For my 2001 C10, am I truly safe to go with a 110/80/18 tire for my front, riding solo and especially with a passenger, over pot holes, tight leaned turns, etc? I understand it is not the OEM size but many riders such as yourself use them with no issues... I always shy away from making any such non-OEM size changes to my tires.
Yes, mine is an '89 so I have the older narrower rim, but I have ridden several 94-06 C10s fitted with the 110/80 front and they ride just like my '89.
The 110/80 tyre is actually a better fit on the later 3" wide rim than the 120/70 is.
As for the defective Avons, I have heard lots of instances in the USA, but very few here in the UK or EU.
I'm not sure, but since Avon are owned by Cooper Tire & Rubber, chances are that their Motorcycle tyres are made in the USA or Mexico for the US market.