Your numbers didn't seem right, so I just double checked your math, your life calculation is incorrect, I get 13,324 hours, which is much better. You are still below the recommended loading to prevent skidding, but not as much as I thought when looking at your number, so that might work ok provided you took into account all the forces on it. If your loading numbers are correct, a 607 bearing would be better, that would put you a bit over the 10% loading recommendation.