Q: Why would my Nissan Maxima make loud humming noise when I accelerate up 55mph but noise stops or gets softer at 60mph.

It sounds like you may also need to change the right front bearing as well. Bearing damage usually happens slowly over the course of days or weeks or maybe even months. You may notice the noise getting louder and louder over 50-100 miles. Make sure you replace a worn bearing quickly, but it may be ok to drive for a few days to verify you have a bearing problem. A worn bearing will generate more heat than a good bearing so you can sometimes find a worn bearing by feeling for heat around your vehicle’s wheels near the lug nuts. If one wheel is significantly hotter than the others, it may have a bad bearing. I would suggest having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.