 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Car Forum / Porsche / Porshe 944 / January 2007Wheel shudder at 60 - 80 mph
My 89 S2 has a wheel shudder and I can't get rid of it. It is through the steering so I am fairly sure it is from the front. I have had the wheels balanced - I watched them do it and they got it right - but to no avail. I have read on various sites that this can be a problem with 944s and that the suspension is very sensitive. I find it difficult to believe that it can't be solved - or at least minimised. Does anyone have any suggestions? Many thanks Dave. 1. it could be the rear wheels also, that's worth checking 2. I had a tire that was out of shape cause this once 3. did they dynamically balance the wheels by spinning, or statically balance with a bubble level? If the latter, they might still not be balanced right > My 89 S2 has a wheel shudder and I can't get rid of it. It is through the > steering so I am fairly sure it is from the front. I have had the wheels [quoted text clipped - 8 lines] > > Dave.  SignaturePosted via a free Usenet account from http://www.teranews.com Noble has it right. You need to check the roundness of the tires. Place a stationary object next to the surface of tire when jacked up and spin tire slowly to see if distance from object to tire changes. You may have a flat spot from parking in cold weather and driving off too fast before the tire can reshape. Also, toe in may be out. If you have play in tie rods there could be a problem also. Michelin is the only tire with steel belts , I believe. Other belts made of synthetic fiber have a good memory in cold weather and will cause problems. I have an 84 944 with no shudder in front end up to and over 100 mph. Yokohama tires. A bent rim or defective tire could also cause the same problem. Other things to check, in case the vibration happens when you're turning a little bit: -Front wheel bearings -Control arm ball joint -Caster mount -Lose tierod end -Wornout steering rack mount Can you tell us how old the tires are? And when you last had a 4 wheel alignment? Good luck! > Noble has it right. You need to check the roundness of the tires. > Place a stationary object next to the surface of tire when jacked up [quoted text clipped - 6 lines] > I have an 84 944 with no shudder in front end up to and over 100 mph. > Yokohama tires. Many good suggestions - thanks for those. I watched the guy balance the wheels dynamically but he did not balance the backs - this is my next task. The car was left in a dealer's for a long time before I bought it, so a flat spot may be an issue. The backs are Goodrich but the fronts I think are a budget make ( warning bells ringing here ) but they have decent tread on them so new tyres at £100 a corner is a lot to pay if I can solve it otherwise. I have checked the suspension and ball joints and everything seems rock solid. I did actually swap fronts for backs ( yes I am aware they are different rim sizes so I was very careful when I drove it ) and this seemed to have reduced it somewhat. I will get the backs balanced and if that does not cure it I may shell out on some decent fronts. I will keep the group informed if I discover anything. thanks for the suggestions. dave > A bent rim or defective tire could also cause the same problem. > [quoted text clipped - 21 lines] >> I have an 84 944 with no shudder in front end up to and over 100 mph. >> Yokohama tires. There is no problem with swapping front and back tires for testing -- the size difference is for handling purposes. I need to add a disclaimer here: on YOUR car there is no problem with swapping the front and backs. When you get into 9" and 10" rims, the offset for the rear will cause the rim to rub the spring on the front strut, so don't tell your buddy, with a 930, that he can swap the rims front to back, 'cause some guy on the net said it was possible. On some cars it is not advisable, but on an S2 which runs 7" rims in the front and 8" rims in the back, you will both clear the caliper and clear the spring. As for the cost of new tires, it sucks to spend that kind of money, but think of it this way -- the tires are the ONLY interface between your car and the road... Tires make the #1 handling difference and will determine if you enjoy driving the car somewhat, or if you're maddly in love with the performance the good engineers at Porsche so thoughtfully provided you in such an economical package -- a used 944 -- and you swear never to drive another car again! (That's roughly what happened to me) :) Good luck! > Many good suggestions - thanks for those. > [quoted text clipped - 47 lines] > >> I have an 84 944 with no shudder in front end up to and over 100 mph. > >> Yokohama tires. I have this same problem on my 944. The wheel bearings are very difficult to get them adjusted just right. It affected my wheels wobbling and when I brake you could feel the wobbling through the brake pedal. Any looseness in the following tests indicate either a loose wheel bearing or the indicated part needs replacement. First try to tighten the wheel bearing - if that doesn't work, then it's the indicated part. 1. Raise a front wheel and hold the wheel at 275 degrees and at 90 degrees. Move the wheel right to left and try to wobble it forcefully. Any play there? That would be the tie rods - or wheel bearings need adjusting. 2. Now hold the wheel at 0 degrees and 180 degrees - any play here - this means the shock turntable needs to be replaced or the wheel bearings needs adjusting. Testing a tire by jacking it up and motoring while measuring the rubber tire smoothness will NOT work. That's how to troubleshoot the front end. In this particular case - I bet it's the rear tires not being balanced. joliett There is no problem with swapping front and back tires for testing -- the size difference is for handling purposes. I need to add a disclaimer here: on YOUR car there is no problem with swapping the front and backs. When you get into 9" and 10" rims, the offset for the rear will cause the rim to rub the spring on the front strut, so don't tell your buddy, with a 930, that he can swap the rims front to back, 'cause some guy on the net said it was possible. On some cars it is not advisable, but on an S2 which runs 7" rims in the front and 8" rims in the back, you will both clear the caliper and clear the spring. As for the cost of new tires, it sucks to spend that kind of money, but think of it this way -- the tires are the ONLY interface between your car and the road... Tires make the #1 handling difference and will determine if you enjoy driving the car somewhat, or if you're maddly in love with the performance the good engineers at Porsche so thoughtfully provided you in such an economical package -- a used 944 -- and you swear never to drive another car again! (That's roughly what happened to me) :) Good luck! David Matkin wrote: > Many good suggestions - thanks for those. > [quoted text clipped - 49 lines] > >> I have an 84 944 with no shudder in front end up to and over 100 mph. > >> Yokohama tires. Hello group, Ive read many causes, but there is one left: oxidation of the mounting surface on the wheel and brakecenter. This is very easy to check: you will find rust-parts of alloy on both surfaces. Sand them carefully until the original surface is clean, on the wheels it is grooved, so you will not sand it too much. Then apply the correct torque on the bolts Applying the torque to the nuts crosswise, that should take care of vertical adjustment. Then check the shuddering again. This has helped me a lot. Doing this check every other year is sufficient. Tell me if this has helped! Aart > I have this same problem on my 944. > [quoted text clipped - 96 lines] > > >> I have an 84 944 with no shudder in front end up to and over 100 mph. > > >> Yokohama tires. Good point! I change rotors so frequently (once a year) that I didn't think of that. This could also be checked by measuring the runout of the brake caliper with a dial indicator and a pulsating in the brake pedal would also be felt. > Hello group, > [quoted text clipped - 122 lines] > mph. > > > >> Yokohama tires. Err... make that "runout of the brake ROTOR"... the caliper shouldn't have any runout! :) Otherwise you have bigger problems. > Good point! I change rotors so frequently (once a year) that I didn't > think of that. This could also be checked by measuring the runout of [quoted text clipped - 127 lines] > > mph. > > > > >> Yokohama tires. Hi thanks for all of the suggestions. I finally went down the road of new tyres on the front and a new balance on both front and back. The garage noticed that one of the fronts was not perfectly round and also the wheels that I had previously balanced were only balanced on one "side" of the rim. The new garage did a very professional job. The problem has certainly been reduced but it is still there to some extent. My next task is to have the wheel bearings looked at - I think there is some play here - I will sort it eventually. Again thaks for the advice. Dave > Err... make that "runout of the brake ROTOR"... the caliper shouldn't > have any runout! :) Otherwise you have bigger problems. [quoted text clipped - 130 lines] >>> mph. >>>>>>> Yokohama tires. Hi Dave, I'm glad you're making improvements and getting it sorted out. Drive fast! Take chances! > Hi > [quoted text clipped - 146 lines] > >>> mph. > >>>>>>> Yokohama tires. Wheel bearings are very easy to diagnose...my friend does it in a second by placing his foot on the top of the tire - while the car is till on the ground and shakes the wheel with his foot. I still have to jack the car up. BTW, great wheel balance machines - ESPECIALLY on Porsche rims - put the weights only on the inside of the rim - and none on the outside. My shop (a dumb a.s local alignment shop) says I have to request it. The machine will calculate it from the inside only. If you dont fix the loose bearings VERY SOON - your new tires will definitely follow the course of your old tires...trust me - it happens to me all the time. Signaturejoliett -------- Hi Dave, I'm glad you're making improvements and getting it sorted out. Drive fast! Take chances! David Matkin wrote: > Hi > [quoted text clipped - 179 lines] > >>> mph. > >>>>>>> Yokohama tires. |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2009 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.