Most of the tire hum/singing/noise comes from the side lugs and very few modern mud tires have side lugs sticking out past the carcass. The Buckshot Mudders and Super Swampers of my youth had large side lugs and made a LOT of noise on the road. They pulled really well in the mud, which was what we needed them to do. Noise was secondary to traction.
A modern Buckshot Mudder:
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I am running 33x12.50-15s on my '87. The Cooper Discoverer STT PRO was my tire of choice but I was actually looking for a tire that would "sing" on the highway. I am looking for any way I can duplicate the experience of driving one of these old trucks the way I did back in the '80s. Sadly, the Coopers don't make as much noise as I wanted, they are pretty quiet so far.
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We are running a set of the BFG Mud Terrains on the Bronco and they are much quieter than you would expect. Again, the side lugs don't extend past the carcass and that keeps things quiet.
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