Are the “big” wheels on the SP interchangeable (SP only)?
Yup; you can mount them on either the front or the rear of the chair. In specific situations you may find the need to mount them on the front OR the rear. For instance, in the case in which a toilet has a narrow-depth tank and the 20″-wheels hit the wall behind them, the toilet seat hole of the chair may be offset from the seat hole of the toilet. This may result in an, obviously, undesirable result in which somebody will be cleaning up the floor.
