Onguard 8003 Pitbull STD U-Lock review: Affordable, high security lock best suited for e- and cargo bikes

Whether you’re riding electric or analogue, carting cargo or commuting to work, keeping your bike secure when it’s locked up is a top priority. That’s why we always recommend investing what you can into one of the best bike locks.

Of course, not everyone has bottomless pockets to spend on the snazziest security tech, so fortunately there’s a variety of options on offer that shouldn’t break the bank. When it comes to the best budget bike locks on the market, you may have seen the brand Onguard come up here or there, and we recently spent some hands-on time with its 8003 Pitbull STD U-Lock to check if it’s up to scratch.

If you’re riding an e-bike or cargo bike, a much higher-value target for organised thieves, then you’ll want one of the best e-bike locks, which tend to be Sold Secure Diamond rated. Despite its sub-£50 price tag, the 8003 Pitbull does just that, and promises the ultimate protection against a range of attacks.

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If you’ve taken out one of the best bike insurance policies that requires a lock with a Gold or Diamond rating, and balked at the price tag that comes with many of them, then the 8003 Pitbull might well be worth your consideration. But how well does it actually perform? Read on to find out.

Design and aesthetics

The Onguard 8003 Pitbull is a standard D-lock (or U-lock), with a curved shackle and lock cylinder that attaches in two places. The 14mm hardened steel shackle is protected by a co-moulded rubber coating to prevent scratches or damage to your bike’s frame. With a locking area of 115 x 230mm, it’s very large, which makes it versatile for different locking setups, whether you're securing a bike frame and wheel together, or tackling more awkwardly-shaped anchor points.

It may be bulky and feel rather unwieldy in hand, but it does come with a bracket so you can mount it to your frame. Compatibility with compact frames is a bit of an issue (more on this below), but anyone riding a medium frame or above can benefit from the highly adjustable OnGuard bracket that’s small enough to be tucked neatly under the top tube. This means it’ll work well with dropped seat stays and provides lots of mounting options, if you have the real estate to accommodate it.

One aspect that might be off-putting for some is the weight. At 1.44kg, it’s very hefty, so it makes more sense to use it with e-bikes or cargo bikes, since the percentage of added weight will seem much lower in the grand scheme of things. I would say that I can’t imagine anyone mounting it to their road bike, but since I had only an aluminium road bike to hand for the testing period, that’s exactly what I did.

In terms of visual deterrence, the 8003 Pitbull features bright yellow accents that stand out and signal to passing opportunists that there’s a bike lock in place, while the very chunky lock cylinder and overall size give an impression of strength that should put some people off trying their luck.

The design does have some shortcomings, though. Instead of a plastic keyhole covering that you tend to find on other D-locks, the Pitbull has a spring-loaded anti-pick mechanism in place, comprising two metal plates that you pry apart with the key. It may well keep the lock from being picked and the internals shielded from the elements, but it’s still exposed metal that might be vulnerable to long term rusting or corrosion. Plus, I genuinely don’t believe there’s that much of a risk that someone will spend time trying to pick the lock, and would much prefer a completely weatherproof solution that prolongs its lifespan instead.

Included with the lock and frame mount are a generous five keys, including a larger one with a built-in light for nighttime use. This is a very nice touch, and paid dividends during my October/November testing period.

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Security

With Sold Secure Diamond certification, the Onguard 8003 Pitbull promises peace of mind for the owners of expensive bikes, including e-bikes and cargo bikes. It’s especially well suited to those who need to meet insurance criteria for high-security locks.

The 8003 Pitbull features an X4P Quattro Bolt locking mechanism that secures the shackle on four sides. This is designed to withstand leverage and twisting attacks. The lock’s 14mm hardened steel shackle is thick enough to resist bolt cutter attacks, while the Z-cylinder, as mentioned above, is designed to protect against picking, as well as pulling and drilling. Onguard rates the 8003 Pitbull as ‘Ultimate Security’ — 80/100 on its own scale — and buyers can register for up to $2,251 (about £1,800) of anti-theft protection.

So it comes with excellent security credentials, while still costing less than £50. However it could have some limitations. While the X4P Quattro Bolt should in theory be enough to resist prying and twisting attacks, I question whether it’s enough to compensate for the extra space inside the lock. The shackle is very large, and unless you’re securing a hefty frame (like an e-bike or cargo bike), there’s a lot of room leftover to move the bike away from the anchor point. With that space, it doesn’t take much to insert a pry bar and apply force. Even with the X4P mechanism securing the shackle on all sides, the leverage created by a bar could still be enough to do the job. Maybe it outperforms single- or double-locking designs, but it can only do so much if the lock itself isn't snugly positioned.

On top of this, it’s worth also noting that although it can stand up well against hand tools, it doesn’t account for portable angle grinders, which are definitely on the rise in urban areas.

Performance

When I unpacked the Onguard 8003 Pitbull, my first thought was, ‘this is massive, is it even going to fit on my frame?’. As someone who rides an XS bike, I’m not part of a majority, but us short folks aren’t in such short supply either. This is often a concern for many of us, and it didn’t go unfounded.

It takes a bit of time and puzzle solving to figure out the best placement on the frame, and the very chunky cylinder lock means that in most cases you’re likely to feel it against your leg. On a larger frame, it might be a little easier to find the optimal placement, but on my XS frame, I was fighting an uphill struggle against losing both my bottle cages, clearing the cranks, and not needing to pedal with one knee pointed outwards.

In the end I lost one of those battles, sacrificing my bottle cages for comfortable pedalling, and while the result ended up being for the most part comfortable to ride with, for me this was only a temporary measure for the testing period, but I wouldn’t recommend it for commuter cyclists riding small frames. Hydration is important!

Plus, the only way I could make it work with my bike resulted in the metal end of the cylinder being pressed right up against the frame, which would no doubt wear down my paintwork (and the tube itself) over time. Larger frames are less likely to be affected by this, but for smaller bikes, the mounting experience was far from ideal.

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On a more positive note, both the frame mount and the lock itself offer a lot of adjustability for tailoring the fit. You secure the frame mount with two screws, which, when loosened, allow you to rotate it and adjust the angle to suit your frame. The round vice section holding the lock also has a central screw for rotating between a vertical or horizontal position. A second bracket attached to one of the shackle’s prongs slots into the frame mount and is secured in place by a spring-loaded mechanism that you release using the yellow button to load and unload it. For even more adjustability, you can loosen the screws on the shackle bracket to rotate it for a more refined fit on the bike.

Once everything is set up, loading and unloading the lock is straightforward, by simply pushing the button to release the grip.

During my testing period, riding with the Onguard 8003 Pitbull was mercifully quiet, however this is mostly down to the fact that it was pressed against my frame. During the setting up process, when I tried out a couple of other potential positions (that were difficult to comfortably pedal with), it rattled like crazy.

The lack of a weatherproof keyhole cover is disappointing as well, especially for a lock marketed as weather-resistant. The anti-pick mechanism worked smoothly during testing, but I’m dubious about its longevity if it’s exposed to rain and dirt over time, particularly for those who store their bikes outside regularly. A regular spray of GT85 on the internals wouldn't go amiss.

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Verdict

The Onguard 8003 Pitbull STD offers Diamond-rated security at an affordable price, making it a good option for anyone needing to satisfy insurance providers on a tight budget. It is very versatile when it comes to different locking options, offering enough space to navigate thicker and less conventionally shaped anchor points, and it offers exceptional value for money.

Its large size and hefty weight make it cumbersome (and potentially incompatible) with compact frames, but it would work very well for e-bike and cargo bike riders. If you have a medium sized frame or larger, need the Sold Secure Diamond rating, and are confident that it will fit snugly enough to resist prying attacks, then this is an excellent choice of lock.

For riders of smaller you may want to consider one of the other locks in Onguard’s Pitbull series, like the 8006.