While changing my bike chain, I noticed letters stamped on some of the links. The old chain (Shimano CN-HG53) has »OG« stamped on some links, while the new one (Shimano CN-HG93) has »RL«. Google doesn't find anything useful. Anyone knows what it means?



The RL and OG might be date codes. Assuming these are 2 different chains, RL would denote 1993-December and and OG would denote 1990-July. If you think they are newer than that, the chart isn't up to date, but if you follow the pattern, RL could be 2019-December and OG could be 2016-July. The second set of dates makes a lot more sense based on what I can see visually from picture.

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    Plausible. I have two HG701 chains on current generation Ultegra groups. One is marked RD, and the other RE. Both were purchased in 2019 or 2020. – Weiwen Ng Jun 20 '20 at 14:37
  • Bought the bike used in 2017, with a new chain (the »old one«) put on by the shop. Got the »new one« from amazon a few weeks ago, so it all checks out perfectly. – MaxD Jun 20 '20 at 14:51
  • Does age of chain matter at all if both are new/unused? This might be more for stock control, to clear older packaging etc. – Criggie Jun 20 '20 at 22:50

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