I am looking for a low cost compact crank to replace a Shimano 105 Hollowtech with a BB-5500 bottom bracket (68 - BC1.37x24 - 109.5). Will an ISIS compatible crank fit? My existing BB could probably due with replacing. Am I better off up upgrading the bottom bracket? There don't appear to be a lot of compact cranks that are compatible with the BB-5500. Thanks!