What battle problem is M-85 meant to solve?
M-85 is a special-format Ratchet. It changes blade height, balance and underside exposure and should be tested in complete builds.

Balance
Start with Tricera Press M-85 Bound Spike; it is labelled as a official stock pairing with the note “Takara Tomy BX-44”. There is no second verified build yet, so do not invent one just to fill a deck.
M-85 is a special-format Ratchet. It changes blade height, balance and underside exposure and should be tested in complete builds.
M-85 does not appear in the 20 recent winning decks reviewed by BeyXBuild. That does not make it unusable; it means the site should not call it a tournament-proven staple yet.
M-85 is a special-format Ratchet. It changes blade height, balance and underside exposure and should be tested in complete builds.
Use the stock setup as the baseline, change only M-85, and run at least five launches per side while recording knockouts, bursts, self-knockouts, scraping and spin finishes.
Drop it if it does not beat a specialist in any matchup your other two Beys leave open. Flexibility only matters when it covers a real deck weakness.