Surface type affected distance more than expected
Several groups found that changing from smooth to rough surfaces reduced distance more than changing elastic band count.
Evidence: In side-by-side comparisons, the same car and band setup travelled noticeably less on rougher surfaces, even when groups expected band count to dominate the result.
Rolling resistance and traction changes can absorb energy quickly. If surface isn’t controlled, it can hide or exaggerate design effects.
Try this next: Measure the same car on two surfaces with identical elastic band setup before changing anything else.
early pattern