This could be a 'duh' moment, but... I recently picked up a slightly used thunderstar 21" wheel for my NT. It didn't come with the bearings in so I purchased the installation kit from HD. Problem is, the bearings don't fit. They measure around 50mm x 20mm x 3/4" axle and the wheel only has space for a 45mm +/- wide bearing. I double checked that I have the right kit, so now I am wondering if I have an older wheel.
I just had a new tire installed on the wheel and I would really like to salvage this project... Any ideas?