Pitlock Pit-Stopper Hex Bolt Security Review

Pitlock Pit-Stoppers

My score:

Check price:


4 mm (M5)
5 mm (M6)
6 mm (M8)
8 mm (M10)


Pitlock is a German company that has quietly been knocking out the world’s most secure bicycle wheel and seat locks for 25 years!

That’s right: while you can always find ways to defeat the other brand’s component locks (if you look hard enough), I’ve never heard of a Pitlock’s skewers and bolts being defeated, by anyone, under any circumstances!

However, they don’t do a huge amount of self promotion, and as a result I was completely unaware that they also produce hex socket locks, which prevent a thief with a hex (Allen) key, going around your bike, unscrewing and robbing any component that’s secured with a hex bolt.

Unboxing the Pitlock Pit-Stoppers

Unboxing the Pitlock Pit-Stoppers

Don’t know what I’m talking about? Don’t worry, I’ll explain everything you need to know, below. Because I got my hands on a set of Pitlock Pit-Stoppers, and I’ve been testing them out on my bike for the last month!

How do Pitlock Pit-Stoppers work?

The average bike is covered in components that are attached with hex bolts. These are the hexagonal shaped screws that you tighten or loosen with a hex (Allen) key. They’re really handy because they’re universal...

Bike components attached with hex bolts

You'll find components attached with hex bolts all over your bike

So if you want to remove a component, all you need is a standard set of hex keys. But that means anyone else, with a standard set of hex keys, can unscrew your hex bolts too, and help themselves to your stuff!

In the “olden days”, some cyclists would try to thwart this type of theft with a DIY method that involved slavering ball bearings in super glue and sticking then in the hex sockets! This works really well by simply making the Hex bolt inaccessible to a key.

Ball bearing in seat clamp

Ball bearing in seat clamp

But unfortunately, if you need to make any adjustments to your components, you first have to go through the messy, time consuming and ultimately very annoying process of dissolving the glue with acetone or Z-7 Debonder!

Pit-Stoppers (just like Hexlox) work by adding a bit of finesse to this old DIY tactic! They essentially do the same thing: they block the hex socket. But they do it in a way that’s easier to install and crucially, much easier to remove if you want to make adjustments.

So how exactly do they work?

With each Pit-Stopper, you get one bolt and two “stoppers”. So each Pit-Stopper can in fact protect two hex sockets.

A Pitlock Pit-Stopper set

Each set contains 2 stoppers to protect 2 hex sockets

To install them, you simply insert a stopper into the hex socket of the component you’re trying to secure, making sure the slightly narrower end goes in first.

Note: it won’t just slide in. It’s designed to be a super tight fit. So the first few millimetres will go in. Then you’ll need to gently tap it in further with a hammer.

The idea is that ultimately, the stopper lies flush with the top of the hex socket. However, I found this will depend on the specific socket. For me, some of them ended up flush. Others simply wouldn’t go in that far.

What’s important is that they’re properly lodged in, so a thief won’t be able to dislodge them and gain access to the hex socket.

How to install a Pit-Stopper

Securing my headset with a Pit-Stopper: tap it into the hex socket with a hammer

You could also apply a little bit of White Lithium Grease to the outside of the stopper to prevent any corrosion fusing the stopper to the socket over time. This will better help it in, and shouldn’t compromise the security of the lock.

But the way you get the stopper out seems so efficient to me, that even in the case of a whole load of corrosion, I don’t think you would struggle to remove them…

So, if you do need to regain access to your hex socket (to make adjustments to your components or replace them etc), then you'll need to use the bolt that comes with the Pit-Stopper set. Simply screw the bolt into the stopper…

The bolt will pass through the stopper and once the tip comes up against the bottom of the hex socket, further turns of the bolt will force the stopper up the shaft of the bolt and out of the hex socket.

How to remove a Pit-Stopper

Removing the stopper: screwing the bolt down, forces the stopper up

Ingenious! As I say, the threaded connection between the stopper and the bolt is so strong and efficient, I can’t imagine a situation where you’d be unable to remove even the most firmly lodged in stopper.

Of course, if you’re out and about and you need to access your hex sockets, then you’ll need to be carrying the bolt. Which is tiny and easily lost! Luckily, Pitlock also sell a small cannister that you can carry on a keyring. This will hold 3 or 4 bolts and a load of the stoppers.

And you might need to carry a few, because the components on a bike are often attached with several different sized hex bolts...

Pit-Stopper sizes

Pitlock Pit-Stoppers are available in 4 different sizes: 4, 5, 6 and 8 mm

So Pit-Stoppers are available in 4 different sizes: 4 mm (M5), 5 mm (M6), 6 mm (M8) and 8 mm (M10), which means you should be able to protect the vast majority (or all) of your components.

How secure are the Pit-Stoppers?

Your first doubt might be: why can’t a thief get a regular bolt (of the appropriate size) and simply screw it into the stopper in the same way as we use the Pitlock bolt? Well, the Pitlock bolt has an irregular thread.

So a normal bolt won’t find any purchase in the stopper. It will just spin around on the surface without passing through.

But what about a brute force attack?

As I’ve already mentioned, I was able to get the stoppers further into some hex sockets than others. And you might imagine that in the sockets where I couldn’t get them completely flush with the top of the socket, I’d be able to somehow dislodge them (with needle nose pliers or the like).

Seat post protected with a Pit-Stopper

A Pit-Stopper protecting my seat: not completely flush, but completely secure!

However, in reality that just wasn’t possible. They never protruded sufficiently to get any kind of grip on them. And even if I could have, they always seemed to be so firmly lodged in, it’s unlikely I’d have been able to remove them.

I’m not saying they’re undefeatable. I’m sure that there are ways to defeat them with specialised tools. But the chances of a thief having those tools and knowing the technique, are so small that they’re insignificant.

It’s true: a thief could buy their own set of Pit-Stoppers and use their bolt to remove your stoppers (because the threads are not unique to your set). But again the chances of this happening are very slim indeed.

My bike locked up in the street

I leave my bike in the street overnight, every night

I leave my bike locked up in the same place, in the same street, overnight, every night. And I know from experience that if the components are not protected, then they’ll be stolen within days (especially the seat and wheels).

I installed the Pit-Stoppers over three weeks ago and I have had no problems at all in an extremely high crime area. So that is good enough for me!

Pitlock Pit-Stopper Summary

I think the Pit-Stoppers are great and I 100% trust them to protect my components. It's true, they might not be as elegant as the Hexlox (which is the other system that protects your components by blocking hex sockets)...

For example, unlike the Hexlox (which uses one key for all the stoppers), you’ll need different “keys” for different sized hex sockets. So you might need up to 4 keys (bolts). And the Hexlox key is much smaller and less intrusive on your keyring than a Pitlock canister.

Hammering a stopper into a hex socket may seem a little more “low tech” than the clever magnetic pull of a Hexlox. And of course, you’ll need a screwdriver as well as the bolt to get the stopper out of the hex socket with the Pit-Stoppers.

Pit-Stopper vs Hexlox

Pit-Stoppers are much cheaper than Hexlox!

However, the Pit-Stoppers are much, much cheaper than Hexlox. It will depend on how many components you need to protect. But if you just need to secure your seat with two stoppers, the Pitlock system will be less than a third of the price of the Hexlox system!

Neither are you dependent on magnetic hex sockets with the Pit-Stopper system. Components that are attached to you bike with Stainless Steel, Aluminium and Titanium hex bolts won't work with the basic Hexlox system. Hexlox make magnetic inserts to convert them but that's an extra cost and they're a bit of a faff to install.

Also, after some time using Hexlox, a build up of corrosion caused one of their stoppers to get stuck in one of my sockets. It wasn’t a big deal. A good soak with WD-40 and a bit of wiggling soon released it.

But with the Pit-Stoppers, the connection between bolt and the stopper is so tight, that I don’t think that would ever happen.

Various Pit-Stoppers together

Pit-stoppers: clever, lightweight and hassle free bicycle component security!

In terms of security, while both of them can be defeated if a thief has the right tools and the know how, in reality this is very unlikely to occur, and I’ve never heard of either system being defeated in the street.

So I see the Pit-Stoppers as the economical option. While not quite as easy to use as their rival, they’re still a very clever, lightweight and hassle free way to protect your bike components for a very reasonable price.

 And I highly recommend them!

Pitlock Pit-Stopper Specs

Pitlock Pit-Stoppers

My score:

Check price:


4 mm (M5)
5 mm (M6)
6 mm (M8)
8 mm (M10)