OT: rough-riding kumhos? - follow up

[amalventano at sc.rr.com (Allyn)]

ok, did some swapping tonight:

instead of jetta, borrowed wheels from the rocco-trailer. 14" teardrops with random tires. dont even have wheel-weights on them for some reason. but hey, im troubleshooting, so what the heck, i'll give it a shot.

throw em on, go for drive, vibration GONE (well, except for the tiny vibration due to the 14's not being balanced).

get back home, throw the original front wheels on the spare rear axle beam i have, so i can spin/examine them. get this, the right front kumho has this funky 'dip' in it. over about a 5-8" span, the entire tread area dips by about 2mm. even the center tread groove follows this dip. also, while the center is dipping, the sidewalls stay where they should be (i was thinking it was the wheel, as this wheel has been straightened twice, but the wheels/sidewalls rotate true).

so i throw the wheels back on - *backwards* (on purpose), jump back on the highway, and the once annoying vibration turned into an obnoxious vibration. it had moved directly below my feet (now left front), and was so bad in fact that my teeth would chatter if i let them, and i had a rather nice back massage after a mere 10 minutes on the highway.

o well, time to get those 235's instead of the 215's that are on there now anyways.
more to follow...
Al

  ----- Original Message ----- 
  From: jesse Neufeld 
  To: amalventano@sc.rr.com ; scirocco-l@scirocco.org 
  Sent: Thursday, June 12, 2003 1:42 AM
  Subject: Re: OT: rough-riding kumhos?


  iam gonna have to agree with bryan about the idea of it being something other than tires since you are not feeling it through your steering wheel.
  ive used Kumho Ecsta 712's on my scirocco for a little while and i did notice i always had vibration that would dissapear if i put my 13's on.. i did get the rims with that had the kumhos on balanced but they always still had a slight vibration no matter what. my balancing job wasnt the greatest tho and my rims could be also part of the problem..

  if anything i would do what you said and swap a set of wheels and tires on there from a car that has no vibrations(your jetta iam guessing since you mentioned it) and compare the 2 cars now that the rims are swapped.. hope that helps 
  -Jesse





  --------------------
  -84 Scirocco
  -86 Golf
  Kelowna, BC


  >From: "Allyn" 
  >To: "scirocco list" 
  >Subject: OT: rough-riding kumhos? 
  >Date: Thu, 12 Jun 2003 00:57:38 -0400 
  > 
  >has anyone had any ride issues with kumhos (or any vibration issue that 
  >ended up being tires - any brand of tires?). 





         
Just helping you brainstorm here. Since you said you don't feel it in the 
steering wheel, that would suggest to me that it is not your front tires/wheels.  
Possibly your rear tires, check the tread wear to see if you see any uneven 
wear on the rear tires.  Vibration amplified by acceleration = more wheight 
transfer on the rear wheels maybe causing extra vibrations.  Then agian this may 
also suggest an engine not aligned properly or a failed engine mount  when the 
engine moves as you apply power it makes contact with something causing the 
vibrations.  I'm going to go with the later.

Brian 86 16v
98 Jetta GLX Vr6
 



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