I have a 2002 BH comp. I checked out Specialized site and they state my bb size is 73 x 125mm. I am going to get a new one, but it seems the ones I look at (RaceFace Sig. DH 73 x 118or128 - Truvativ GigaPipe DH 73 x 118or128) don't make that size. I will be running a single ring w/ MRP. Do I get the 128 and make up the difference w/ spacers or what?