Any reason to worry about mounting tires that were manufactured 5 years ago, assuming they were never used? From what I understand they have been stored in a basement.

The recommendation is that 6 or 7 years is about it for tires, even if they're new.

http://www.carbibles.com/tyre_bible.html

Thanks. I had always thought it was 6 years from "in-service" date, meaning when it was mounted, but I guess the rubber still degrades when not in use. Will avoid this set.

It really depends how it was stored. If the rubber looks fresh then I'd hit it.

Yea, it's been said that after 5 years the oils in the rubber start to leave the rubber and it starts to dry rot. I would check the tire, inside and out and see if it shows any signs of drying. If not, rock it on the ride. I put on a 6 years old Goodyear that was new but sat in my basement for that long. I put it on the rear of my Conquest and it was fine.