OnGuard 8020 Mastiff: Is this the worst bike lock ever?

OnGuard Mastiff 8020

OnGuard 8020 Mastiff Summary

My score:

Check price:

Chain thickness:

10 mm


6.28 lb (2.85 kg)


43.0" (110 cm)

OnGuard rating:


Other Security Ratings:

Sold Secure Bronze

The OnGuard 8020 Mastiff is a strange beast. A thick chain lock, with 10 mm, titanium reinforced hardened steel links, it should be one of the best portable bike chain locks available today.

But it’s not.

In fact, it’s a contender for the worst bike lock ever. Read on to find out why. In this review I look at how easy it is to carry around, how easy it is to use and how secure it is. Finally, I suggest some better alternatives!

Is the OnGuard 8020 Mastiff easy to carry around?

With links that are 10 mm thick and a total length of 43.0″ (110 cm), the 8020 can still be classified as a “portable chain lock”. By that, I mean a chain that you could carry about with you every day to lock your bike in the street.

Once the links get to around 12 mm, chains become so heavy and unwieldy that they’re impractical to carry around and are best used as stationary security at home or work.

But obviously the length of the chain is important too, this is just a rough guide. You can read more about portable vs stationary chains on my best chain lock page. And more about the best way to carry bike locks on my where to put a lock when your riding page.

Carrying a chain lock around is pretty straightforward. There’s no frame mount to worry about. You can just wrap it round your seat post and you’re good to go. Or, some people like to sling it over their shoulders like a bandoleer. Easy. The problem with chain locks though, is the weight…

The 8020 weighs 6.28 lb (2.85 kg). That’s the equivalent of 7.5 cans of coke. So while it’s perfectly possible to carry this chain around every day, it is very heavy. And you’re really going to notice that weight whether you sling it over your shoulders or wrap it round your frame!

Is the OnGuard 8020 Mastiff easy to use?

Measuring 43.0″ (110 cm), the 8020 should give you plenty of options when you’re looking for places to lock your bike in the street. And at home it’s probably long enough to secure two bikes.

If you do need something longer, the 8021 Mastiff [Amazon] is essentially the same lock but with a 72.0” (183 cm) chain. Of course it’s much heavier too, coming in at 9.84 lb (4.46 kg). That’s 11 cans of coke!

The actual lock is integrated into one end of the chain. This makes it quicker and easier to get the chain around your bike and locked up than if you had to fiddle around with a separate padlock.

The 8020 comes with five keys, including one with a light to help you out in the dark. Like all OnGuard locks, if you register your keys online, should you ever loose them, OnGuard will send you replacements for a small fee.

Be aware though, registering directly through OnGuard is for US customers only!

How secure is the OnGuard 8020 Mastiff?

No surprises so far. We know a big chain like this is going to be heavy, but fairly straightforward to use. And we’d also expect it to also provide a pretty high level of protection. Unfortunately it doesn’t.

The chain itself is made from 10 mm thick, titanium reinforced, hardened, square steel links. It’s a very good chain. In fact, when the famous Hal Ruzal tested this lock for Bicycling magazine, the battery on his portable angle grinder died before he could cut through it!

However, if we look at the security ratings for the 8020, they are extremely worrying. OnGuard themselves give it a very mediocre 78/100. And Sold Secure only rate it as Bronze.

That’s the lowest rating that Sold Secure award! The Bronze rating is reserved for locks that give very limited protection.

This must be something to do with either the locking mechanism itself or the join where the chain meets the lock on the 8020 (and the 8021). Because the other Mastiff chain locks are rated much higher.

For example, the 8019 Mastiff [Amazon] which is essentially the same chain but with a separate, miniature u-lock, gets an in-house rating of 92/100 and a Gold award from Sold Secure. (And it costs more or less the same price by the way!)

So in fact, this lock is not very secure at all. Sure, locking your bike with a hefty 10 mm chain is going to give you a psychological advantage over an opportunist thief. And many will be deterred by it’s size alone.

But I don’t want to pay this much money and carry this much weight around, in return for psychological protection alone!

Because anyone who knows what they’re doing will defeat this lock in seconds. To be rated Bronze by Sold Secure, a lock only needs to withstand a one minute attack with basic tools.

That’s it. That’s the criteria for the award. So this lock could be defeated in 61 seconds with basic tools!

And that’s why I don’t recommend any locks that are rated Sold Secure Bronze. The very minimum protection you should be looking for is Sold Secure Silver.

Just to drive this point home, the 8020 Mastiff offers you the same practical level of protection as the 7 mm Kryptonite Keeper or the 6 mm Hiplok Lite.

And even though they are less than half the price and a fraction of the weight, I wouldn’t recommend these locks either!

Does the OnGuard 8020 Mastiff include insurance?

Like most OnGuard locks, the 8020 Mastiff is eligible for coverage from their in-house Anti-Theft Protection programme.

Under this scheme, if your bike is stolen as a result of this lock being defeated, OnGuard will pay you up to $2001 towards a replacement, depending on the value of your bike. Again, this is for US customers only.

I’ve written about these schemes in great detail on the Abus vs Kryptonite vs OnGuard page. But to summarize here: you need to register for this programme as soon as you buy the lock, it’s not free and the chances of OnGuard ever paying out are very, very slim.

Much better to get your bike covered under your house insurance or take out specialist bicycle insurance instead.

OnGuard 8020 Mastiff Review Summary

I’m not dogmatic when it comes to recommending bike locks! I won’t say that the Kryptonite Fahgettaboudit Mini is indisputably the best bike lock because it’s the most secure u-lock. Or that you should never buy a budget lock because they offer limited protection.

All bike locks offer a compromise between price, practicality and security. And the best bike lock for you will depend on what value you give to these qualities within the limits of your individual circumstances.

The best bike lock for you won’t be the best bike lock for someone else.

And in fact, the aim of this website is to help you find a lock that will both adequately protect your bike and suit your circumstances so that it’s easy and painless to use every day. But I just can’t see this lock being the best lock for anyone’s circumstances.

But I’m not beyond making generalizations! I think we can all agree that ideally, the best bike lock would be light and cheap and strong? So does that mean that the worst bike lock would be heavy and expensive and weak?

Because if it does, then the OnGuard 8020 Mastiff is a definite contender!

In fact, I can’t think of a bike lock that offers a worse balance of price, practicality and security. So until otherwise, I award the OnGuard 8020 Mastiff the dubious honour of the worst bike lock ever!

But what do you think? Can you think of a worse bike lock? Let me know below…

Alternatives to the OnGuard 8020 Mastiff

Luckily there are plenty of alternatives to the 8020 chain lock…

Looking for something more secure?

OnGuard 8019 Mastiff

The OnGuard 8019 Mastiff [Amazon] uses the same great chain as the 8020 but replaces the rubbish integrated lock with a separate, high security, miniature u-lock that has a 14 mm shackle.

This completely changes the security rating of the lock, giving it 92/100 from OnGuard themselves and a Gold award from Sold Secure.

It’s also more or less the same price as the 8020. In fact I’ve often seen it cheaper! The only disadvantage is that using a chain with a separate lock can be a little more fiddly. So…

Something that’s more secure with an integrated lock?

Kryptonite Evolution Series 4 1090

The Kryptonite Evolution Series 4 1090 [Amazon] is another 10 mm chain with an integrated lock. This one is rated Sold Secure Gold though.

At 36″ (90 cm), it’s slightly shorter than the 8020 Mastiff. But this means it’s also slightly lighter at 6.10 lb (2.77 kg). And once again, it’s often cheaper than the 8020 too!

If you’re looking for something longer, then the next size up is the Series 4 1016 [Amazon]. It’s 63″ (160 cm) but is also significantly heavier at 9.70 lb (4.40 kg).

Or even something that’s more secure and lighter?

Abus CityChain 1010 110

It’s not often you can recommend an alternative lock that is both significantly lighter and more secure!

But while the Abus CityChain 1010/110 [Amazon] is the same length as the 8020, it weighs over 10% less and is rated Sold Secure Gold.

Now, although Abus steel is renowned for it’s strength to weight ratio, I’m dubious as to whether it would fare better than the 8020 against a pair of 42″ bolt cutters!

But overall it would appear to be stronger and in fact this is one of my favourite portable chain locks.

Don’t like any of these locks? Check out the ultimate guide to choosing the best bike lock. Just follow the 3 simple steps!

OnGuard 8020 Mastiff Specs

OnGuard Mastiff 8020

OnGuard 8020 Mastiff Summary

My score:

Check price:

Chain thickness:

10 mm


6.28 lb (2.85 kg)


43.0" (110 cm)

OnGuard rating:


Other Security Ratings:

Sold Secure Bronze

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Last Updated on June 29, 2021 by Carl Ellis

Carl Ellis
Review Details
Review Date
Reviewed Item
OnGuard 8020 Mastiff Bike Chain Lock
Author Rating
Product Name
OnGuard 8020 Mastiff Bike Chain Lock
USD 65
Product Availability
Available in Stock
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