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

Last Updated on September 22, 2022 27 Comments

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!

OnGuard 8020 Mastiff

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.

Product Brand: OnGuard

Editor's Rating:

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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About the author 

Carl Ellis

I've had bikes stolen in London, New York and Barcelona. Yep, I was a serial, international, bike theft victim. In 2015 I decided to stop the rot. And not a single bike's been stolen since! Brakes, yes. Bells, yes. But they're another story. Everything I learn, I document on this website. More about my story. Contact me. LinkedIn.

        • Sorry, My mistake (or Googles, I used the lock info from the BB video and google brought me here).

        • The 8120 is actually the same lock, it’s just a THINNER 8mm chain that couldnt be cut with 40″ cutters. Your claim of worst lock ever is only due to the bronze rating? This lock has hardened pins too that resists hacksaw attacks whereas the Krypto Evo 4 are not hardened. Anyways, after the reviews by Locklabs and LockPickingLawyer I’d say this is actually the best value chain lock on the market.

          • r fumano i wholeheartedly agree with you. and i don’t know what the author is looking at but his alternatives are DOUBLE the price, not the same price! and A LOT of reputable reviewers are having trouble breaking this lock in one way or another. it’s arguably the best bang for your buck. i think someone from the onguard board of directors boinked the author’s wife, got her pregnant and she promptly filed for divorce from said author to be with the board director. nothing else explains this totally unwarranted and factually incorrect review.

          • Can you post links to the reputable reviewers that are having trouble breaking the lock?

            Why do you think it received a Bronze rating from Sold Secure?

            I’m always happy to admit I’m wrong, once I’m proved wrong 🙂

          • as far as the bronze rating, hey at least it placed. most bike locks don’t even place. that in and of itself is impressive. and it’s the only lock i can think of that has THREE positive real world reviews. hal ruzal had trouble with it, lockpickinglawyer had to go to extra lengths (for him), and spend extra time (for him) to pick the lock. i can’t imagine someone on the streets having his knowledge and being able to do that. that alone is a selling point. and look what happened with smash lab bike locks broken. 3 real world reviews. no lock is gonna be invincible but i can’t think of another lock, especially in this price range, with those 3 credentials. that’s good enough for me. mine should arrive tomorrow august 27, 2020.

          • Mmmm I would simply say again, that there’s nothing at all impressive about a Bronze rated bike lock that weighs over 6 lb.

            It relation to the reviews:

            1. The lockpickinglawyer only tested it for picking as far as I remember?
            2. I think the Hal Ruzal test was a video for is that right? I like Hal but the whole video was well dodgy. For example why was the Fahgettaboudit u-lock attacked in a vice but the chains attacked on a bike?
            3. I think the Smash Labs review was just a write up of Hal Ruzal video. I could be wrong though, I can’t remember it that well.

            The bike locks that are recommended by seem to me to be chosen at random. I don’t trust their recommendations at all.

            I agree the price is good. OnGuard prices are always really good. And some of their locks are fantastic.

            If it works for you, that’s great. It’s such a beefy chain that most thieves aren’t even going to try to mess with it.

            And to be fair I haven’t heard of anyone that’s had their bike stolen while using it.

            But my main point stands: if a 10 mm chain is only getting a Bronze rating, there’s something wrong with it.

          • mine arrived today! (8/26/20), a day earlier than expected. excited to use it. although i’ll still be using it wisely of course. i returned a stigtuna u lock that had good ratings in favor of this. i returned that stigtuna because lockpickinglawyer reviewed it and said it’s really 14mm not 16mm. i don’t know if you ever heard of stigtuna and/or what your thoughts may be on that u lock. but i mean, bronze, hey, it got something. it placed. that’s all i could say. admittedly you know way more about this than ME. it’s my first foray into bike locks after a young pretty spanish woman gave me a 21 speed pacific mountain bike that she just didn’t want anymore. it was sitting in the backyard in the rain sleet and snow for like a year. to my surprise everything on it still worked! the brakes, all the gears, everything. front tire just needed air and the back tire had a legit flat. after that it was totally good, no rust or nothing so i decided to salvage it and figured a solid/good bike lock would be a good investment. i don’t know if you feel the 14mm stigtuna u lock would be better than the onguard mastiff chain which actually has a solid 80 on the onguard scale now that i’m looking at the label. i’m also looking and considering the onguard 8001 16mm u lock to either go with this or buy in favor of this. don’t know what your thoughts and considerations would be on that. should i swap out anyone of those for the other? how about the 14mm stigtuna? i’m just deferring to you on this since you know more than me.

          • Well, it’s not just about how well the lock protects your bike.

            It’s also about how easy it is to carry the lock around and how easy it is to use.

            The drawback of a chain is that it’s much heavier than a u-lock. The advantage of a chain is that it generally allows you to lock your bike in places that you can’t with a u-lock.

            So you need to ask yourself: where will I habitually be locking my bike?

            If you’ll usually be locking it to city bike racks, then I’d argue that a u-lock is a better choice as it will fit those racks, be easier to use on those racks and will be much lighter than a chain.

            The Sigtuna is not a good lock. The security to weight ratio will be poor. And it’s likely to start jamming after a short while. I would avoid.

            The OnGuard Brute 8001 is a great lock. Very secure. You still need to clean and lubricate OnGuard locks regularly. But if you do they’ll generally serve you well!

          • ok given your disdain for the onguard 8020 this is what i was gonna do: keep the 8020 mastiff and buy the 8001 brute u-lock to pair with it which would give me a front wheel and back wheel lock OR return the 8020 mastiff and get a schlage 12mm chain with a abus disc lock which would give me just a great back wheel lock OR just stay with the mastiff 8020 considering i’m NOT gonna be leaving the bike outside anywhere much anyway. any of those 3 options preferable??? or should i just swap out the 8020 mastiff for the 8001 u-lock brute? the abus/schlage combo would cost me the same as the mastiff/brute combo. and weight isn’t an issue. the question is, will the mastiff 8020 be enough of a lock for a bike that’s gonna have an affinity for being inside. or will the abus/schlage combo be overkill for a bike that’s gonna have an affinity for being inside.

          • It’s really hard to give specific advise without knowing your specific circumstances.

            You say “weight is not an issue”. Why? You’re talking about carrying around 11 lb of locks. That’s a lot!

            It’s also a lot of bulk. Where on your bike are you going to carry these locks?

            If you’re saying that the bike will be stored inside your house when you’re at home, then you only need a lock for when your out and about.

            In which case I would say you only need the 8001 to protect your frame (and one wheel) if you use a bike stand.

            Then you just need to think about the other wheel. You could use a cable lasso with the Brute. Or you could use Hexlox. Or another lightweight lock.

            It depends on how desirable that other wheel is.

            This should keep your bike safe and be much easier to use than a heavy chain and a u-lock.

            I mean, it doesn’t like it’s a really fancy bike if you’ve kept out in the elements for a year?

          • gonna address your questions in reverse order:

            yea, it’s not a flashy bike or anything but it’s wholly serviceable. incredibly, no major visible rust at all. COMPLETELY functional. gears change, both brakes work. i’d give it’s condition a 7/10. it’s a red pacific oddessy 21 speed mountain bike. worst part about it is the seat. the cushion is torn. nothing else needs replacing. considering the price of bikes nowadays, it’s incredible she gave it to me for free! it’s easily worth at least $150 if not $200.

            yes the bike will be stored indoors at home (private house). and inside the house, not a shed.

            i laughed when you asked where am i going to store all these locks lol. well if i get 2 locks, 1 would be on the bike and i’d keep the other in my backpack. i’m an athlete so i’m accustomed to lifting way heavier weight. i actually thought the 10mm mastiff would be heavier. it’s moderately lighter than i anticipated.

            a majority of the time i’d be taking it to work and keeping/chaining/u-locking it in the break room. i even took it to work one time without the sigtuna and kept it in each room i went to and nothing happened as i kinda suspected. access to these rooms is EXTREMELY limited. and because they’re virtually zero traffic rooms you can pretty easily tell who has gone in there because employees have to sign for the key to enter these break rooms. it seems i’m in the low risk category. i don’t know, perhaps you can assess it better. i’m definitely not in the high risk category. so the question is, which lock would be best for that rare situation when i run to a store or to order take out?? i’m thinking that the schlage/abus combo would be overkill perhaps. i still suspect that the mastiff 8020, although i know you despise it hahahaha, would be more than plenty for those particular low risk instances. but again i’m deferring to you. my concern with the 8001 brute is i suspect that 3mm of those 16.8mm on the shackle is not steel but plastic. i’d need proof that it’s 16.8mm of pure steel. i was deceived like this with the sigtuna u-lock. it’s really a 14mm instead of 16mm shackle. kryptonite locks cost more than i wanna spend. if it’s gonna be a u-lock, then i’m looking for a 16mm. i’m having trouble ruling out the schlage/abus combo. the reason why i’m having trouble pulling the trigger on it is because i seem to be low risk as the bike will only be used in emergency situations and more often than not will be kept in an extremely limited access room to people who can be tracked and with absolutely zero access to the public. so what’s the “prescribed” lock or locks for this situation? curiously, i see bikers with u-locks and chains that appear to be inferior and they’re telling me they haven’t had any issues with those locks so that leaves me feeling i’m superior with the 8020 mastiff. but again, i’m totally deferring to your knowledge on all this.

          • The Brute is far more secure than the Mastiff. I would go with that as long as it allows you to lock your bike where you want to lock it.

  • I have the 72″ version that I keep at work to lock my bike up. Definitely too heavy to carry around. I’ve seen the Bicycling Magazine review and video. I’d really like to know how they defeat this lock in under a minute since Bicycling used a grinder on it for 3 minutes without cutting through, and damaged a large pair of bolt cutters on the chain. Plasma cutter maybe?

    • No I think the weakness is in the mechanism. A hammer attack, a twist or even a pull might defeat it. The OnGuard Mastiff 8019 is the same chain but with a proper padlock and it gets a Sold Secure Gold rating.

  • Hi, very interesting and glad I found this site. I am looking for something to secure my PWC to a dock – so the weight is not an issue as I will not be carrying the chain with me but I definitely want something that would slow down the average thief. Would you still suggest I choose one of the OnGuard 8019 or the Kryptonite Evolution or the Abus or none of the above??


    • Hi Paul,

      Yes the OnGuard 8019 is a pretty secure chain. As are the Kryptonite Evolutions. They can both be cropped though.

      A step up would be the Kryptonite New York chains. They can be cropped too but with much more difficulty.

      I’d imagine the Abus chains are a bit more expensive where you are.

      I’m not too knowledgeable about how you’d lock a PWC to a dock so it’s difficult to give very specific advice. But obviously the further you can keep the chains from the ground the better.

      I hope that helps!


  • i don’t understand how a small u-lock, as on the mastiff 8019, isn’t just as vulnerable as the larger ones in terms of ease of cutting…..

    • It is just as vulnerable in terms of cutting. But much less vulnerable in terms of a leverage attack since it’s more difficult to get something inside the D shape to force it open.

  • Your review omits the word “portable” in the headline but then includes it in the first sentence under ‘introduction’. If “portable” bike locks is what your review is about then i guess the Mastiff 8020 is a “bad” lock. But if you’re looking for “the” best bike lock regardless of portability then perhaps OnGuard Mastiff 8020 is the one. Of course, such a heavy lock has limitations and is best served by LEAVING the lock where you normally park your bike daily: either at work – the Mastiff 8020 stored locked around a metal pole or bike rack in a garage at work, or at home in the garage or elsewhere to further secure your bike against theft if you’re away (many expensive bikes are stolen from inside homes and back yards during burglaries). The 8020 should be seen as a “stationary” lock – not a portable lock. And if you ride to a different location where the Mastiff is not stored then bring with you a lighter lock; I carry a kryptonite series 2 mini U-lock in a small backpack while riding for the past several years. But I’m now researching for a new lock after seeing a cut kryptonite U-lock on the ground next to my locked bike. I’m glad the thief didn’t choose to cut my lock! Sure, something like the kryptonite IS far more portable than the heavy 8020, but someone had their bike stolen…

    Take a look at’s “Smash Lab: Bike Locks Broken”. The 8020 was the only lock they couldn’t break apart using bolt cutters, hacksaw, nor even using a battery-operated angle grinder – which was able to cut thru the heavy Kryptonite Fahgettaboudit in about a minute.

    • Hi Steve,

      Did you read the full review?

      The 8020 isn’t a bad lock because it’s not portable. It’s a bad lock because it’s not very secure. Sold Secure Bronze. And only 78/100 fron OnGuard themselves.

      The “Smash Lab: Bike Locks Broken” was a travesty in my opinion. They seem to have taken the video down now. But as far as I remember, they went at the 8020 while attached to a bike but then put the Fahgettaboudit in a vice.

      You’re not seriously suggesting that the 8020 is more secure than the Fahgettaboudit are you?


    • Actually, he mentions “portable” in the second sentence. A period (.) denotes the end of a sentence. 🙂

  • You biased your review on bronze rating and that’s it. All the other factor (lock picking trials, attack trials) are showing that this is great lock taking into account price vs security level factor. The weight, yes it’s heavy as most chains are. There is no surprise here too.
    So, all in all, putting this chain as the candidate to be worst is made me laugh.

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