The Litelok Silver Flexi U lock is easy to use, secure, and surprisingly light compared to more traditional U locks.
The two key elements that set the Silver Flexi U apart from traditional U (or D) locks are its flexibility and weight. One issue with traditional D locks is that they're unmovable and rigid because of the materials used, normally hardened steel. If you were able to bend and mould steel easily then you would also be able to break it. But this also means you're limited on where you can use them.
For the Flexi U, Litelok has used its Boaflexicore technology. Rather than being made of one piece of steel, it uses 200 strands of steel within a rubberised outer. If one strand is broken, the lock isn't compromised, plus it means the lock is very flexible compared to traditional D locks.
It's also much lighter. The large size I tested hit the road.cc Scales of Truth at just 750g. For comparison, the Abus Granit X-Plus D lock that Dave tested was 1,525g (although it has a Sold Secure Gold rating, while this is Sold Secure Silver), and the OnGuard Brute U lock is even heavier at 2kg, although it is around £30 cheaper. The Litelok comes in a smaller size too, which weighs a claimed 640g and costs £69.99.
With its lightweight design and flexibility, the Flexi U is easy to carry around with you. It comes with Velcro straps so you can attach it to your frame, although for the majority of my review I just chucked it in a rucksack.
The weight saving is great for travelling, but the element that I found most useful was being able to lock my bike up in more places. For instance, this lock can fit around lampposts, which most traditional D locks can't – the 10 million or so lampposts in the UK now become bike racks. Yes, you could lock your bike to them before with other locks, but those would either lack the security of a D lock or be too unwieldy to be practical.
Using the Litelok is a bit different to most D locks in that you do not have two component parts. Instead, it is one continuous band, so you don't get that irritation of the other side of the lock falling off and having to be repositioned before you can make it secure. With the Flexi U, one end of the band has a cylinder that slides into the corresponding slot on the opposite side, then you just turn the key and it's locked.
Comparing the price of the Litelok with others is a little tricky because it's so different; if you were to compare it to other Silver rated locks it seems expensive – you can buy Sold Secure Gold locks for less – but no other D lock has this level of flexibility and light weight.
Overall, I was really impressed by the Flexi U. It is highly innovative, light, and flexible enough to solve one of the major issues with most other D locks. Perhaps it could be cheaper given its Silver rating, but to be honest I think that its practical elements more than justify the additional spend.
Innovative lock that offers the security of a D lock with the light weight and flexibility of a cable
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road.cc test report
Make and model: Litelok Silver Flexi U lock
Size tested: Large
Tell us what the product is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
Litelok says, "Cyclists can now buy a lock in the same convenient format they know and love but with the Litelok Flexi-U they will have loads more places to which they can lock their bike... and it's 50% lighter.
Litelok Flexi-U Silver's flexibility ensures riders have more options when securing their bike. Unlike stiff rigid locks, it is able to bend around street furniture such as sign posts, lamp posts, telegraph poles and trees.
"ENGINEERED FOR SECURITY
The Litelok Flexi-U has been security tested using common bike theft tools, simulating real-life street theft attacks as well as being tested under lab conditions, using machines that can apply forces far greater than any human can.
"DESIGNED FOR YOU
Litelok Flexi-U Silver has turned a very tired, and traditionally heavy, product category on its head. Not only is it flexible, it also has the same vertical locking system as Litelok Silver, giving you a downward line of sight making it easier to open and close your lock."
This is exactly what I found: the ability to lock it in more places and the reduced weight make it a real game changer.
Tell us some more about the technical aspects of the product?
Diameter: 27cm x 11.5cm
Seems very well made.
Performed very well, enabling me to lock my bike securely to objects that traditional D locks would not have been able to.
Not much to go wrong apart from the lock mechanism, which seems robust.
It is around half the weight of traditional D locks.
Tricky one: it's not cheap compared with other Sold Secure Silver D locks, but those don't offer the same the combination of qualities.
Tell us how the product performed overall when used for its designed purpose
Very well: it's light, flexible, and simple to use.
Tell us what you particularly liked about the product
Although the weight is a real bonus, the flexibility is undoubtedly the element that really sets this lock apart.
Tell us what you particularly disliked about the product
The flexible nature of the design for a D lock is a genuine game changer. It meant that if a bike rack was full up, I could easily just lock my bike to a nearby lamppost without any issues.
Did you enjoy using the product? Yes
Would you consider buying the product? Yes
Would you recommend the product to a friend? Yes
Use this box to explain your overall score
A Sold Secure Silver rating combined with a weight of 750g and the flexibility to use it in such a variety of places leads me to conclude that the Flexi U is exceptional.
About the tester
I usually ride: CAAD13 My best bike is: Cannondale Supersix Evo
I've been riding for: Under 5 years I ride: Every day I would class myself as: Expert
I regularly do the following types of riding: commuting, club rides, sportives, general fitness riding, fixed/singlespeed, mtb,
George spends his days helping companies deal with their cycling commuting challenges with his company Cycling for Work. He has been writing for Road.cc since 2014.
When he is not writing about cycling, he is either out on his bike cursing not living in the countryside or boring anybody who will listen about the latest pro peloton/cycling tech/cycling infrastructure projects.