Dura Ace NJS & BIA Track Cranks Vintage. NJS Dura Ace 51t chainring. Perfect for vintage track or old school bmx. The item "Dura Ace NJS & BIA Track Cranks Vintage Old Scool Bmx Velodrome" is in sale since Friday, May 18, 2018. This item is in the category "Sporting Goods\Cycling\Bicycle Components & Parts\Bottom Brackets". The seller is "mickhardyguitars" and is located in Maddington, WA. This item can be shipped worldwide.