Lightweight and strong 7075 aluminium road racing drop handlebar for oversized 318 mm clamp diameter 7075 aluminium is a high strength aluminium alloy commonly used in the aircraft industry making it the ideal choice to produce this lightweight strong and rigid handlebar oversized 318 mm clamp diameter reduces unwanted flex under high load by increasing strength and rigidity for further rigidity the 318 mm diameter is carried across the top of the bar keeping the strength where it is