tyres around (and fit some part warns) as ours were getting a bit bald.

Since we have had the car back the car lacks a bit of throttle response (gentle 20% throttle) between 0-30mph. At this time, when steering, the Traction Light flashes ('A' in a circle with an arrow).

Then when I go above 37mph, this is when the fun really begins:

The car starts a thud,thud,thud,thud,thud fairly quicky (5 per second), you can hear it and feel it in the car, almost like putting a shoe in a washing machine, which initially prompted me to think there was something in one of the tyres.

And as you increase speed to 45mph the thuding becomes LESS rapid, more like: thud, thud, thud, thud (2 per second). After 45mph, the thudding is the same frequency, regardless of increasing speed, or if I down-shift.

The previous owner told me the cardan shaft was changed about 25,000miles ago (although I dont have proof).

Any ideas what this could be?

Although speed related, the noise doesnt change directly proportionally with the speed of the car, or with the engine revs.

My limited guesses would be: cardan shaft, driveshaft, hub, gearbox, dislodged electical connection. But they are guesses!

Any experienced viewpoints? Before I take it to the specialist?

Thanks! and I will keep you posted!

Ger

Link to post
Share on other sites
    You can remove these ads by becoming a Contributing Member.

Considering that the traction light flashes, check your tire sizes, not just on the sidewall but measure the circumference. If the difference is more than an inch, the abs may be reacting. The sound you describe could be the careen shaft also.

Link to post
Share on other sites

I would visually check all the tyres sounds like one may have delaminated or even two? The traction control light is the yellow flashing triangle which may be a poor fitting tyre that has not sealed properly, had thus with mine when I went round left hand corners at speed transpired the rim had a small crack which meant the bead would not seal. Hope this us of some use

Link to post
Share on other sites

Thanks guys - Im thinking after a visual check - the natural next thing to do would be to go back to the alloy wheel refurb guy, and ask him to fit my original tyres, for a fair test.

How can I visually diagnose delamination?

Link to post
Share on other sites

The 274 seems odd, sure it's not 275. Your back tyres have a different rolling circumference from the front tyres. The second figure is the aspect ratio. It measures the height of the tyre off the rim as a percentage of the width. The "45" tyres are bigger and therefore these wheels turn slightly more slowly than the wheels with the "40" tyres for any given speed. If this difference exceeds a certain tolerance the ABS senses something is amiss. I don't know what that tolerance is.

Having said all that it, could be a slack wheel nut as that can cause knocking noises also.

H

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.