According to one aspect, a suspended mounting bridge is used to attach a nuclear magnetic resonance (NMR) instrument assembly including shim coils and/or an NMR probe to an NMR magnet cryostat. The mounting bridge is suspended across a central region of an end cover (e.g. bottom plate) of the cryostat. Consequently, flexing of the end cover center in response to changes in environmental pressure does not cause displacement of the shim coils and/or RF coils relative to the NMR magnet center. The mounting bridge may be attached to a peripheral region of the end cover (e.g. along its perimeter), and/or to a cryostat side wall. The mounting bridge may be shaped as a quasi-rectangular strip or may include multiple spokes.