I bent my 30 tooth chainring ,and it needs replaced. I have been unable to find any chainrings that say they will fit 5 bolt truvativ isoflow cranks . I have measured the bcs and it seem to be 94mm . My center to center measurement is 74mm . The chainrings on my bike now are 52-42-30 , and I would like to keep that ratio . If I change my ratio I think I would need a new chain. I'm not real good with the metric system so I'm not sure of my measurements , as in am I using the right measurement [MM, CM ]the numbers are right Jjust not sure if I'm using the right metriic terms.