I have an old Giant OCR with mainly Shimano sora components. It has a Ofmega 'vantage' triple crankset which is well worn and a rear 7 speed cassette. I want to replace either the chain rings or fit a more up to date crank set....It currently has a 5 arm 'spider' with a BCD of 130mm. The square taper BB seems ok....Any ideas on what would be the best options and possible compatibility with the 7 speed cassette? - thanks...
