Review on 🚲 Shimano BSA Bottom Bracket (BB-MT800) for SLX and Deore XT by Josh Goldsmith

I just installed this bottom bracket on my bike with RaceFace Affect cranks so I can't comment on the performance. However, the setup was complicated by the bike industry's penchant for dumb standard changes. The new style cups on this bottom bracket are smaller in diameter than what is considered standard for BSA male cups, so they cannot accept standard tools. Shimano includes a plastic adapter, but it was disposable at best. I had to hammer the adapter into the Park BBT-19.2's cup with a rubber mallet, which cut the plastic off the adapter. I then had to drive the tool into the BB cup on each side, cutting off more plastic as I did. Despite the tight fit, I still managed to slip it off one side when tightening. If you want the right tool you'll have to shell out another $20 for a Shimano TL-FC37, which is annoying as you now need two tools: one to remove the old style cups and one to install the new style cups. Because of this issue, I'll likely be looking at other brands for my next BB replacement.