I'm converting my Trek 520 to a single speed and want to replace the current triple crankset (which has an integrated bottom bracket) with a Sugino Messenger crankset and accompanying square taper bottom bracket. My question is how do I determine which spindle length I should be using? The BB on my Trek 520 looks to be wider than other road bikes I have seen. Prior to swapping to a different triple crankset, I used to have a BB with a 118.5 length spindle I believe -- but this would only be appropriate for a triple crank, correct? If anyone can help with how to measure/determine what spindle length I need for a square taper bottom bracket that would be used for a single speed on my Trek 520 it would be great. Or conversely if you just happen to know the length that would be great too!
Thanks in advance.