If you keep the weight divisions as they are, then weigh
only the rider, not the tack or water bottles etc. This makes sense to me as
mountain bike racers do not weigh their bikes, & many have different makes
& models of bikes.
Otherwise if you add more divisions & keep weighing the
tack etc… Since the very small people already have even an extra division in their
favor (Featherweight, not just Lightweight), it is only fair to the heavyweights
to add the Super Heavy Weight division. This would probably be 210, 220 or over
for that division. MHO