Tires: Goodyear LT275/65 R18 on 2500 Avalanche, goodyear wrangler, eagle wheels

Question
I have a 2002 2500 Avalanche with with after-market 18" EAGLE wheels and Goodyear Wrangler LT275/65 R18 123/120S Load range E MKB9 BXWV 3803 USED-NA on front and 113/110S Load range C MKB9 LRWV 4003 USED-NA on back. These have about 45k miles on them and appear about 50%. Three questions: 1-is speed rating S? 2-what does USED NA mean? I've not seen this hot-stamped on a tire before. 3-a radial crack up to 1/8" wide by 6"long about 3" in from the tread exists on the inside of one of the front tires -cord is visible in crack, but not torn --- some slight side wall lateral runout is visible when running truck in gear on a hoist. Any insight appreciated.

Answer
Jon,

1-is speed rating S?

Yes

2-what does USED NA mean? I've not seen this hot-stamped on a tire before.

This means the tires were sold as used tires and do not have any warranty.

3-a radial crack up to 1/8" wide by 6"long about 3" in from the tread exists on the inside of one of the front tires -cord is visible in crack, but not torn --- some slight side wall lateral runout is visible when running truck in gear on a hoist.

This tire should be replaced ASAP - meaning in the next few days.  Any time you see fabric, this is a bad sign.