i have a single-speed mtb that i also use for commuting and i would like to get a better lock for it. i have a cheesy generic u-lock that is about 6"x11" and it's just too bulky. it's old, i don't even know who made it, and it has a round-key lock. i have not figured out how to crack it with a pen, but it's probably not that hard.

i would love to convenience of a "mini" u-lock but i am not sure if it will lock my bike to anything. i don't have any quick-release bolts on my bike, so i just need to be able to lock it to a pole or something. will one of those little 3.5"x5.5" locks work on anything or are those made for road bikes?

I can't speak from personal experience; however, from observing others, I'd say it's important to also remember what you're locking it to. In Boston we're SOL for spaces at the bike rack very often, and when you do find one it's often one of those really thick ones that no habla mini-U-lock. I'd be out of luck more often than not if I used a mini-U.

I use a Mini Onguard. However, they do require more thinking when locking, due to the smaller size.

I'd say you want the smallest U-lock that will fit through your rear triangle and around what you want to lock it to.

There are no bike racks around here; even with a full size Onguard U lock, I've had to get creative with locking techniques (suspending the bike 3 feet in the air, or propping it vertically, among others) to attach it to a fixed object.

I use my Kryptonite Evolution Mini just about everywhere I go. I use either Sheldon's technique (around rear wheel only, in between the stays) or Sheldon's + seat-tube.

+1. I really want one of those. I've heard nothing but great things about them. But they're pricey... and yeah, I know the "don't buy a cheap lock" thing, but i have an on guard cable and longer U-lock already.