Zéfal K-Traz U17 review

Surprisingly lightweight, this is one of the most affordable Sold Secure Gold locks available

Cycling Weekly Verdict

The Zéfal K-Traz U17 is really great value for money. It makes a Sold Secure Gold rated lock a lot of accessible and it tips the scales at a surprisingly low 1.28kg. The plasticky bike mount is a bit of a lowlight but at this price – and considering the otherwise great performance – this is easy to overlook.

Reasons to buy
  • +

    Great value

  • +

    Sold Secure Gold rating

  • +

    Significantly lighter than expected

Reasons to avoid
  • -

    Plasticky bike mount

  • -

    Straight shackle

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The Zéfal K-Traz U17 is a low cost Sold Secure Gold rated D-lock. It’s very lightweight for its size and price, and comes shipped with a bike mount — making it good for use around town as well as being a high security option at home.

>>>Read more: Best bike locks

Having recently celebrated its 140th birthday, Zéfal is a French company with a long heritage in the bike industry. Although facing stiff competition from manufacturers in the Far East, Zéfal’s affordable product lines mean that it continues to scoop up a fair chunk of the market share.


It’s an unfortunate truth that no bike lock is perfectly secure. A determined thief – with the right tools, knowhow and inclination – will always be able to break through. Instead, a good quality bike lock serves to prevent opportunistic theft and to convince more systematic thieves that there are easier targets to go for. But the most important function is to comply with the wording of your bike insurance policy – so that you are at least covered if your bike is stolen.

Sold Secure is an independent lock testing company which tests the resilience of locks on the UK market. Three levels of ranking are awarded. The lowest, Bronze, means the lock is only suitable for preventing opportunistic theft. Silver is generally regarded as good for moderate crime areas and for bikes valued up to £1,000. While Gold should be used in high crime areas and for bikes valued over £1,000. It should be specified in the wording of your insurance policy what level of lock you need to use to be covered.

>>>Read more: How to keep your bike safe

The construction

Protecting the paintwork of your frame from any scrapes is a smooth plastic coating that surrounds all the exposed surfaces of the Zéfal K-Traz U17. The design actually looks really quite classy and belies the low price of this lock.

The shackle is a pretty standard size for a U-lock at 11.5cm x 23cm giving a lockable area of 265cm2. However, the prongs of the shackle are both straight, meaning they have to be lined up together with the crossbar to lock the lock. Other U-locks have a bend in one of the prongs so that the crossbar can be fitted one prong at a time – which really does make a palpable difference to the ease of use.

Zéfal K-Traz U17

The lock barrel on the crossbar features an integrated weather seal, which should help to extend the lock’s longevity, particularly if often used outside. Popping the lock on the scales, it came in at 1.28kg which is significantly less than the claimed weight of 1.47kg. I assume Zéfal must have weighed literally everything the lock comes with. And indeed, when I put the mount, spare bolts for the mount, all three keys and keyring, manual and cardboard packaging onto the scale, it did shoot up to 1.44kg – although this was still lighter than the claimed weight.

I find weighing the lock on its own is the fairest measure, as some locks (such as the Kryptonite Messenger Mini With U-lock Extender) don’t come with a bike mount; 1.28kg is really quite light for a Sold Secure Gold rated lock of this size and the fact that the K-Traz U17 is significantly cheaper than much of the competition, this weight is doubly impressive.

In use

Setting up the bike mount was quite straightforward, only needing two bolts to be screwed in to attach it to the frame. A longer pair of bolts was also provided for use on tubes up to 80mm in diameter, but these weren’t necessary for me.

Attaching the lock to the mount is something of a different story. The plastic bracket itself feels quite tacky and I found the release button for extracting the lock once it’s mounted to be quite difficult to press sufficiently for getting the lock out.

Zéfal K-Traz U17

Aside from that, however, the lock was excellent to use. In being a fairly standard size, it was quite easy to lock the bike in a range of locations using a variety of different immovable objects — the larger lampposts were off limits as ever they are with a normal sized U-lock. The plastic coating did the intended job of protecting my frame from any scuffs and scrapes.

Three keys were provided with the lock and it’s possible to order more should you need to. Beyond that, there isn’t much more to add regarding its performance in application. It did the job simply and effectively, which is exactly its purpose – even if that doesn’t lend itself to flowery descriptions.


Comparing the Zéfal K-Traz U17 to the Kryptonite Messenger Mini With U-lock Extender, the Kryptonite costs £74.99, weighs 1.11kg, is Sold Secure Silver rated, and has a lockable area of 236cm2. Whereas the Zéfal is less than half the price, 170g heavier, Sold Secure Gold rated and has a slightly larger lockable area – although it doesn’t pack down as small.

The Oxford Alarm-D Pro is Sold Secure Gold rated, has a motion sensitive alarm, an intuitive bike mount and a “bent foot” shackle – which makes mounting the crossbar easier – but retails for £60.99. If you have the money to spare, the Oxford lock is packed with features and is very well executed. But if cost is the bottom line, then the Zéfal K-Traz U17 would be the better choice.

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