SLX 507 Design LabBest for: Outdoor, rough, or inconsistent terrain like gravel, grass, dirt, etc. when paired with a mountain bike style tire (knobby, wide). Or, active lifestyle where a larger profile tire benefits you, like when using a E Assist device on your wheelchair, or if you simply prefer a larger profile tire to absorb rough terrain when paired with a large profile road bike style tire (minimal or no tread). More info: The Spinergy 507mm wheel is