Customer Reviews
This lock works great... mostly 
2007-09-09
Ok, what's there not to like, fits in my back pocket, comes with like 5 sets of keys, good price, tough steel.. I love this lock. One caveat, the mount does not seem sturdy, so I decided not to install it. The key even has a led light built into it. One other issue is that the plastic on it sometimes loosens up so you need to remember to tighten it back, or it won't lock; this can be frustrating if you don't realize what is causing the lock not to work.
Nice little system! 
2007-06-24
So upon becoming ridiculously attached to my first road bike, I decided to buy a decent locking system. I did a good amount of research and went with this little guy (also keeping funds in mind :)
It's worked great for me thus far. Sometimes I have to be a little picky as far as what I lock it to since it's a mini and the shackle is a bit smaller. However, I follow the Sheldon Brown locking system so I usually have no problem. Then I just loop the security cable through my front tire, then around what I'm locking to and then back to the lock. It's great!
Everything about the lock bracket is true though. It just feels really cheap to me. The last thing I want is to be riding around and have my lock falling off in the middle of a busy street. So I just toss the lock and cable in my bag. I've also put the lock on my frame while I ride and it's worked just as well.
Another thing I've noticed is that the crossbar only locks on the shackle one way. Sometimes I'll go to lock it and the key won't turn. So I just flip the crossbar over and it's fine. Not a big deal.
I definitely recommend this lock! It's perfect for the price. Or at least until you can save up for The Beast or a Kryptonite :)
Great lock 2007-05-13
I bought this lock because regular locks would not fit on our mountain bikes. The area between the crossbars was crowded with a waterbottle. This lock fits very nicely in the small area, and the extra cable is worth its weight in gold. I easily lock up my back tire to a pole and loop the cable through my front tire and the lock. It's a great little system. I also bought a bike seat storage pouch for the cable. It conveniently stores away there.
Many people said the holder was cheap when I read reviews. I don't agree with them. Mine works great and is very secure.
I had one complaint. The lock I received was not the one pictured. Mine has yellow ends on the locking bar. I think the modle number ended in TC, but I believe it is the same lock. It works great.
my lock was different than pictured 
2007-05-13
When I bought the lock and cable, the picture of the dt 5015 was up, but the price was only around 25 total. Turns out that they had the dt 5013 in stock. The lock I got is rated by onguard as 3 + stars for security. I believe the 5015 is rated 4+ stars or something. I felt a little mislead by the false advertising, but I guess I saved a few bucks over the up-to-date pricing. Hopefully, if you order now you'll get the higher rated lock. Regardless, the mini lock size is great for securing your back wheel via the Sheldon Brown method, and the cable lends peace of mind for my quick release front wheel. The mini size supposedly makes it harder for the evil ones to insert cutting tools. I carry the lock in my bag since it's mini sized, so I can't comment on the frame attachment carrier that others felt mixed about. So, even though I got a lower rated lock, I figure anyone willing to take on a U-lock is going to need power tools and no amount of security locks is going to stop someone that determined. For the less than professional thief(outside NYC), the mini-U and cable are very strong theft deterrents.
good tradeoff between security and weight 2006-12-03
pros:
moderate weight: At about two pounds, this might be a lot heaver than your wimpy cable lock, but I think it's well worth the additional deterrence/security.
small size: Just enough to fit around your seat tube and through your rear wheel, which suffices if you subscribe to Sheldon Brown's method of bike-locking like I do (Google "sheldon brown lock strategy"). There's not much room left for prying. The included cable is just enough to get through your front wheel and frame and around whatever you're locking to. I usually can't quite manage getting around a fat telephone pole with the provided length, so another foot would be nice, but I've had no problem getting around lampposts and bike racks. If you'd like to get the U-lock (vs. just the cable) around whatever you're locking to, you should probably consider a model with a longer (and maybe wider U) shackle. You might manage to get this smaller lock around a bike rack bar and your rear wheel, but that's pretty tight.
can't be picked with a pen tube: I know from experience that the older Kryptonite locks and some other brands with round keys have this problem. OnGuard locks have a very different key design, and while I generally believe any lock can be picked, I expect OnGuard's locks to be fully pen-resistant.
keyhole cover: Another nice plus is the simple but sturdy keyhole cover that's easy to slide into place, even with gloves on.
key with light: One of the included keys has a little, amber LED in it, which is nice if you've locked your bike in a really dark location and have trouble finding the keyhole, but you really ought to avoid locking your bike anywhere that dark anyway!
scratch-safe surfaces: The only time I have to be careful about scratching my paint job is when the lock is open. The steel ends of the U shackle are (of course) uncoated, but otherwise, the shackle has a heavy rubber coating, and the crossbar has a plastic exterior that seems pretty sturdy and has held up well to over a year of usage. Nice, solid construction.
cons:
possible danger of bending/breaking key: You have to learn to be a little gentle with the lock mechanism. If you have the key all the way in, turning the key should be effortless. If you try to force it, the key feels like it could bend or snap (although I haven't done this yet). Luckily, the lock comes with several keys, in case you need to learn this lesson the hard way. Similarly, when locking, both ends of the U shackle have to be fully seated in the crossbar, or the key will not turn. Bottom line is to remember that unlocking and locking are smooth and easy if the key and shackle ends are all fully in place.
wimpy bracket tab: Although the Amazon product info doesn't suggest that this comes with a quick-release mounting bracket for frame attachment, the one I bought last year did. The plastic tab on the U shackle that slides into the mounting bracket snapped while I was riding, sending the lock into the street. I had the mount on my seat tube, and I think bumps caused the lock to bounce, stressing the tab in the bracket. The OnGuard site advertises a newer bracket whose lock attachment point might be sturdier, but if you insist on frame mounting, you might consider "hanging" the lock on the attachment point by putting the bracket on your top tube. Overall, I recommend carrying the lock in a bag, on a rack, or in a large pocket. (You could also stick it in the back of your pants, which I see some hip fixie riders doing around here, but I can't imagine that's very comfortable.) This was a minor concern to me, since I cycle-commute and almost always have a pannier.
Overall, I'm happy with this lock for medium security (i.e., not NYC) applications, and if used properly, you can generally ensure your bike looks a lot harder to steal than the others on your neighborhood rack. Consider adding a shorter, lighter cable to thread through your saddle rails, if you've got a pricey saddle.
Finally, check out some more information about this lock in an article on Slate. Google for "slate bulldog lock".
The plastic mounting bracket broke on installation... 
2008-07-12
The lock itself seems like it is good quality. However, I never had a chance to use the lock since, the plastic lock bracket, which mounts the lock to the bike broke on installation. As a result, I cannot take the lock with me when I go biking.
The bracket installation guide does not effectively show how to mount the bracket properly to the bike. Even after carefully following the installation instructions, the bracket kept sliding & eventually one of the plastic pieces broke.
Unfortunately, I purchased the lock in May 2008 on Amazaon and I didn't get around to installing the lock until July 2008, which is beyond the 30 day return policy, so I cannot return the lock.
good lock short cable 2008-06-23
The lock works great! Easy to lock and unlock, but the cable that comes with is a little short. I ride to work, and the rack they have is not fully visible to the public. So I was hoping this would be the one sollution for locking my bike. I managed to get the cable all around the bike and use the U-lock at the back tire to connect it all, but I have no extra to connect to the rack. Maybe if I had gotten a bigger U-lock I could connect there? Any ways we purchased a cheap cable lock to connect to the rack also.
Good lock for the price 2008-06-12
I bought this as a second lock. My first lock was a cable. I wanted a good U-lock and settled on this one. Well built, seems to be strong, good mounting system. The addition of a second cable (which I didn't need) was a plus. With this lock and my other lock I feel better about locking up my expensive bike. I gave it 4 stars because the cable could be a little longer, maybe 6' instead of 4'. But its long enough to secure both wheels.
Nice lock, but it's not the one in the picture 2007-10-02
The image shown with this product is actually OnGuard's "Pitbull Mini," which is a step up from the "Bulldog Mini" on offer here. The true "Bulldog Mini," which is what you'll get if you order this product, is black and yellow rather than black and chrome -- look for it in the "other products you might like" sections of this page.
great 2007-09-26
great lock...the best part is that the lock is small enough that you don't even need to use the brace; you can just lock it around the bike frame and it wont hit your bike wheel
