Thank you for getting back to us.
I might be reading your post wrong😀, but the tire s off your Chevy would have been okay in place of buying new tires. But, those tires may be too old. Tires do age.
That is correct for the LT245/70R17 E’s they have a 119 load index (dually is different)
The LT245/75R17 E’s are the 121’s, so you are good…
As far as running used snow tires? If they are 10 years old by industrial standard they are unsafe, but I would not run them much past the 7 year mark, now, down here in middle TN our snow days are wayyyyy different then y’all’s… lol… So about the only time I ever install/deal with snow tires is when a customer is going to be traveling up north in the winter for whatever reason…
Matter a fact, when you northern guys move down here with y’all’s spare set of snow wheels/tires and want them installed come winter time, we just laugh, (saw that a lot when BS moved FS corp from Chicago down to Nashville), I have lived hear all my life and driven in every snow fall we have had since 1986 and never run snow tires… But the most snow I can remember driving in was 9", so we don’t get what y’all get up north… I remember a guy every winter after moving down here, had us install his studded snow tires on his 1986ish T-bird every winter, and most of the time we only had snow on the ground for a max of 2 weeks all winter…
You northern guys can battle it out over the use of used snow tires… 
Thanks guys. I appreciate all the feedback. This has been a learning experience for me.
The Motomasters are two years old, and while they’re probably ideal for sloppy snow, they won’t have as much traction at -20. I wasn’t planning on getting rid of the old Chevy, but an impatient driver who didn’t like our rural two-lane decided that safety wasn’t a priority and took a 45 from behind the person he was tailgating. It was early April and I hadn’t switched to the all seasons yet. We survived because I swerved to avoid, but we rolled down a ditch and up a bank.
I’ve been meaning to get a dash cam ever since. Not sure if I would have wanted the footage of the crash, but that guy’s license plate would be invaluable.
Explain please, in Florida that would mean a 45 caliber pistol!
Oh, haha, handguns are illegal here without a special permit.
He took the most insane 45 degree turn into oncoming traffic that I have ever witnessed, and unfortunately much too close. Most people would peek into the opposing lane.
Reduced load-carrying capacity
Compromised handling/roadholding
Possible blowouts from excessive flexing of the tire sidewalls
I don’t understand what all the hand wringing is about. If I discovered some place put the wrong tires on my vehicle, I would be back there the same day insisting they made it right, not trying to find a way to rationalize keeping them or second guessing the manufacturers specifications…
+1
What that tire dealer did is unethical, dangerous, and a violation of the policies of every tire manufacturer. While I suggest that the OP should keep things “civil”, he should make it clear to that tire dealer that he wants the correct tires installed on his vehicle.
If the people at the dealership refuse his request, then I strongly suggest that the OP should contact the following agency, and file a complaint with them:
The tire dealer already called him, they are going to install the correct tires at their expense.
I suspect whomever sold and whomever installed the tires are looking for new jobs.
I am sure it was either an education/proper training on tires issue, new guy closing by himself and saw a tire sale, or not paying attention or whatever, and yes it must be taken care of asap…
I suspect the OP was wanting to understand the issue. He didn’t realize that passenger car tires have to be derated 10% when used on trucks and he also didn’t realize that truck manufacturers specify tires with load carrying capacities such that there is a reserve capacity that is not supposed to be used. That’s called good engineering.