Hi all hope you can help I have just bought a road bike off eBay and after snapping the chain first time out on it I took it to my local LBS who replaced the chain and rear derailleur and sorted everything out but informed me that the front derailleur wasn't working properly and was caused by the previous owner changing the chainset from a double to a triple without changing a bottom something can't remember what it was he said now does anybody know what this is and is it difficult and/or expensive to change thanks