What are the advantages going with aftermarket steel sprockets vs stock OEM? Just purchased a 1st Gen that is geared 16 front, I believe 43 rear. I want to go back to stock 17/39 gearing. Looking to replace my sprockets and chain shortly. Seems like everyone goes aftermarket sprockets. Just want to know why stock OEM aren't used more often? Just going to be using the bike on the street to commute and blast around, so no track use here. Any insight would be helpful.