Not seeing a need for 2 pit tables. Why can't all pit characteristics be in the same table? Pit type values would be the (autonumber) PK field of tblPitTypes. A query with tblPits and tblPitType would return Description field data (descriptive text) from tblPitTypes. I think more info is required to suggest how to relate sub types to types but likely the same approach would be the way to go. Do you have type and sub type tables?
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.