On-Guard Mastiff Keyed Chain Lock

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Brand ONGUARD
Special Feature Portable
Lock Type U-lock
Item dimensions L x W x H 4.33 x 9.06 x 1.57 inches
Material Hardened Steel shackle

About this item

  • Steel/Vinyl
  • U-Locks

From the manufacturer

ABOUT US

On the inside, OnGuard locks comes with double and quad-locking mechanisms, bump-resistant cylinders, and hardened steel shackles and chains. On the outside, our locks are fully-coated to protect your bicycle or powersport vehicle from scratches and to shield internal parts from the elements, while the bright color scheme sends a clear warning to thieves: don’t even try! And then there’s the extras: all-tube mounting brackets, five laser cut keys, key-code registration, comprehensive anti-theft programs.

Product Description

The superior protection of our X4P locking mechanism mated to a standard length 230mm 9.06'' 14mm 0.55'' TriRadius hardened steel shackle for more locking options.

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Customer reviews

4.4 out of 5 stars
4.4 out of 5
736 global ratings

Customers say

Customers like the quality, sturdiness, and value of the lock. For example, they mention it's well-made, solid, and won't be easy to crack. Some appreciate the quantity, and ease of use. That said, opinions are mixed on size, portability, and mounting.

AI-generated from the text of customer reviews

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QualitySturdinessValueQuantityEase of useSizePortabilityMounting
82 customers mention "Quality"59 positive23 negative

Customers like the quality of the lock. They say it's a solid lock, with tight tolerances and it'll keep thieves from cutting it. The lock is heavy, well made, and durable. It's easy to lock and unlock, and performs flawlessly. Some customers also say it is a great U lock for electric bicycles.

"...Easier to use than those circle-wound cable locks, and quite a bit more secure...." Read more

"...through so for the money spent i think it is great value on a fairly heavy duty lock, I would buy again at this point." Read more

"...The lock held up really well. I do not recommend ever leaving a bike parked overnight in NYC unless the bike is worth $75...." Read more

"This is a decent u-lock, and cheaper than Kryptonite's overpriced options, but the plastic casing is not particularly high quality and even brand new..." Read more

69 customers mention "Sturdiness"51 positive18 negative

Customers like the sturdiness of the lock. They mention that it seems very solid, has a semi-hard, black plastic layer over the metal bar, and the key mechanism is solid and operates smoothly. The lock is sturdy and definitely won't be easy to crack, with a thick shackle and steel is very strong.

"...Comes with a mounting clip that is screw on, not flimsy like the others that have a pull-tight mount...." Read more

"...It seems very thick and should take someone a bit of time to try and hack through so for the money spent i think it is great value on a fairly heavy..." Read more

"...This lock has a solid tumbler & shackle that operate cleanly. And when it gums up I just squirt some WD40 (as suggested by the owners manual)...." Read more

"Bike attachment crews seem prone to stripping so be careful and concise with your tools, just use a screwdriver anyways so you don't crack the..." Read more

31 customers mention "Value"27 positive4 negative

Customers like the value of the lock. They say it works great for the price, is reasonable, and is an excellent lock for the money. Some mention that it works as well as a good bludgeon as o a lock and that it's a small price to pay for security.

"...Great value for the price, I'd recommend this lock to any bike owner." Read more

"...time to try and hack through so for the money spent i think it is great value on a fairly heavy duty lock, I would buy again at this point." Read more

"...This lock has a solid tumbler & shackle that operate cleanly. And when it gums up I just squirt some WD40 (as suggested by the owners manual)...." Read more

"Very hefty, solid lock. It looks quite nice too...." Read more

13 customers mention "Quantity"13 positive0 negative

Customers are satisfied with the quantity of the lock. They mention that it comes with several keys, a large frame for bigger poles, and an unusual key that they've never seen before. The keyhole is recessed and appears well protected from anything but a key.

"...Comes with 5 keys (1 big, 4 small) which is nice but unnecessary for my use...." Read more

"...Moreover, each lock includes 5 spare keys and a tag to allow you order replacements. You can tell these guys know their stuff." Read more

"...It comes with lots of keys which is nice...." Read more

"...Pros: Heavy duty, bike mount, several keys, large frame for bigger poles..." Read more

12 customers mention "Ease of use"12 positive0 negative

Customers find the lock very easy to use. They say the attachment is really easy to set up, carry, and install. Some say the key version is convenient to use and the security level is higher.

"...Attachment is really easy to use, the design of it is smart. Gripes are minor." Read more

"...lock, oh they are laser cut so they are pretty nifty looking and harder to pick...." Read more

"I have peace of mind with this lock. It is easy to use and the mounting bracket allows me to easily take it wherever I go...." Read more

"...seen before that looks like it would be hard to pick but goes in and out very easy...." Read more

31 customers mention "Size"18 positive13 negative

Customers are mixed about the size of the lock. Some mention that it's big but with the clip on it goes easily on the bike, while others say that its needlessly odd shape and overly large size made it difficult and even too big for their M365 scooter.

"Great lock, easy to lock and unlock. It is big and fairly long however it just missed being able to get my front tire and frame (24 inch) together..." Read more

"...of the the design, although rarely, its needlessly odd shape and overly large size made it difficult and even impossible to fit in a few places,..." Read more

"...the u-bar itself wouldn't be, but it does seem to have a superior width and weight. Attachment is really easy to use, the design of it is smart...." Read more

"...The size is perfect for going through the frame and wheel of the bike and around a signpost. Not much wiggle room left after that...." Read more

28 customers mention "Portability"14 positive14 negative

Customers are mixed about the portability of the lock. Some mention it's sturdy but easy to carry, while others say it'd be better if it wasn't so awkwardly weighted.

"Heavy - works as well as a good bludgeon as a lock..." Read more

"...The only real cons I have with it are the awkward and bulky style of the actual lock part of the the design, although rarely, its needlessly odd..." Read more

"...i went with this U lock and it does the trick, feels secure and easy to travel with." Read more

"...the bike frame mount, that will eventually break because the lock itself is heavy and in order to keep the mount from slipping you have to tighten..." Read more

19 customers mention "Mounting"12 positive7 negative

Customers are mixed about the mounting of the lock. Some mention that it's heavy duty, convenient, and perfect. However, others say that the mounting bracket broke after a few months of use, the screws were all busted, and the mounting part on the lock twists.

"...Comes with a mounting clip that is screw on, not flimsy like the others that have a pull-tight mount...." Read more

"After 6 months of daily use, the mount first broke in the front, making the lock very loose and wiggly, and then in the back, making it impossible..." Read more

"...First is the on-bike clip is comes with, most u-locks use a slide into place clip, this one used a sort of side clip that I find vastly superior the..." Read more

"...One amazing reason to get this lock in particular? It comes with a mount for the lock...." Read more

Very Secure Lock.
5 out of 5 stars
Very Secure Lock.
A very good lock. It's kind of big but would be very hard to break. Didn't like bracket that came with lock so I just put around seat post and rear carrier.
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Top reviews from the United States

M. Butler
5.0 out of 5 stars Great Lock
Reviewed in the United States on September 27, 2012
Size: 4.53" x 9.06"Style: ModernVerified Purchase
Ordered this because it looked tougher than the other U-locks that can be had for $10-40. It might take a minute or two with an angle grinder (not verified) but it'll deter thieves with hacksaws and bolt cutters. Comes with a mounting clip that is screw on, not flimsy like the others that have a pull-tight mount. Comes with 5 keys (1 big, 4 small) which is nice but unnecessary for my use. I use this to lock my bike in the back of my truck (with a cable) and on campus. Easier to use than those circle-wound cable locks, and quite a bit more secure. On campus, this fits through the rear of the frame and rear wheel, securing all but the front wheel of my bike. This won't fit around your seat tube and rear wheel, you'll need something bigger for that. Great value for the price, I'd recommend this lock to any bike owner.
5 people found this helpful
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jivor50
5.0 out of 5 stars Good value lock.
Reviewed in the United States on August 25, 2017
Size: 4.53" x 9.06"Style: ModernVerified Purchase
Great lock, easy to lock and unlock. It is big and fairly long however it just missed being able to get my front tire and frame (24 inch) together on same lock so I had to go with the frame when I purchased this for an event. Luckily the event customers were very nice and didn't take my front tire but I didn't expect that to happen either. It does come with a bike mountable holder which is nice and it keeps the lock securely in place when riding. It seems very thick and should take someone a bit of time to try and hack through so for the money spent i think it is great value on a fairly heavy duty lock, I would buy again at this point.
2 people found this helpful
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Tony M.
5.0 out of 5 stars A solid lock with a good key design.
Reviewed in the United States on December 23, 2013
Size: 4.53" x 9.06"Style: ModernVerified Purchase
Locks are simple tools that need to do a few things perfectly. So far this lock has prevented my bike from being stolen, so that's a nod to its credibility. What's important to me is that the shackle opens and shuts reliably. In this case the OnGuard is flawless. I open and close my lock 10 times a day as I'm running errands, arriving at work etc. I've had other locks that were a pain to open & close. This lock has a solid tumbler & shackle that operate cleanly. And when it gums up I just squirt some WD40 (as suggested by the owners manual). Moreover, each lock includes 5 spare keys and a tag to allow you order replacements. You can tell these guys know their stuff.
One person found this helpful
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Peter
5.0 out of 5 stars Screws, locking, and bike attachment
Reviewed in the United States on August 13, 2015
Size: 4.53" x 9.06"Style: ModernVerified Purchase
Bike attachment crews seem prone to stripping so be careful and concise with your tools, just use a screwdriver anyways so you don't crack the plastic.

Not the easiest to re-lock as you have to leave your key in for it to go in all the way and activate the lock, but I suppose I'll get in the habit of doing so soon enough.

Otherwise seems like a solid lock. Was concerned from other reviews stating the lock is heavy that the u-bar itself wouldn't be, but it does seem to have a superior width and weight. Attachment is really easy to use, the design of it is smart. Gripes are minor.
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John R. Baxter
3.0 out of 5 stars Solid Lock with a good holding mechanism.
Reviewed in the United States on February 10, 2014
Size: 4.53" x 9.06"Style: ModernVerified Purchase
The lock functions as you would expect any good U lock to. but there are a couple things that make this one a little unique. First is the on-bike clip is comes with, most u-locks use a slide into place clip, this one used a sort of side clip that I find vastly superior the the other type, this makes it so that you can mount the lock in places where a traditional style clip may not allow you to remove the lock. Another thing I like is the self closing keyhole, many locks have a plastic cover you can turn to cover the keyhole of the lock when not in use, but this model has a little spring loaded door that you push the key through and that closes when you pull the key out, it's nice for keeping moisture and debris out of the lock mechanism. The lock is also well padded, making sure that although rugged and heavy, it isn't going to ding up your bike. The only real cons I have with it are the awkward and bulky style of the actual lock part of the the design, although rarely, its needlessly odd shape and overly large size made it difficult and even impossible to fit in a few places, making the lock pointless, and the other is the BS guarantee that is offered. U-bar locks aren't invincible, and with the right tools (a cordless angle grinder) and a little privacy they can be cut through in less than a minute. Knowing this the makers have written their guarantee to be void if the lock is cut with a power tool, which makes it worthless, so if you were looking at this lock because of its guarantee don't bother.

All in all it's a great lock and I'd recommend it to anyone looking for a U-bar lock.

Pros
+ on-bike clip is superior to other locks
+ self- covering keyhole
+ well padded
+ overall sturdy look and feeling

Cons
- Overly bulky and odd shaped Lock
- 100% BS protection guarantee

Lock would be an easy 4 star if they didn't try to trick me with a guarantee that is worded to be worthless.
29 people found this helpful
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T
4.0 out of 5 stars Great protection, a couple of small design issues
Reviewed in the United States on April 15, 2015
Size: 4.53" x 9.06"Style: ModernVerified Purchase
Very hefty, solid lock. It looks quite nice too. One small problem is that the thick base plate part is so chunky that if I mount it on the saddle, it gets in the way of my thigh when pedalling. I've had to move it down to the main frame of the bike, and there is pretty much only one option in terms of positioning where it won't rub against my legs, so the placement is not very customizable for my bike anyway.
I haven't had any problems with the lock sticking as yet in the few months I've owned it. I sprayed a bit of silicone oil into the lock when I first received it. The size is perfect for going through the frame and wheel of the bike and around a signpost. Not much wiggle room left after that. The smaller version would have been too small, and the longer version should be good for 2 bikes or for locking your bike to a lamppost. I pair this with a kryptonite 7' cable to secure my front wheel and saddle as well. The 4' cable would have been far too short for this.
One other thing that annoys me is the quick release. The part of it which clamps onto the U lock and allows you to attach it to your bike always works loose so when I try to just snap it in place, the attachment just slips and rotates and doesn't lock in place. I have to hold the latch open and slot the attachment into place which is a bit of a hassle and could have been avoided with better design. I'll probably just epoxy the attachment to the U lock at some point to avoid this.
2 people found this helpful
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Top reviews from other countries

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KAISO
5.0 out of 5 stars O cadeado que tanka o Brasil
Reviewed in Brazil on July 31, 2023
Size: 11.5 x 29.2 cmStyle: Keyed Shackle LockVerified Purchase
Pontos positivos: Ele é robusto, realmente resistente, por isso bem pesado, me programo quando vou precisar usá-lo para não ter que levar peso extra. Achei diversos vídeos gringos testando ele, e em todos a galera só conseguia romper com uma serra elétrica, sabemos que isso aqui em terras tupiniquins não é uma tecnologia muito usada por ladrões de bicicleta, então dessa forma não conseguirão rompelo, mas se atente para o material da base onde você prende a bike, se for bicicletário entorta roda, esse aí é facilmente rompido por serras comuns.

Ponto negativo: essa versão não vem com a extensão para prender as rodas, que é um ponto negativo para quem usa blocagem nas rodas, o material pode ser adquirido no site do Jack Chan, mas, pelo menos para onde eu moro, o frete custa o mesmo preço do cabo extensor, então é melhor ir em uma loja de material de construção, pegar dois metros de cabo de aço e prender com braçadeira, que é basicamente isso o que o cabo extensor é.

Sobre a fechadura: Vi algumas reclamações que ela emperra, realmente, no início a chave é mais difícil de entrar do que os cadeados de 20 reais, no entanto isso se deve à robustez do acessório e o fato de ser novo, comprei grafite e tudo foi resolvido, ficou fácil abrir e fechar o cadeado depois disso, não coloquem óleo de máquina ou qualquer outro óleo, cadeado se lubrifica com grafite.

Conclusão: Parece caro, mas sua bike é muito mais, além disso, investir nisso vai te poupar a dor de cabeça de ter seu bem roubado.
11 people found this helpful
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poddio
5.0 out of 5 stars Diamond rated lock for a great price
Reviewed in Canada on March 23, 2022
Size: 4.53" x 9.06"Style: ModernVerified Purchase
I bought two of these locks for our electric bikes after doing a lot of research. They are diamond rated by SoldSecure, meaning they are about as tough as you can get for a bike lock, and they qualify for bike insurance. In the US, the company insures your bike in the event it's stolen with the lock on. It's a heavy lock, but all similarly rated locks are just as heavy. It's also much less expensive than bigger brand names like Kryptonite. Comes with four keys, and one of the keys has an included light for use in the dark. Great deal in my opinion.
One person found this helpful
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Hector Marquez
5.0 out of 5 stars 100% recomendado
Reviewed in Mexico on January 3, 2021
Size: 4.53" x 9.06"Style: ModernVerified Purchase
Las primeras impresiones son de un candado de gran calidad. Es pesado, pero es un sacrificio mínimo para mantener tu bicicleta segura. Terminamos comprando un candado igual para la bicicleta de mi novia. 10/10
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Alejandro D.
5.0 out of 5 stars Seguridad/precio
Reviewed in Spain on November 8, 2022
Size: 4.53" x 9.06"Style: ModernVerified Purchase
El candado es de muy alta seguridad ahora bien, viene justo de engrase y más vale que lo aceites de vez en cuando porque después de unas lluvias puedes verte con una bici que no puedes desencadenar, y este no lo cortas con ninguna cizalla. Repetiré
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Simone natalizi
5.0 out of 5 stars Come da descrizione...Ora vediamo i Fatti🤟
Reviewed in Italy on May 28, 2020
Size: 4.53" x 9.06"Style: ModernVerified Purchase
Corrisponde perfettamente alla descrizione...sembra molto robusto e funzionale anche x una fat ebike cm la mia!Ora speriamo che faccia anche il suo "sporco" lavoro.
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