The 5 Best Alarmed Motorcycle Disc Locks for UK Riders (2026)

Last reviewed: April 2026 (Sold Secure ratings confirmed, prices checked) Alarmed disc locks recommended for UK riders storing motorbikes outside, covering home use and carrying on the bike.

The short version: An alarmed disc lock is the noise layer in a layered security setup. It will not stop a determined thief on its own, but combined with a chain and anchor it means any attack on your motorbike happens with a 100-120dB siren screaming for attention. At that point most thieves move on. This guide covers five options at different price points, all independently tested or with verifiable Sold Secure ratings. Affiliate disclosure: if you buy via our links, we earn a small commission at no extra cost to you.

An alarmed disc lock does two things. It physically prevents the wheel from turning, which stops a ride-away theft. And it triggers a loud siren when the bike is moved or interfered with, which draws attention and forces a thief to work under pressure. Neither of those functions alone is impenetrable, but together, and as part of a wider security setup, they make a genuine difference.

Before going through the products, it is worth being honest about what an alarmed disc lock is not. It is not a substitute for a chain and anchor. A bike secured only with a disc lock can still be lifted into a van with the lock intact. The alarm will go off in the back of the van, which is unhelpful for the thief but does not get your bike back. For outside storage, a disc lock works best as the third layer after immobility and alongside a cover, not as the sole security measure.

With that said, here is what matters when choosing one.

• Reminder cable. Riding off with a disc lock fitted is a surprisingly easy mistake and an expensive one. A brightly coloured reminder cable attached from the lock to the handlebars removes that risk. Many locks include one; for those that do not, it is worth buying separately.
• Pin diameter. The pin passes through a ventilation hole in the brake disc. Larger pins are harder to cut but need larger holes to fit through. Most modern motorcycle discs will accept a 10mm pin; some will accept 14mm. Scooters with smaller discs often need a smaller pin. Check your disc hole size before buying.
• Alarm volume and sensitivity. 100dB to 120dB is the standard range. 120dB is loud enough to be genuinely unpleasant at close range. Sensitivity matters too: too sensitive and it fires in wind or when a lorry passes; too insensitive and it misses a real attempt. Look for motion-sensing rather than vibration-only alarms, as motion sensing is harder to fool.
• Weather resistance. UK weather. A disc lock that sits on a brake disc outside in all conditions needs to work reliably in rain, cold, and damp. Some alarms are significantly quieter when wet. Check for weather-resistant alarm modules.
• Sold Secure rating. As with all security products, an independent Sold Secure rating tells you the lock has been physically tested rather than just described as secure. For disc locks the relevant rating is Sold Secure Motorcycle Gold or above.

* Affiliate links. If you buy via these links, we earn a small commission at no extra cost to you.

1. Abus Granit Detecto XPlus 8077: Best Overall

💰 ~£100–£130 |🏆 Sold Secure Motorcycle Gold |🔊 100dB alarm |📌 13.5mm pin |⚖️ ~560g

Abus is a German security manufacturer with a long track record in high-quality locks, and the Granit Detecto XPlus 8077 is their flagship alarmed disc lock. It holds Sold Secure Motorcycle Gold rating, Thatcham approval, and the kind of build quality that is immediately apparent when you handle it. The 13.5mm hardened steel bolt is at the larger end of what disc locks offer and resists cutting attempts that would defeat smaller pins.

The alarm uses a 3D position sensor rather than a basic vibration sensor, which means it detects movement in any direction rather than just vertical shock. In practice this makes it considerably more sensitive to real theft attempts while being less prone to false alarms from wind or passing vehicles. The 100dB siren is loud and clear rather than the tinny sound some cheaper units produce.

The double-bolted locking mechanism is a meaningful security detail. When the pin is engaged it locks at both the top and bottom of the body, which means even if the pin is partially cut it remains very difficult to remove the lock. A rotating dust cover protects the keyway, and the lock body has a corrosion-resistant coating that holds up well to UK outdoor conditions. A reminder cable and carry pouch are included.

The 13.5mm pin will not fit some older or smaller brake discs. It is worth checking your disc ventilation hole size before ordering, as this is the most common reason for returns on this lock.

Verdict: 

The most comprehensively approved alarmed disc lock on this list. Sold Secure Gold, Thatcham approved, double-bolted, and with a 3D sensor that performs better in real conditions than basic vibration-only alarms. The right choice if you want the most credible lock for insurance purposes and genuine attack resistance.

---

2. Oxford Boss Alarm Disc Lock: Best Mid-Range Pick

💰 ~£55–£75 |🏆 Sold Secure Motorcycle Gold |🔊 100dB alarm |📌 14mm pin |⚖️ ~580g

Oxford is the most recognised name in UK motorcycle security at the accessible end of the market, and the Boss Alarm Disc Lock is their flagship alarmed disc lock. It holds Sold Secure Motorcycle Gold rating, is widely cited as Thatcham approved, and at 14mm has the largest pin diameter of any lock on this list. That 14mm pin is the same diameter as the shackle you would find on a serious padlock, which gives some context to its resistance to cutting attack.

The hardened steel body and pin are paired with a 100dB alarm that triggers on movement or significant shock. A coiled reminder cable is included and is long enough to stretch comfortably from a rear disc to the handlebars, which is the most useful placement. The lock includes four keys rather than the two supplied with many competitors, which is a small but practical touch.

Oxford's widespread availability is a genuine practical advantage. The Boss Alarm is stocked at Halfords, SportsBikeShop, and most motorcycle accessory retailers online and in-store, which means competitive pricing, easy replacement if needed, and straightforward returns if there is an issue. For a rider who wants a Sold Secure Gold alarmed disc lock from a brand with a broad UK service network, this is the most accessible option on the list.

The alarm sensitivity has been noted as slightly lower than the Abus in some comparative tests, meaning it requires a more significant disturbance to trigger. For most outside storage situations this is a minor point, but worth knowing if your priority is maximum alarm sensitivity.

Verdict: 

The most practical mid-range choice for most UK riders. Sold Secure Gold, the largest pin on this list, widely stocked, and competitively priced. If you want a reliable, insurer-recognised alarmed disc lock without spending over £100, this is the natural choice.

---

3. Xena XX15: Best Premium Option

💰 ~£120–£160 |🏆 Sold Secure Motorcycle Gold |🔊 120dB alarm |📌 14mm carbide-reinforced pin |⚖️ ~770g

Xena is a specialist motorcycle security brand and the XX15 is their top-of-range alarmed disc lock. The 120dB alarm is the loudest on this list and genuinely unpleasant at close range. The 14mm pin is carbide-reinforced rather than plain hardened steel, which provides additional resistance to cutting attack. The stainless steel mono-bloc body resists corrosion and direct attack well, and the double-locking mechanism means a cut pin is still very difficult to remove from the disc.

What distinguishes the XX15 beyond its specifications is the ice-spray resistance. Freeze attacks, where a thief sprays a lock with freezing agent to make the steel brittle before striking it, are an increasingly used method on higher-quality locks. Xena have specifically engineered the XX15 to resist this approach. For a high-value motorbike stored outside in an urban area where determined theft is a realistic risk, this is a meaningful feature that most competitors do not address.

The alarm uses both shock and motion sensors, providing the two-layer detection that is harder to defeat than single-sensor designs. At 770g it is on the heavier side for a disc lock, which makes it less practical for regular carrying but well suited to home use on a driveway or in a side passage. A reminder cable is included.

The XX15 is at the premium end of the disc lock market and the price reflects it. For a high-value bike in a higher-risk location, it is a well-justified investment. For a lower-value bike or a lower-risk situation, the cost is harder to justify against the Oxford Boss or Zovii at lower price points.

Verdict: 

The premium choice for a high-value motorbike in a higher-risk location. The loudest alarm, carbide-reinforced pin, ice-spray resistance, and dual sensors make it the most comprehensively specified alarmed disc lock on this list. Weight makes it better suited to home use than regular carrying.

---

4. Zovii ZD10S: Best Value Pick

💰 ~£45 |🏆 Sold Secure Motorcycle Gold |🔊 120dB alarm |📌 9.95mm carbide-reinforced pin |⚖️ ~622g

The Zovii ZD10S is a relatively new entrant to the UK market, sold exclusively through SportsBikeShop, and it has rapidly earned a strong reputation through independent testing. Bennetts BikeSocial reviewed it in January 2025 and found it one of the most effective alarmed disc locks tested at its price point. The stainless steel body, carbide-reinforced pin, hardened rotating top plate to defeat drilling, and 120dB alarm are specifications you would expect to pay considerably more for.

The alarm was tested through a month of outdoor exposure in rain and freezing temperatures and continued to perform correctly throughout, which is a meaningful real-world data point for UK outside storage use. At 9.95mm the pin is narrower than some competitors but the carbide reinforcement means it is harder to cut than plain steel pins of larger diameter.

It is important not to confuse the ZD10S with the cheaper ZD10, which has a zinc alloy body and meaningfully lower attack resistance. The S suffix denotes the stainless steel version, and the difference in construction quality between the two is significant. The ZD10S is the one worth buying.

Three keys are supplied and the alarm arms and disarms with audible beeps that confirm status clearly. For a rider who wants Sold Secure Motorcycle Gold and a 120dB alarm without spending £100 or more, the ZD10S is an outstanding value proposition backed by credible independent testing.

Verdict: 

The best value alarmed disc lock on this list by a clear margin. Sold Secure Gold, 120dB alarm, carbide-reinforced pin, and independently verified outdoor performance for under £50. The only meaningful drawback is single-retailer availability. Buy the ZD10S, not the ZD10.

---

5. Radikal RK14S: Best Verified Budget Option

💰 ~£40–£60 |🏆 Sold Secure Motorcycle Gold |🔊 120dB alarm |📌 14mm double-locking pin |⚖️ ~620g

The Radikal RK14S is a fully hardened stainless steel alarmed disc lock that appears on the Sold Secure approved products list as a currently certified Motorcycle Gold product. At the budget end of this list it delivers a strong specification: a 14mm locking pin that matches the Oxford Boss for raw pin diameter, a double-locking mechanism that secures at both ends of the pin, and a 120dB alarm with motion-sensitive warning beeps before the full alarm triggers.

The lock cylinder uses a disc detainer core with rotating armour, anti-drill and anti-pick protection, and a security key identified with a unique code so duplicates can be requested without having to send the lock away. That level of cylinder specification is typically found at a higher price point and reflects well on the overall product. The independent alarm module and CR2 battery are easily replaceable, which is a practical detail that matters for a product intended for long-term outdoor use.

The alarm activates in two stages. Motion triggers six warning beeps first, and if the disturbance continues the full 120dB siren fires. This staged response reduces false alarms from passing traffic or wind while still catching a real attempt early. The lock body is a rotating armour design that resists drilling and direct attack on the keyway.

It is widely available on Amazon and verified on the Sold Secure database, which is the key check for any security product recommended on this site. For a rider who wants a 14mm double-locking alarmed disc lock with a current Sold Secure Gold rating at an accessible price, the RK14S is a well-specified option.

Verdict: 

A well-specified, currently certified Sold Secure Gold alarmed disc lock at a budget price. The 14mm double-locking pin, staged alarm, and anti-drill cylinder make it a credible option for riders who want verified independent certification without spending over £60.

---

Quick Comparison

Lock	Price Range	Sold Secure	Alarm	Pin	Best For
Abus Granit Detecto XPlus 8077	£100–£130	Gold + Thatcham	100dB, 3D sensor	13.5mm	Best overall, insurance recognition
Oxford Boss Alarm	£55–£75	Gold + Thatcham	100dB	14mm	Mid-range, widely available
Xena XX15	£120–£160	Gold	120dB, dual sensor	14mm carbide	Premium, high-value bikes
Zovii ZD10S	~£45	Gold	120dB	9.95mm carbide	Best value
Radikal RK14S	£40–£60	Gold	120dB	14mm double-lock	Budget, verified Sold Secure

Things Worth Knowing Before You Buy

Check your disc hole size first

This is the most common avoidable mistake with disc locks. The pin needs to pass through a ventilation hole in the brake disc, and the hole needs to be large enough to accept the pin diameter. Most modern motorcycle discs will accept a 10mm pin without issue. A 13.5mm or 14mm pin requires a larger hole, which most modern full-size motorcycles have but older bikes, scooters, and some smaller machines may not. Measure or check your bike's disc specification before ordering a lock with a larger pin.

Use the reminder cable every single time

Riding off with a disc lock fitted is genuinely easy to do, particularly in the morning or when distracted. The consequence is an immediate, expensive stop and likely damage to the brake disc, calliper, and possibly the fairing. A reminder cable stretched from the lock to the brake lever or handlebar makes it physically impossible to ride away without noticing. If your lock does not include one, buy one separately. They cost a few pounds and save a potentially costly mistake.

Fit the disc lock to the front disc when possible. Some riders fit disc locks to the rear disc because it is more accessible. The front disc is the better choice for two reasons. The front brake is more powerful, meaning the lock resists forward movement more effectively. And a thief attempting to wheel the bike out of a space will typically push from behind, which means the front wheel hits the resistance first and makes the attempt immediately obvious.

An alarmed disc lock is not a substitute for a chain

A bike secured only with a disc lock can be lifted into a van. The alarm will sound in the transit, but that does not help you. An alarmed disc lock works best as part of a layered setup: a chain through a ground anchor provides immobility, the alarmed disc lock provides noise and adds a second point of attack required. The two together are considerably more effective than either alone.

The layered approach: For outside storage, the recommended combination is a ground anchor, a Sold Secure Gold or Diamond chain, and an alarmed disc lock. Our motorcycle security on a driveway guide covers the full layered setup in detail. Each layer removes one attack method available to a thief. Read our guides to the best ground anchors and the best chains and locks for the full picture.

Declare the disc lock to your insurer

An alarmed disc lock declared on your insurance policy, particularly one with a Sold Secure Motorcycle Gold rating or Thatcham approval, will typically reduce your premium. Include the brand, model, and rating when declaring security. For maximum insurance recognition, the Abus Granit Detecto XPlus 8077 and Oxford Boss Alarm are the most consistently cited products by UK motorcycle insurers due to their Thatcham approval alongside the Sold Secure rating. Our guide to motorcycle insurance for bikes stored outside covers exactly what to declare and which insurers recognise Sold Secure and Thatcham approval.

Battery maintenance

Alarmed disc locks are battery powered, and a flat battery means a silent lock that provides no noise deterrent. Most use a CR2 or similar lithium battery that lasts well under normal use, but it is worth checking the battery annually and replacing it as a matter of routine rather than waiting for it to fail. Some locks provide a low-battery warning beep; others do not. Check your lock's manual for the battery type and replacement procedure before you need to do it in a hurry.

How to fit

1. Choose the front disc as your default fit. The front brake disc gives the lock a more secure position between the fork leg and caliper, and provides greater resistance to forward movement. Switch to the rear only if your front disc geometry prevents a secure fit.
2. Locate a ventilation hole that accepts your lock's pin diameter. On most modern motorcycles a 10mm or 14mm hole is standard. If the pin doesn't pass through cleanly, don't force it — check another hole or consult your bike's disc specification.
3. Insert the pin fully and press the lock body closed until you hear it click locked. Give it a firm tug to confirm it's seated properly. A half-locked disc lock gives a false sense of security.
4. Attach the reminder cable. Loop one end around the brake lever or handlebar before you walk away. This single step prevents the most common and expensive disc lock mistake: riding off with it fitted.

If your lock includes a reminder cable, attach it before you walk away every single time. Riding off with a disc lock fitted is a genuinely easy mistake — the cable makes it physically impossible to forget.

FAQs

Q1: What is the best alarmed disc lock for a motorcycle kept outside?
For a motorcycle stored outside or on a driveway, a Sold Secure Gold-rated alarmed disc lock with at least a 13.5mm pin is the recommended minimum. The Abus Granit Detecto XPlus 8077 is the top pick for outdoor use because of its Thatcham approval, 3D position sensor (which reduces false alarms from wind and cover movement), and corrosion-resistant body. For the best value option, the Zovii ZD10S offers a 120dB alarm and carbide-reinforced pin for under £50, with independently verified outdoor performance.

Q2: Do alarmed disc locks reduce motorcycle insurance premiums in the UK?
Yes — most UK motorcycle insurers apply premium reductions for a Sold Secure Gold or Diamond-rated disc lock declared on the policy. Thatcham-approved locks carry additional weight with some insurers. The Abus Granit Detecto XPlus 8077 and Oxford Boss Alarm are the most consistently recognised by UK insurers due to their dual Sold Secure Gold and Thatcham approval. Always declare the specific make, model, and rating when getting quotes.

Q3: Should I fit an alarmed disc lock to the front or rear wheel?
The front wheel is the better choice in most cases. The front brake disc sits in a more secure position between the fork leg and caliper, the front brake provides more resistance to forward movement, and a thief pushing the bike rearward-first will encounter the locked front wheel immediately. Fit to the rear wheel only if your front disc geometry prevents a secure fit, this sometimes applies to scooters and smaller-diameter discs.

Q4: Will an alarmed disc lock stop a lift-and-load theft?
No — a disc lock goes with the bike if it is lifted into a van, and the alarm sounding in the back of a transit does not stop the theft. An alarmed disc lock's purpose is as a noise deterrent that raises the risk for the thief and forces any attack to happen loudly. For genuine resistance to lift-and-load, pair the disc lock with a Sold Secure-rated chain through a ground anchor. See our guides to the best ground anchors and the best chains and locks for the full layered setup.

Q5: What pin size do I need for a motorcycle disc lock?
Most modern motorcycle discs will accept a 10mm pin without issue. Larger 13.5mm and 14mm pins require a correspondingly larger ventilation hole — most modern full-size motorcycles have this, but older bikes, some scooters, and smaller machines may not. Check your disc ventilation hole size before ordering. A larger-diameter pin resists bolt cropper attack more effectively than a smaller pin of the same material, which is why Sold Secure Gold-rated locks tend to use 13.5mm or 14mm pins.

Q6: How loud is a 120dB motorcycle disc lock alarm?
120 decibels is roughly equivalent to a pneumatic drill at close range — it is clearly audible from inside a house and from neighbouring properties at that volume. Most alarmed disc locks are rated between 100dB and 120dB. Anything at 100dB or above will be disruptive enough to deter a casual or opportunistic thief. The Xena XX15, Zovii ZD10S, and Radikal RK14S on this list all reach 120dB; the Abus Granit Detecto and Oxford Boss are rated at 100dB but produce a noticeably clear, sustained tone rather than a thin beep.

---

Found this useful? The rest of the site covers motorcycle security for riders without a garage in more detail, including the best ground anchors, the best chains and locks, the best motorcycle covers, and insurance for bikes stored outside.