Cannondale Synapse serial number
I bought a Cannondale Synapse 2nd hand. I have the serial on the Cannondale waranty card which came with the bike, which matches the serial number on the bike. However the serial number on the bike is on a sticker rather than stamped onto the frame. This sticker is on the bottom of the seat tube. This seems a bit strange in that in the event of a theft, it could just be peeled off.
There are some numbers stamped on the bottom bracket shell, but they are obscured by the plastic cable guide. I'm not sure if I should try and loosen the cables (by going up to a high gear and then ratcheting down without turning the pedals) and removing the plastic guide. But I don'tknow if I would end up breaking it.
What is the "correct" serial number I should be using to register with the National Bike Registry and how do I find it?