Whirring Noise from Rear Left side

[Betrivent]

So originally I thought it was coming from my belt., since it only occured after around 3500-4000 rpm. But yesterday I happened to hear it come distinctly form behind me and to my left. Any idea what this could be? Again this ONLY happens at a certain RPM range, but it does NOT sound like it is comign from the front of the car. I'm stumped.

[OTA'sTOY]

possibly the rear hub bearing

[salmonz]

90% positive it is... Had the same on my caravan.

Hub and bearing assy, yaris, w/abs, rear $288/ea US
Hub and bearing assy, yaris, no abs, rear $135/ea US
http://www.trademotion.com/partlocator/index.cfm?action=getJointLocator&siteid=214001

They're a SOB to get off, so I recommend taking it to a shop to get the work done.

[Betrivent]

Ah god damnit. What could have caused this? And is there any other way to repair it?

Would this also cause drag to the left then?

[Betrivent]

Update, so I spoke to a mechanic at work, and he told me that hub bearings can just be tightened. Now I'm wondering if this is the case, are they the bolts mentioned in this picture?http://i40.photobucket.com/albums/e239/fatherdutami/Penguin%20Garage/step03.jpg

The ones in behind the plate are the ones I'm referring to.