Dork disc = Plastic shield between cassette and spokes
The following photo showed-up on a recent Facebook Marketplace ad, and aside from being astounded as to how large the "dork disc" is, I can't help but wonder why bicycle manufacturers still put them on new bicycles? (The bike in the photo is obviously not new, but I'm pretty sure new bikes still have dork discs.)
Back in the 1980s when my bicycles had non-indexed downtube shifters, it was quite possible to over-shift the high gear and potentially push the chain into the spokes if the derailleurs high limit screw wasn't set quite right. However, it's now nearly 2025 and I can't remember the last time any bicycle I've owned over the past few decades has had an issue that a dork disc might help prevent. If the rear derailleurs high limit screw is set correctly, the odds of having a chain / spoke issue is nearly non-existent. So why do dork discs still exist? To keep chain lube off the spokes?!??!