Comments about iRobot Caster Assembly:

The last review was spot on! I have a dog and 2 cats, and the hair gets caught up in the wheel assembly. As you have to remove it to remove the hair that gets caught up in it, soon the wheel ball is so loose it just falls out. I spent 45 minutes looking for it thinking the cat took off with it, when it was actually pulled in between the cleaning brushes! Very frustrating!

Comments about iRobot Caster Assembly:

Easily the single biggest point of failure, especially for pet owners. Pet hair wraps around the axle, deforming the caster assembly sockets that hold the axle, which causes the wheel assembly to fall out. Every time Roomba transitions from floor to area rug, Roomba halts with an error (and the wheel assembly becomes a cat toy).

Even though this is the same caster assembly that ships with the Roomba models recommended by iRobot for "Pet hair removal," it is the one component that consistently fails because of that task. With two dogs and a cat, a caster assembly will fail about every 90 days. The only way to repair the caster it is to replace it at $6 a pop. (When they're in stock. Which is very rarely. You can occasionally find them at other retailers—for $10 to $20 each). It's also interesting to note that iRobot limits your order quantity to five—even more evidence that this part fails at an unacceptably high rate.

Overall, my experience with my Roombas (I have two) has been an overwhelmingly positive one, except for this accursed caster assembly. It's a shame that an otherwise good experience is marred by repeated failure of one of the least complicated components. iRobot really needs to re-think the caster assembly—certainly for their "pet hair removal" models.