Needle bearings are not designed for side loads (movement along the shaft axis). Ball bearings are better for that. With the low weight of a mower it's likely OK for needle or ball. However, the bronze bushings are probably best of all. Normally they are sintered (made from powder) so that means there is a lot of space in the bushing to absorb lubricant. Some even have felt washers on the ends to act like oil reservoirs to supply the bushing. Seals that prevent water or contamination entering adds further reliability. I have an HRN216, hoping it continues to glide ...