Single wheel tests are commonly done in the early design phase of small planetary exploration rovers to predict the rover’s overall mobility performance. This research explores the correlation between single wheel and full rover mobility experimentally. A key contribution is novel single wheel experimentation on inclined terrain. These experiments provide a conceptual bridge between single wheel tests on flat terrain and full rover tests on sloped terrain. Single wheel experimental data from sloped and flat terrain is used to estimate the slip ratio required for the rover to climb terrain inclined at a specific angle. The rover is predicted to climb a slope of 15 degrees with approximately 0.45 wheel slip ratio based on flat terrain data or with 0.6 wheel slip based on sloped terrain data. In fact, full rover experiments exhibit 0.8 slip, demonstrating that single wheel experiments underestimate wheel slip by approximately 0.35 (i.e. almost half of 0.8) in flat ground tests and by 0.2 (i.e. a quarter of the actual value) on sloped terrain. Due to such disparities, predictions of full rover slope climbing ability based on single wheel tests should include additional factors of safety.