Besides a disklock, I still use the chain I bought for my R100CS.
The lock that came with the chain once fell on the key and the internals shifted it wouldn't lock again.
So I bought an ABUS disklock, some sort of roundish thing with a pushpin shaped thing that I could stick through the chain, into the roundish thing with the lock.
A few mounth ago I had trouble opening the lock and looked for a new one. These were out of production.
Now I have another disklock that works like a padlock with the U-shape going through the chain.
Although the combination is not ART certified, (the chain was and the lock is) it looks more impressive.
When I want to be sure I also apply the disklock to my front wheel, but I need to get it from under the saddle.
I've wound the chain through my topbox-rack (where my gloves are).
With the chain I can secure my bike to fixed objects, so the bike can't be lifted into a truck.
