I have raced on one of them and it handled my 100 kg no problems, even with a fast A grade motor pace event, and a standing start wheelrace.
One of the Avanti or Hillbrick bikes would cope quite easy, even some of the older steel framed ones would handle fine, as they all pretty much have heavy duty wheels.
The bike hire is the same fee as the normal track fee, basically free bike but you pay for the usage of the track.