Molecular magnetic wheels are models systems for the study of quantum coherence, finite-size effects and have been proposed as possible candidates for quantum bits. While AF polymetallic wheels are relatively common, ferromagnetic examples are much rarer. Recently a family of Cr(III) wheels has been reported showing a remarkable dependence of the magnetic behavior on the nature of the intermetallic ligands. We propose to perform an INS experiment on one Cr10 cluster of the family which shows an anusaul S=9 ferrimagnetic ground state to directly determine the Cr-Cr magnetic interactions. This molecule is one of the largest that can be successfuy deposited by UHV on different single-crystal substrates preserving its integrity, which is an important step towards the development of nano-devices for high density information storage and processing.