I bought a key-based bike lock, but after I was riding a few months, an odd thing happened: I came upon a combination bike lock from Kryptonite which someone had left behind, unlocked, on a guardrail. I made some attempt to find the original owner but unsurprisingly there was no way to do so, so I kept it. I like the combo lock better than a key because I don't want to have to carry the key while I'm biking: things in my pocket can get uncomfortable. And it's a more solid lock anyway (not exactly the one pictured but close).
When I put my bike away for the year when the snow started to fly last November, I didn't think to write down the combination anywhere. And since I didn't buy the cable myself, I never registered it with Kryptonite. So getting my bike out this year, I saw it, and... can't for the life of me remember the combination. Argh.
While watching TV and doing other things, I held the cable in my hands with a gentle pressure and ticked my way through combinations... all 10,000 of them, about two a second. But no luck. The tumblers are finicky; even when you're on the right combination it might need a little shimmying to get it out. I couldn't do the shimmy on every one of the 10,000 combinations at two a second, so I no doubt went right past the right combination and kept going.
It seems like there must be a way to figure out the combination, given adequate time and access to tools, but I can't think of it. Short of an X-ray machine or sonogram, that is, and even if that would work I don't know anyone who has access to one. I tried to listen to the tumblers as they clicked to see if I could hear them falling into place, but no such luck. And there's just nothing to feel in this design, at least not one tumbler at a time. I'm a clever lad, how come I can't think of anything?