[svx_commuter]

Rotors warp from uneven heating. The rotor heats up when the brake is applied. A quick hard jab on the brake will only heat half the rotor. Presto- Chango warped rotor. If done properly in the rain it will warp real bad.

I happened to do this on a Honda CRX right after I got new front rotors. It really was upsetting. New rotors and now the car was braking like sh!t. So you know what I did? Several hot speed stops with heavy braking from 60 mph. Heat treating on the car
No more wrap.

Then again it could be the lug nut torque, bad wheel bearings or a loose calipher guide pin or something else.