Milenco Dundrod ++ review

Surpassing Sold Secure Gold, the Dundrod ++ has been awarded a Diamond rating as one of the toughest locks out there

Cycling Weekly Verdict

The Milenco Dundrod++ is one of the highest security U-locks on the market. Its heft makes it better suited for security in a single location rather than as an out-and-about lock – but it’s not so heavy that this wouldn’t be an option. Overall an easy to use and reasonably priced Sold Secure Diamond rated lock.

Reasons to buy
  • +

    Very secure

  • +

    Good size

  • +

    Three keys supplied

  • +

    Lock barrel dustcover

Reasons to avoid
  • -

    Not designed with portability in mind

You can trust Cycling Weekly. Our team of experts put in hard miles testing cycling tech and will always share honest, unbiased advice to help you choose. Find out more about how we test.

Based in Milton Keynes, Milenco produces a wide range of security products, including some of the highest security bike locks currently available, such as the Dundrod ++ U-lock.

>>>Read more: Best bike locks

This lock far exceeds the requirements for Sold Secure Gold, being awarded instead the new top-security Diamond rating. As a consequence, the Dundrod ++ is rather hefty — weighing in at around 2.5kg — which makes it best suited for securing the bike in one particular location, although use when out and about is still perfectly possible.


Unfortunately, perfectly secure bike locks simply don’t exist. With the right tools, knowhow and inclination, a thief will be able to get through any lock.

That said, a good lock can greatly reduce the chances of your bike being stolen by preventing opportunistic theft and convincing more systematic thieves that there are easier targets to go for. Perhaps most importantly, a good lock is needed to comply with the wording of your bike insurance policy so that if your bike is stolen, you will at least be covered.

Sold Secure is an independent lock testing company which vets the resilience of locks on the UK market and thereby provides the yardstick by which “goodness” is measured.

Until recently, there three different rankings were awarded, Bronze, Silver and Gold, with Gold usually being required by insurers for bikes worth over £1,000. But now a new “Diamond” rating has been introduced giving recognition to those locks which go above and beyond what’s required for a Gold rating.

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

Increasing protection

If the worth of your bike is measured only by money, then there is little reason to go for a lock stronger than Sold Secure Gold – as this is generally the upper limit of what an insurer will require in order for you to be covered.

But if your bike has a sentimental value or is a model that can’t be replaced, an insurance payout is not going to cover what was lost. In this case, prevention is much, much better than any 'cure'.

Although Diamond rated locks can still be broken — Sold Secure perform this feat themselves during the course of their testing — the amount of time and effort it does take to get through the locks means that thieves are likely to be deterred – and if they are not, the chances of them getting caught are much greater.

Milenco Dundrod ++

(Image credit: Webstockreview)

If securing your bike is genuinely important to you, there are more considerations than just which  particular lock to buy. It’s well worth using two Diamond rated locks as this genuinely does make it twice as hard to steal. Best practice is to lock each wheel to the frame and an immovable object, making sure to go around the rim rather than simply through the spokes.

The object you're locking to does need to be genuinely immovable, being at least equally as secure as the locks. This may mean also purchasing a ground anchor. Also, don’t overlook the security of the place you are locking your bikes, you may need to upgrade the locks to your garage, for example.

To be clear, this level of security would be overkill in most people’s circumstances, insurers wouldn’t generally require you to lock your bike in this way. This is aimed at those whose bikes are genuinely irreplaceable and want to take every step to secure it as well as possible.

The construction

As befits a Diamond rated lock, the Milenco Dundrod ++ is visibly beefier than your usual U-locks. While Silver rated locks tend to have shackles about 11mm in diameter and typical Gold rated locks are around 14mm, the Dundrod++ measures in at a whopping 18mm. The crossbar has been sized up too, making for a reassuringly plump looking lock all-round.

Both the shackle and the crossbar get a comprehensive polymer coating, meaning there’s no exposed metal that stands to potentially scratch your bike. Adding to the Milenco Dundrod ++'s weather resistance is a integrated dustcover for the lock barrel which should help to keep the mechanism from seizing in damp conditions.

Milenco Dundrod ++

Ordinarily, I would be disappointed to see that the shackle is a simple straight design, rather than incorporating a bend in one of the prongs. This means that the two holes of the crossbar have to be lined up with both the prongs of the shackle when locking up. Whereas, a “bent-foot” design would allow you to mount the crossbar one prong at a time – which may not sound so significant, but it really does make locking up a lot easier.

However, a bent shackle does tend to make for a weaker lock. It’s perfectly possible to meet the requirements for Sold Secure Gold rating with one, but for maximum security, it is a design feature that is necessary to leave out. So, in this case this is more of an observation than a criticism.

It’s possible to order more keys, but three come supplied – which is very good to see. When given two, you only have to lose one before the worry starts to set in and you feel obliged to order another. With three, you can lose one and not concern yourself with taking any action immediately as you still one plus a spare (plus if you give it a couple of days the lost one will probably turn up again).

In use

With internal dimensions of 115mm x 225mm, the size is a pretty standard one for a U-lock, making it easy to secure the bike through the frame and wheel against Sheffield Stands and the other usual places you would lock your bike up to.

At around 2.5kg, the Milenco Dundrod ++ is quite heavy for use about town and you do definitely notice its weight on the hills. But it’s by no means an anchor that will cause you to grind to a halt once the gradient tips above 5%.

For context, it weighs about the same as two 1L water bottles with their bottle cages and bolts — and that’s not an especially horrifying prospect to cycle with.

Milenco Dundrod ++

But with that said, use around town isn’t really the purpose the Dundrod++ was designed for – and as a consequence, there is no bike mount supplied to help facilitate that application.

In all, the Milenco Dundrod ++ is quite a straightforward item, it doesn’t perform any party-tricks other than being incredibly secure meaning the experience when using it is quite modestly understated – but that is exactly what you would want from this style of lock.


The value of this style of high security lock is quite tricky to pin down. Diamond rated locks can vary quite widely in price and Sold Secure doesn’t provide any more of a granular stratification comparing which Diamond rated locks are better than others.

You could use price as a proxy for inferring the relative strength of these Diamond rated locks, but it’s worth remembering that the most expensive lock isn’t necessarily the most secure.

With that in mind, Halford’s own Diamond rated Advanced 23cm D lock is £50.00 and comes with a bike mount plus five keys with the option to order more.

On the other end of the scale, the Diamond rated Abus Granit Extreme 59 is £199.99 and also comes with a bike mount but only two keys – although you can order more.

At £89.99, the Milenco Dundrod ++ strikes a reasonable balance between those two price extremes, although it is less portable without a bike mount. However, we haven’t yet tested the other two locks and so can’t vouch for their performance.

Thank you for reading 20 articles this month* Join now for unlimited access

Enjoy your first month for just £1 / $1 / €1

*Read 5 free articles per month without a subscription

Join now for unlimited access

Try first month for just £1 / $1 / €1

Stefan Abram
Tech features editor

After winning the 2019 National Single-Speed Cross-Country Mountain Biking Championships and claiming the plushie unicorn (true story), Stefan swapped the flat-bars for drop-bars and has never looked back. 

Since then, he’s earnt his 2ⁿᵈ cat racing licence in his first season racing as a third, completed the South Downs Double in under 20 hours and Everested in under 12.

But his favourite rides are multiday bikepacking trips, with all the huge amount of cycling tech and long days spent exploring new roads and trails - as well as histories and cultures. Most recently, he’s spent two weeks riding from Budapest into the mountains of Slovakia

Height: 177cm

Weight: 67–69kg