What is the purpose of grooving the tires? Is it to recut the treads once they are worn down?

There is quite a few reasons for grooving tires. Cleaning up worn treads or deepening the tread void helps with getting more use from the tire. You can also add more thread voids to help the tire flex and grab rocks better. Making the tread voids larger helps the tread clean out (mud, snow,water). Also siping can be done which looks like little razor cuts across thread spaced closely around the tire, which helps cool down the tire as well as helping the tire grip on smooth surfaces (ice, concrete, pavement).

I hope that helps

Thanks for the explanation. Cheers

I thought it was to lighten them up 15-20 lbs a corner like on my 44" boggers. Much easier to do a tire rotation now.

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