Mason 180 - SEATYLOCK


Mason 180

World's Lightest Sold Secure Diamond U-Lock!

Unique triangular crossbar profile for best strength/weight ratio. Double deadbolt locking mechanism for protection against twist attacks. *Mounting Bracket sold separately

Hear what our customer has to say about his Mason Lock

    Customer Reviews

    Based on 13 reviews
    Great lock

    Can’t beat the size and weight. This is the best U lock I’ve come across and I feel very secure leaving my bike wherever I go during the day.
    The 180 is perfect for my road bike and I’d purchase again in a heartbeat.

    Great lock

    Sturdy, very light weight. Perfect size for my hybrid bike in a large city.

    Jeremy T.
    Better than expected.

    I bought the Mason 180 as the main lock for my Trek Dual Sport bike, and on arrival was blown away by the quality of this thing. The key turns smoothly, the lock opens and shuts nicely and it isn’t near as heavy as other locks of the type. I’ve seen complaints about the zip ties that come with the mount for this but I found they worked really well (even after my dog chewed halfway through one, leaving it held on by only 1.5.

    Definitely recommend the mount too, but mounting was my only disappointment with this thing. I have a decently large frame bike and there is nowhere on my inner frame I can mount this while also having a water bottle mounted. I found most of the rest of the recommended mounting angles awkward or in the way of body motion while biking, fortunately my bike has a back rack mounted on it and I was able to mount the lock to that instead.

    Overall, great lock at a great price. Just check the measurements against your fame before buying for mounting reference!

    next level

    Mason 140/180 locks are a relative joy to use. The 140 has been just enough in all situations so far with my steel-framed road bike. Rigid & grippy, no wobble on Seatylock mount, and a significant bit lighter to make these next level products to own. I do wish that it had been made more clear that (3) keys are included, as I had purchased as many spares again with the lock order and at a very high cost. Gotta make some time to follow up on that ~ No time for photos of this type either, but you get the picture -

    Perfect U-Lock

    Very nice lock, You can feel the quality. Just the right size, fits back wheel through the triangle to a post every time.

    William Richards
    Damn good security

    Somebody can always bust your lock, but they’ll break a sweat to get to your bike

    Eric Lewis

    Great size for getting the frame and wheel without much extra room

    Jessica Machado
    Great lightweight lock

    I'm really impressed with the design and light weight of this lock.

    Anthony Corrado
    highest security at bargain price

    Seatylock Mason U-locks have all earned the highest Sold Secure Diamond rating along with only a few of the top models from bigger brands that are much heavier and way more expensive. Mason model numbers refer to the inside length in mm. The Mason 140 & 180 are 85 mm wide inside while the 220 & 300 are 115 mm wide.
    I chose the 180 because it fit within my frame along with a bottle cage and tire pump with enough room to easily mount and remove it from the bracket attached to the seat tube.
    Considered a compact U-lock, the Mason 180 is just big enough to attach one wheel and part of the frame to a post with no room for a thief to get in with large wrecking tools. Otherwise it will fit around most posts and just one tube, but you should also carry a good foldable lock, chain or cable (at least 10 mm thick) if suitable posts are not available and also to secure removable parts like wheels and the saddle.
    The shackle is hardened steel with a triangular profile for the 140 & 180 and pentagonal for the 220 & 300 and is thick enough to stop a bolt cutter and really slow down an angle grinder. The locking bar is steel, reinforced where the shackle is secured at both ends by a spring-loaded mechanism that prevents it from rattling and falling out when unlocked. The pick-resistant lock cylinder has a spring-loaded dust cover. The optional bracket can be mounted in various locations on the bicycle, attached by 2 plastic hose clamps. It has a push-button lock and is snug enough to resist vibration.
    Shipping is free in the U.S. The shipping cost to me in Canada was mostly offset by the fact that no sales or import taxes were charged. You can contact the Seatylock site for prices and availability. Even if it may take a few weeks to get the Mason size you want, it will be well worth the wait.

    Alexander LIvshitz
    Great lock!

    I haven't used it yet (still haven't bought a new bycicle), but it looks and feels very strong and solid.
    The delivery was super fast: less than 3 days to another continent - the fastest delivery I ever had!
    And the price is really fair, too.
    Great job, guys, definitely recommended!

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