My rotors on the front have looped, metal, heavy gauge wires jammed into a couple of the fins/vents on each one. What is the purpose of these, and could they be a contributing cause to vibration at high speeds (80 or above), causing the steering wheel to shake very noticeably? I know I need new tires, but I do not know what these wires are for, or whether they even belong. They are jammed pretty firmly in the vents.

 

those are balancing weights Ed,
if your old rotors are really rusty and you have a shimmy,
swapping in a fresh set of hi quality rotors will restore the balance.
I suggest you get a new set of Zimmerman Z coated rotors and a new set of Hawk Pads when your done it will look like this

 

interest to hear what they are there for, confirm i had the same but 1 had rusted so much it was bit loose so i pulled it out, did't want it coming out at speed

 

these are put in from the inside of the rotor so they wont come out when the rotors is spinning

 

Thanks Stan. I probably should get new rotors when I do the tires, as the shimmey was pretty hard at speed, and that is where I like to drive - at speed!

 

Ed your at home, give the vendors and delivery drivers something to do ORDER NEW PARTS

 

I never even heard of such a thing. Learn something new every day.

 

For years I chased a vibration and wound up replacing everything over the years and it was the rotors even took front wheels to rim people wondering if I had a bent wheel but those are fine...the old rotors were way out of balance and were shaking the car like crazy 85mph and above.

 

Yes, put new rotors Ed.
BTW, never seen those balancing weights inside rotors...

 

Some years ago a guy working for ATE told me that only the cheap aftermarket brake discs are balanced with steel inserts (like in the pics of the OP).
These inserts, over time, inadvertently rust (lose weight) and eventually fly off, leaving the disk out of balance .

On quality parts (Porsche and e.g. Zimmermann) you will find "flats" ground into the perimeter between the surfaces of the discs for balancing. These obviously cant get lost.

In short, his message was: stay clear of discs balanced by steel inserts as you can expect them to low quality in other ways, too.

FWIW

Kurt
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90 S4 satin black metallic
OC Charter Member