Recently, I had a nail in the sidewall of one of my tires that required a new tire. Discount tire had suggested that I get 4 brand new tires because the tread depth would be too different from the other three. I ended up going for just the one replacement tire since the 3 tires only had 10,000 miles.

The 3 good tires had tread depth of 9/32 and the new tire was 12/32. Has anyone done the same? Replaced a single tire that had more or less difference? The reason why I'm asking is that I was told that in 4x4 I could damage the truck because the wheels would spin at different rates.

 

I've done it. In this case, your only talking 3/32. No biggie. I would have had the new tire mounted on the right rear.

 

I hate to have mismatched tires, but I'm OCD. I've been I that situation. If you had more miles on the tires, I could see replacing them all. With 10,000, I think Discount Tire is trying to make a sale. Nothing against Discount Tire, Its the only place I've bought tires for the last 25 years.

 

As tires wear, it is not uncommon for them to be 1 -3/32nds different. This is a non-issue.

 

I also would not worry about it, not one bit. If the other tires were 1/2 gone, I'd start being concerned. Put it on the right rear and do a few burnouts if it makes you feel better

 

Mount it on the right rear.

If you have the 2.7 EB a few extra hard launches and all will be good.

Most modern F150's are running open differentials and then only lock up with the E-Locker option to be used off road.

Every time you turn ALL your tires turn at a different rate.
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19 F150 max tow (4) 20" wheels with a factory supplied 18" spare.

 

At most they could have suggested 2 tires, not all 4. That's excessive. At your mileage they didn't need to even offer 2 tires.
You made the right call getting just 1. The only thing I'd have done was use it as an excuse for a new tire setup.

 

This right here. At most I would have replaced both rears and now you have a really good non mounted spare sitting in your garage but with only 10K miles on a probably 50K mile or better tire just replacing the one would be fine in my opinion as well.

 

My daughter had the same issue with walcrap, until she showed me the receipt. She had the full extra warranty. Then they would only replace the one tire. I told them no you said all the tires had to be replaced. We went round and round. They gave her a $200 give card and she kept her warranty on all the tires. Don't think they liked me making such a fuss with a lobby full of customers waiting to buy tires. It was the last time any of our family bought any tires from them. I avoid them at all cost for anything after this. I would not worry about only 2/32's. i Have done it in the past.

 

I had this happen on my current Falken Wildpeaks after only about 5k miles. Ended up happening on a Sunday and the only tire I could get my hands on before a large road trip was some kind of Goodyear at Sam's Club. The tread wasn't terribly different, it held air (still holds today) and I ran where the damage occurred for a while (Left Front) but next rotation I crossed the fronts and put on the right rear and has been there every since. I haven't rotated in about 20K miles and they are wearing perfectly and no issues at all (25K on the old Falken, 20K on the newer Goodyear). I wouldn't worry too much about it.