Clause 7.2.1. The Toboggan’s Sliding Surface must be comprised entirely of concrete.
Is there a minimum clearance for non-concrete materials, such as the bracing that supports the concrete running surface?
There is no minimum clearance defined in the rules. It is up to the discretion of each Team to design their Toboggan’s Superstructure and Skis without violating this rule. For more information on how this rule is qualified please refer to Definition 2.29.