Re Astra Wheel bearing post - NickS
After driving for a bit longer and listening to the suspect throbbing sound coming form what i thought was the bearing i have now realised it sound s as if it is actually coming from the Joint that drives the front wheel (CV joint?) a mate has told me that if it has gone it will knock when on full lock but it dosnt, so any ideas what it could be boys?
Re Astra Wheel bearing post - Keith S
Did you try what I recommended?

Doubt it is a CV joint, especially if the boot is ok.