Just picked up a new to me 2020 model x LR+. The rears have visible steel visible on the inner sidewalls so I know I should replace them. Front tires look great still (and I don't believe suffer from same wear issues as rears, right?). But while looking around I noticed the fronts are also 275/45R20. I know the previous owner had the tires changed previously. I'm not sure if what he did was "safe"?