Double is probably a stretch but I was comparing the stock tires to those that typically get put on. The stock front 27” Big Horn tires on a Pioneer 1000 weigh 22# in a 6 ply rated, but the stock tires are only 4 ply so probably a little lighter. 12” tires are heavier than 14” due to the 14” shorter sidewall and 15“ in the same diameter are likewise lighter than 14” for the same reason. But the weight is pushed further out from a rotational standpoint so the physics of a larger tire can’t just be looked at from a dead weight standpoint. Comparing 8 ply rated ATV to 4 or 6 ply rated LT also results in a lessor weight difference, plus the ATV tires always have a deeper tread depth, sometimes over double. Probably the biggest difference is the air pressure. ATV tires are designed to work at much lower air pressures than LT tires, plus the wheels for ATV are likewise rated for lower pressures. LT tires normally give their best performance and mileage, on a truck, at the maximum rated PSI. Running them at the recommended PSI for a Pioneer could result in failure due to excessive heat buildup. Dealers tell me that customers running LT tires on their RZRs have more repair issues, but that usually means the customer also went to lift kits and larger tires so maybe the LT tires aren’t the only issue. Personally, when a customer tells me they are only using their machine on the street, I recommend putting passenger car all season tires on them, not LT. I know on my Pioneer 1000, when I went to 28x10r14 deep lug 8 ply rated tires, the acceleration was affected as well as top speed, about 60 mph. BFG is one manufacturer that makes both ATV and LT tires and they claim much better performance on ATVs/SxS running the proper tires.