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OnGuard Bulldog DT Review

The Bulldog DT is large and accommodating, but if you need a U-lock for higher security needs, this one might not be the best option
onguard bulldog dt bike lock review
Credit: OnGuard
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Price:  $45 List | $43.80 at Amazon
Pros:  Inexpensive U-lock, durable, good quality
Cons:  Lacks the security of better U-locks, clunky design, mount is not our favorite
Manufacturer:   OnGuard
By Rebecca Eckland ⋅ Review Editor  ⋅  Jan 26, 2022
Our Editors independently research, test, and rate the best products. We only make money if you purchase a product through our links, and we never accept free products from manufacturers. Learn more
55
OVERALL
SCORE


RANKED
#17 of 18
  • Security - 40% 6.0
  • Ease of Transport - 25% 4.0
  • Ease of Use - 20% 6.0
  • Versatility - 15% 6.0

Our Verdict

The OnGuard Bulldog DT is a decent U-lock for a lower price than most options from reputable lock companies. The U-Lock is a bit larger than most, making it more likely to accommodate your bike's front wheel (removed from the front fork), back wheel, the bike frame, and the bike rack. It also comes with a mount so that you can attach the lock to your bike frame, but we didn't like it very much. The robust mount and the lock's design make it a solid medium-security U-lock. According to its manufacturer, it has a double-locked shackle design, requiring bike thieves to make two cuts on the U-lock and not just one, which adds to its security. Interestingly, we could defeat it with one cut through the shackle with an angle grinder. It lacks the protection that other U-Locks in our best bike lock review provide, and depending on your biking equipment and wheels, we think you should pass on this if you need higher security.

Editor's Note: We updated this gear review on January 25, 2022, to include additional information on whether this product is worthy of purchasing and other options to consider.

Compare to Similar Products

 
onguard bulldog dt bike lock review
This Product
OnGuard Bulldog DT
Awards  Best Buy Award Best Buy Award Top Pick Award  
Price $45 List
$43.80 at Amazon
$80 List
$50.40 at Amazon
$51.07 at Amazon
Compare at 3 sellers
$18.00 List
$18.00 at REI
$12.99 at Amazon
Compare at 2 sellers
Overall Score Sort Icon
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55
46
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Pros Inexpensive U-lock, durable, good qualitySecure, includes 5 keys, price is niceInexpensive, more secure than many in its price range, high qualityLightweight, easy-to-carry, easy-to-useLightweight, flexible, easy to use
Cons Lacks the security of better U-locks, clunky design, mount is not our favoriteClunky mounting hardware, heavyLocking mechanism stuck a few times, lackluster frame mountMinimal security, can be compromised with the right tools quicklyToo small, minimal security
Bottom Line The Bulldog DT is large and accommodating, but if you need a U-lock for higher security needs, this one might not be the best optionThis lock provides great security and versatility at an affordable price, and while not our absolute favorite, it's pretty closeThis inexpensive U-lock offers versatility and security that is likely to fit the needs and budgets of many cyclists and commutersIf you're in the market for a highly portable and lightweight lock but without much security, this one has your name on itGreat for preventing the "snatch and grab" while you make a pit stop but does little to prevent a real bike thief from swiping your ride
Rating Categories OnGuard Bulldog DT OnGuard Brute STD Kryptonite Kryptolo... ABUS Chain Lock 120... Hiplok Z Lok
Security (40%)
6.0
9.0
6.0
3.0
1
Ease of Transport (25%)
4.0
3.0
5.0
9.0
10.0
Ease of Use (20%)
6.0
6.0
7.0
7.0
7.0
Versatility (15%)
6.0
7.0
7.0
4.0
2.0
Specs OnGuard Bulldog DT OnGuard Brute STD Kryptonite Kryptolo... ABUS Chain Lock 120... Hiplok Z Lok
Measured weight (lbs) 3.0 lbs 3.6 lbs 3.2 lbs 0.5 lbs 0.1 lbs
Type of lock U-Lock + cable U-Lock U-Lock + cable Chain Reusable zip tie
Primary materials/thickness 13mm steel; braided steel cable 16.8mm hardened steel 12.7mm hardened steel; braided steel cable 4mm hardened steel Steel core security tie
Locking dimension U-lock: 6" x 11"; Cable: 4' 7.5" x 10.5" U-lock: 4" x 9"; Cable: 4' 43" circumference 16.5" circumference
# of keys included 5 keys 5 keys 2 keys N/A 1 key
Tin snips No No No Yes, requires two cuts to defeat Yes
Hammer No No No No Yes
Hacksaw Yes, eventually No No No Yes, quick
Bolt cutters, 36" No No No Yes, but not very easily. Requires two cuts Yes
Angle grinder Yes Yes Yes Yes Yes
Number of cuts to free lock 1 cut 2 cuts 2 cuts 2 cuts 1 cut

Our Analysis and Test Results

Performance Comparison


onguard bulldog dt bike lock review - the bulldog u-lock and cable combo is a basic, but decent, bike lock.
The Bulldog U-lock and cable combo is a basic, but decent, bike lock.
Credit: Rebecca A. Eckland

Security


We didn't find much to get excited about in terms of security. Granted, it's a less expensive U-lock, but OnGuard gives the Bulldog DT a "70" or "high security" rating according to its internal rating system. We could agree if they are referring only to the U part of the lock. However, our testers discovered that the shackle is this lock's vulnerable spot.

onguard bulldog dt bike lock review - the 13mm thick u of hardened steel was easier and faster to cut...
The 13mm thick U of hardened steel was easier and faster to cut through with the angle grinder than higher-end U-locks.
Credit: Rebecca A. Eckland

The Bulldog is burly for thieves with hand tools: there's no getting through this lock with hammers, tin snips, wire cutters, or bolt cutters. Once you introduce power tools into the equation, it's over, as with all locks. What downgrades the score of this lock is how quickly we were able to cut through this lock compared to other thicker U-locks we tested. This bike lock quickly succumbed to an electric-powered angle grinder within mere seconds. The worse news? If thieves can cut through the shackle, which we accomplished much easier than expected, that disables the metal plate that locks the U into the shackle. So, in one cut, thieves can nab your bike and gear. Therefore, we generally recommend U-locks that require two cuts to the U portion, or at least a shackle that's more difficult to cut through.

onguard bulldog dt bike lock review - the shackle was the weak point for this lock...and once the shackle...
The shackle was the weak point for this lock...and once the shackle is compromised, your bike is as good as gone.
Credit: Rebecca A. Eckland

Ease of Transport


If you're not necessarily "handy," installing a bike mount could be something of an adventure. Perhaps having this in mind, the designers at OnGuard created a bike mount that is simultaneously robust and easy to install, even if you're not all that skilled at that sort of thing. The low-profile mount fits on most frames and keeps the lock in place, even on some rough roads. The mount is sturdy. However, many of our testers didn't love that it positions the 3-pound lock off-center on the bike. We prefer lock mounts that keep the lock streamlined with the bike frame. If you're toting the included cable around for additional security, it will need to be carried in a pack.

onguard bulldog dt bike lock review - the mount that comes with the onguard bulldog is reliable on paved...
The mount that comes with the OnGuard BullDog is reliable on paved roads, but if your ride is particularly rough, you might want to look for other frame mounting options. We also wish it didn't stick off-center from our frame.
Credit: Rebecca A. Eckland

While the OnGuard Bulldog DT isn't the heaviest U-Lock in our lineup, we bet you'll notice the extra three pounds of weight on climbs no matter if the lock is mounted to your frame or is stuffed into your backpack. That's just part of being a U-lock, and actually, this one is lighter than several models. It's also a larger lock, so if you ride a smaller frame (read: 50cm or smaller), you might not be able to mount this lock directly to your frame. Larger sizes mean they can fit around more objects but also more of a bear to transport.

onguard bulldog dt bike lock review - the on-guard bulldog dt lock offers medium security and a surprising...
The On-Guard BullDog DT lock offers medium security and a surprising bit of versatility for a low-cost U-lock. Here, the lock is shown with an after-market mount that holds the lock more securely.
Credit: Rebecca A. Eckland

Ease of Use


Our testers complimented the OnGuard Bulldog for how easy it was to use. There was no fighting or odd "grippiness" to this lock. Every time we used it, it came apart and locked up smoothly.

onguard bulldog dt bike lock review - with five keys, a nice size-u and an easy-to-use lock, there was a...
With five keys, a nice size-U and an easy-to-use lock, there was a lot to like about the OnGuard Bulldog.
Credit: Rebecca A. Eckland

We also appreciated that this lock comes with five keys — one of which has a light on it. If you're a busy bike commuter, it stands to reason that you might misplace a key. Having four extras is excellent insurance that you won't run out of them too quickly.

What is not easy to use is OnGuard's protection policy which claims that it will reimburse you up to $1501 if your bike is stolen using their lock. What they put in the fine print is that you have to register your lock and pay to register it in order to qualify. And, if you happen to have your bike stolen and you want to collect on this policy, you must provide them with receipts for the lock, the bike, an evaluation of the value of the bike, and then proof that the lock failed (most often: the broken lock itself). As you can imagine, this isn't an easy thing to do. Because of this, we didn't add any extra points to this metric because we assume most riders will not be able to collect on this policy. Most theft insurance policies follow this scheme (OnGuard is not the only company to flash big dollar signs and then have rigid stipulations). For this reason, we don't put much weight behind these theft protection policies.

onguard bulldog dt bike lock review - the on-guard bulldog dt lock offers ample versatility for a low-cost...
The On-Guard BullDog DT lock offers ample versatility for a low-cost U-lock. We were able to lock both our wheels to most bike racks with the Bulldog. The cable is useful to secure our bike saddle, when necessary.
Credit: Rebecca A. Eckland

Versatility


Our testers were impressed with this U-Lock that enabled us to secure our commute bikes to nearly any bike rack and use the most secure method: locking the front and back tires next to the frame with the bike rack. There were only a handful of situations where we encountered a bike rack or on the trailhead where due to the constraints of simply being a U-Lock, we couldn't lock our bike securely. But, in conventional urban settings, this lock is adeptly versatile.

onguard bulldog dt bike lock review - the bulldog dt lock offers average security and a surprising bit of...
The Bulldog DT lock offers average security and a surprising bit of versatility for a low-cost U-lock.
Credit: Rebecca A. Eckland

The U-Lock includes a 4-foot cable, which could make this lock a bit more versatile if you live and commute in a low-risk area. However, we recommend locking both tires to the frame and bike rack. If you seek a lock for medium-risk areas, the cable isn't going to do much than deter a snatch-and-grab opportunist. Note: you cannot use the cable on its own, and once the U-lock is defeated, the cable is also defeated.

onguard bulldog dt bike lock review - the longer-than-most onguard bulldog dt adds versatility...
The longer-than-most OnGuard Bulldog DT adds versatility, accommodating more objects inside the u-lock.
Credit: Rebecca A. Eckland

Should You Buy the OnGuard Bulldog DT?


The OnGuard Bulldog DT is ok, but its clunky design, off-center mount, and lower security (as far as U-locks are concerned) didn't entirely impress us. Since there are better options, we recommend that our biking friends spend a bit more money to get a better bike lock.

What Other Bike Locks Should You Consider?


There are plenty of other bike locks in the review that don't cost a whole lot more, but that will offer you more security and peace of mind, such as the OnGuard Brute STD. This option is wallet-friendly and offers more security.

onguard bulldog dt bike lock review - while the onguard bulldog comes with a 4' cable, we wouldn't...
While the OnGuard BullDog comes with a 4' cable, we wouldn't recommend using it to secure expensive components unless you are in a low-risk area.
Credit: Rebecca A. Eckland

Rebecca Eckland
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