Neither Tyrepower not Yokahama say they are LT construction from what I can see. OP wanted an LT.
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There are 2 options in this size - 110H & 119S. The 119 is an LT tyre. Can check when I get home later in the week but pretty sure its on the tyre.
YOKOHAMA GEOLANDAR AT G015 LT 265/60R18 119S Tyres | Tyresales
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I'm running a set of these on my 18" wheels (LT265/65/18). LT Construction and are a hydrid MT. So, in theory they should go well in mud and I can attest that they behave on the road due to their tighter tread blocks in the middle of the tyre. I've only ever had them on sand and I found them really good on my RRS .... once I got used to the grunt the RRS has compared to the Disco that I'd previously owned. Meaning .... deep, heavy (wet sand) almost got me bogged when I gave it a bit too much welly! LOL!
They clearly are not going to be as quiet as the tyres your car came on and will not handle as well, but good luck finding a fatter ATR/AT/MT that does.
They are pretty inexpensive too and have some good international write-ups. I honestly can't say what their wear will be like, as I only fit them when planning a camping trip. Anyway ... something to research.
Cheers,
Kev.