How do rotors cause vibrations?

[Jesda]

I put in a pair of Duralast rotors on the front, $25 a piece. They braked smoothly but caused terrible vibrations in the steering wheel and through the rest of the car.

This week I got my old OEM ones turned and reinstalled them, and all is well.

How can new rotors cause so much vibration if they still brake smoothly? I know that obviously the problem is that they're cheap, but what specifically is the cause?

[maxnix]

Spin them up and I am sure the imbalance will manifest itself.

Could be made metallurgy, bad QC, bad molds.......

[AZhitman]

Ever buy a bike wheel at Wal-Mart?

Shimmies like a mofo.

Buy a Velocity hoop with Ti spokes and a Nuke-Proof hub and it's solid gold.

[Q45tech]

If you have problems with the rotors what do you think the pads and other replacement components are.......................

[elwesso]

i still think that having OEM rotors turned 2-3 times is better than buying really cheap rotors....

[maxnix]

i still think that having OEM rotors turned 2-3 times is better than buying really cheap rotors....

No doubt a true balanced rotor is better than a new imabalanced one.

[JedCoop]

i still think that having OEM rotors turned 2-3 times is better than buying really cheap rotors....

Agreed. When I had the rotors on my Honda Van turned, the shop did not get them done in time. They gave me new rotors for the same cost as turning my OEM rotors. The cheap rotors lasted about 15K miles before vibrating, so now the OEMs are back on to stay.

[Defiant]

More likely warpage rather than imbalance. A common cause is over- or unevenly-torqued wheel studs.

[Q45tech]

Buy your own personal torque limiting stick and keep handy to loan technican [wheel changer].

I always ask to see the orange stick [tool] before I let any strange person touch the Q.