I know this is outrageously illegal, but I've done minor alterations to MFB F and HF bottoms. I've been able to use rounded and cylindrical poly-caps from Gundam and Super Robot Wars kits to protect my tips. I'm currently lacking a beystadium so I try my hardest to protect my bottoms.
The Polyethylene bits don't last long, but they still allow the the tops to spin freely, more or less. The cylinders act as RF and the rounded ones act as B or WB.
The most interesting by far, is the bearing tip I just came up with! I cut the jack plug from a cell phone charger and fed it through my HF. It's a snug connection and did not at all damage the bottom.
The Polyethylene bits don't last long, but they still allow the the tops to spin freely, more or less. The cylinders act as RF and the rounded ones act as B or WB.
The most interesting by far, is the bearing tip I just came up with! I cut the jack plug from a cell phone charger and fed it through my HF. It's a snug connection and did not at all damage the bottom.