im building up a new bike, all brand new parts, chain is loose 270 deg of rotation then bam! tight as a monkey's ass, i have a sugino75 crank,sugino 48 chainring and new izumi V chain. i tried loosening the chainring bolts to rotate the ring slightly , that did nothing so i removed the ring and indexed 180 deg on the spyder, still not solving the problem WTF??? can it be that this ring is not true???