style="font-variant:small-caps;">ghalo</span>]{}simulation [@stadel_ghalo_2009]) analyzed by a variety of subhalo finders. They suggested that subhalo spins are significantly offset to lower values than those seen in typical distribution functions fitted to [haloes]{} [@bullock_2001; @bett_2007]. As this result is independent of the subhalo finder used, it suggests that this is a true physical effect. This could not be investigated further because their resimulation did not contain a large field halo population. Excluding sub[haloes]{}, @colin_2004 found the spin parameter distribution of isolated dwarf dark matter [haloes]{} to be perfectly consistent with that of larger [haloes]{}. This suggests that the consistently lower spin of substructure is not due to the generally smaller mass of sub[haloes]{}, but is more likely related to tidal stripping of high angular momentum material. On the other hand, this offset could also be due to differences between the Aquarius and [<span style="font-variant:small-caps;">ghalo</span>]{} simulations and those used by Bullock to define the field relation. To answer this question we require a single simulation that simultaneously includes both a significant subhalo and field halo population.

In this work we use purpose built simulations, specifically designed to contain both a field and subhalo population, to investigate the difference in spin distribution functions between sub[haloes]{} 