The Coolest Dork in town.

If I were going to use one with a freewheel, I'd go on ebay and pick up a nice old steel one.

It will last forever, and most people will have never seen one before.

John

That does look cool, I'll give you that. But the drivetrain on this bike is solid and nothing needs to be replaced, I bought it from the original owner and it didn't look like he used it much, bike was immaculate.

A nice polished metal disk on a vintage bike, or a vintage metal disk on a more modern bike can look good.
A brittle, yellow plastic thing should be hit with a hammer in to little pieces and tossed in the trash.

The last time my rear derailleur went to spokes was when a stick got tangled in the spokes, chain, and or derailleur. The disk did not help.

I've never run a dork disk and no one I ride with does either. BUT. On a long group ride I came upon a friend with her chain jammed behind her cassette. She was climbing a steep hill and something went wrong. Neither of us could free it. Looked impossible w/o a cassette lockring tool and wrenches. So, call of shame. It happens that the sag driver is now her boyfriend, so not all bad that day. Made me think again about that disk, but I didn't go home and put one one, either. So far, so good. It's one of those things: a once in a lifetime accident - she probably has a couple 100 thousand miles behind her - against a few grams of disk. No disk is like saying, "I never make a mistake." So there's that egoism thing to deal with. She didn't put a disk on her bike.

While mountain biking it is possible to get vines, twigs, rocks, sticks, logs, or legs into the drivetrain, and force the chain off the largest sprocket into the spoke side, even if the derailleur limit screw is properly adjusted. This rarely happens though. Still, I do think this vulnerability exists and represents a place for improvement. I have no ideas for a remedy. Dork disks are probably not going to be an acceptable solution for the present market. Maybe super light carbon fiber integral dork discs?

I'm fairly certain that some of the old equipment I used to ride on had rear derailleurs with springs inside the limit set-screws which are supposed to help prevent them from backing-out and falling out of adjustment. This may have been the cause of some bad chain drops. The intense vibrations of hard-tail mountain biking can be extreme.

Thread locking compounds are really essential.

Interestingly, Campagnolo 12 sp cassettes have a little lip for hub protection.

https://cimg1.ibsrv.net/gimg/bikefor...1d5482643a.png
https://cimg4.ibsrv.net/gimg/bikefor...2911d4cc18.png

I've had/have a buncha bikes. I don't feel the need for a dorkdisk on any of the road bikes but every one of the past and current (both dualies) MTB's have the plastic on them and I feel no shame.

I think it depends on the quality of the components. If you are using a older dept store bike then you probably should have a dork disk.