The best Bike alarms, compared.
Top pick: WANGCL 110 dB USB alarm Best value: Mengshen 113 dB mini alarm – Best value among strap-on units with a large sample, score 88 at about £12.62, 4.5 from 5,266 ratings. Updated 20.10.2026.
People buy one so a bicycle, e-bike, motorbike, or mobility scooter makes a noise if someone moves it while they are still nearby. The twelve listings say 110 dB or 113 dB, with no measurement distance in the files. Check that the remote arms, that you can turn sensitivity down, and that you will keep the power topped up. The [bike alarm buying guide](/hub/burglar-protection/bike-alarm/sub/bike-alarm-buying-guide) sets out type, power, mounting, and the water claim before the brand names. A bike alarm, on this amazon.co.uk shelf, is almost always a battery siren with a vibration sensor and a key fob. One listing is different: a keyed disc lock that also sounds. The siren does not lock the bike, shows no Sold Secure grade in these files, and does not locate the bike.
People buy one so a bicycle, e-bike, motorbike, or mobility scooter makes a noise if someone moves it while they are still nearby. The twelve listings say 110 dB or 113 dB, with no measurement distance in the files.
42 products checked · 58 hrs invested · +24,600 readers
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Personal buying guide
Question 1 of 2
What should the unit do?
The WANGCL is a 120 g, 110 dB USB-rechargeable remote alarm at £14.99. Across 39 amazon.co.uk ratings it averages 4.7, the highest star line in the set. The stored file has seven UK reviews, and they are short praise: good quality, loud, very sensitive, used on a mobility scooter, and the writers would buy it again. Remote range, sensitivity steps, water resistance, and cell capacity are not stated. No repeated criticism appears. With seven texts that means the complaints have not been written down, not that the unit has been proved over a season. At this price the Mengshen and the Cruxer AAA already have hundreds or thousands of ratings and named limits. A 4.7 on 39 ratings is not a reason to treat this as the top pick.
Pros
Cons
Best for: Only a light USB siren for a scooter if you already accept a tiny written sample.
Less suitable: Any choice that depends on a stated range, an IP code, or a long UK review trail.
Specifications
Common questions
Is a remote included?
Yes. The listing says a remote is included.
What remote range does the listing give?
None. The range field is missing, so it is not stated.
How many ratings are on the extract?
39 at 4.7. The stored file holds seven UK reviews, which is too small to treat 4.7 as settled.
The Cruxer KS-SF32R is a 110 dB remote alarm you charge by USB-C, with a stated 4.2 V 700 mAh cell, seven sensitivity levels, an IP65 claim, and a nylon bracket plus strap and tape. Across 1,413 amazon.co.uk ratings it averages 4.6, and the 50 UK reviews praise the loudness, the charge, and fitting it to a motorbike without wiring into the bike battery. The range is not one figure: 70 m in the details and 229 ft in a highlight. One reviewer said the bracket twists off if it is not screwed down. Another found the siren very quiet after a few months while the three volume steps were still showing, saw no obvious fault, and bought another. High sensitivity also triggers when nobody is near the bike. At £19.99 it is the rechargeable unit with a real review file, as long as the body is fixed so it cannot be twisted off and pocketed.
Pros
Cons
Best for: Someone who wants a rechargeable siren and will screw the bracket to the bike.
Less suitable: A buyer who wants the 17,273-rating trail, or a pin through a disc brake.
Specifications
Common questions
Does the bracket model use replaceable AAA cells?
No. The listing specifies USB-C charging and a built-in 4.2 V 700 mAh battery.
What is the stated remote range?
The details field says 70 m. A highlight also prints 229 ft, which is about the same distance. Treat it as one claim, not two tests.
How does it mount?
The listing gives a nylon bracket, a strap, and double-sided tape. Screw the bracket down. A reviewer said it twists off if it is not fixed.
The Cruxer 22R is a 130 g, 113 dB alarm on three replaceable AAA cells, with volume steps at 96, 106 and 113 dB, seven sensitivity levels, an IP55 claim, three ringtones, and an SOS mode that sounds if the bike tilts past 45 degrees and is off by default. Across 672 amazon.co.uk ratings it averages 4.6. Fifty UK reviews call it loud, easy to fit, and already in use on mobility scooters, and several call the small remote well made for the money. The listing disagrees with itself on range: the details field says 20 m, while the bullets say 50 m or 164 ft as a lab detection distance. Instructions confuse people until they are read carefully. High sensitivity includes a report that jet-washing a car set the alarm off. Battery life was still unknown to early reviewers, and one person replaced the alarm cells and then the remote cell after the unit stopped responding. At £13.99 it is a clear AAA option beside the dearer USB-C Cruxer, with a shorter proof of how long the cells last.
Pros
Cons
Best for: A scooter or bike owner who wants replaceable AAA cells and an optional tilt siren.
Less suitable: Anyone who needs one trustworthy range figure, or who will arm it before reading the card.
Specifications
Common questions
Does this Cruxer alarm include a remote?
Yes. The listing says the remote is included and gives two range figures: 20 m in the details field and up to 50 m or 164 ft in the bullets.
How is the Cruxer 22R powered?
It uses three replaceable AAA batteries. The listing claims up to one to three months of daily use. Early reviews do not establish how long the cells last.
Is a tilt alarm switched on?
The SOS tilt mode, past 45 degrees, is listed as off by default until you turn it on.
The Getsuna is a 120 g, 113 dB remote alarm at £11.99, the lowest price in the set, with a metal plate and strap, adjustable volume, and a 25 m range claim. Sensitivity steps, water resistance, and power are not stated, and the details show no warranty. The rating is 4.6 from three amazon.co.uk ratings, and the saved listing holds one UK review whose title calls it a wireless alarm and whose text marks it loud. That is not a pattern of use. At £12.62 the Mengshen has 5,266 ratings for a similar strap-on job, so the pound saved here buys an unknown. It may still make a noise if that single review is typical. You should not read 4.6 from three ratings as a settled result, and you should not skip a separate lock because this unit was the cheapest siren on the page.
Pros
Cons
Best for: A spare only if the price is the whole decision and a failed unit is easy to send back.
Less suitable: A main overnight alarm, or any comparison that treats three ratings as a test.
Specifications
Common questions
How many ratings support the 4.6 score?
The listing line shows three ratings. The stored file contains one UK review. That is not a settled result.
What is in the box?
Alarm unit, metal plate, mounting strap, remote control, and a user manual.
Does the listing state a water-resistance code?
No. Water resistance is not stated, and the details show no warranty.
The Wsdcam SF22R is a 113 dB vibration alarm with seven sensitivity levels, an IP55 claim, and a remote the listing puts at 66 ft. Across 17,273 amazon.co.uk ratings it averages 4.5, the longest trail in this set, and the 32 UK reviews mostly call it extremely loud, easy to fit, and useful as a deterrent, including for a courier. One long-term user reported a low-battery alert and no trouble over two months. The remote does nothing until it is paired, and that setup is called annoying. Rain set one unit off when it was fitted under a car bumper, so a bike left in a downpour can do the same if sensitivity stays high. At least one later unit was called poor on sensitivity after earlier purchases had been fine. At £16.99 it is the top pick when you want a strap-on siren judged on how many people have actually used one, and it still does not lock the wheel.
Pros
Cons
Best for: A commuter who wants the longest UK review trail on a strap-on siren and will pair the remote before the first night.
Less suitable: Anyone who needs the alarm to pin a brake disc, or who will leave sensitivity high in heavy rain.
Specifications
Common questions
What remote range does the Wsdcam listing state?
66 ft, about 20 m. That figure is a listing claim, not a measured street range.
What waterproof claim is printed?
IP55, with seven sensitivity levels and three volume levels. The code is a listing claim, not an independent certificate in this file.
How many amazon.co.uk ratings are on the extract?
17,273 at 4.5, the longest trail in this set of twelve.
The Mengshen is a 72 g alarm, 65 mm by 45 mm, with a 113 dB claim, an IP55 line, seven sensitivity levels, six bell sounds, a finder chirp, and a remote the listing puts at 15 m. Across 5,266 amazon.co.uk ratings it averages 4.5. In 50 UK reviews people call it very loud for the money, easy to hide under a bike cover, and a reasonable choice on an MT-125 because it does not drain the bike battery. A light knock or lifting a cover can set it off, and one reviewer said a garden broom did the same. The disarm chirp is loud, with no quiet option mentioned in that review. Instructions are a little hard to follow, and the sample does not show one repeated hardware failure. At £12.62 it is the best value strap-on siren here if you will turn the sensitivity down, and you should plan around 15 m rather than a 70 m claim from a dearer listing.
Pros
Cons
Best for: A budget bike or small motorbike where a light siren and a large review file matter more than USB charging.
Less suitable: Anyone who needs a quiet disarm, a long remote range, or a pin through a brake disc.
Specifications
Common questions
How large is the Mengshen unit?
The listing gives 65 mm by 45 mm and a weight of 72 g, the lightest body in this set.
What remote range is stated?
15 m, with arm, disarm, and a one-key finder. Plan around that figure rather than a 70 m claim from a dearer listing.
What waterproof claim is printed?
IP55, on a PC shell. That is a listing claim. It does not mean the sensor ignores rain if sensitivity stays high.
The NineLeaf KS-SF22R is a 130 g, 113 dB remote alarm with an IP65 highlight, a 20 m range claim, and a two-year warranty. Across 594 amazon.co.uk ratings it averages 4.5. Fifty UK reviews call it loud and very sensitive, people use it on mobility scooters and bikes, and some report reliable triggering and then buy a second unit. The details table does not name the cells; one reviewer using three AA Duracell cells reported about 50 to 60 days, and less with a local brand. On a second purchase the remote failed to connect while the siren itself still sounded, and another fob stopped working after a couple of months. At £13.99 the warranty is longer than the one year on the Cruxer AAA, but the remote is the part that fails in this sample. Sensitivity steps are not stated.
Pros
Cons
Best for: A scooter user who wants the IP65 highlight and a two-year warranty, and who can cope if the fob dies.
Less suitable: Anyone who needs the remote to be the reliable half, or who wants seven sensitivity steps printed on the listing.
Specifications
Common questions
What remote range is in the details?
20 m. That is a listing claim.
Which machines does the details field name?
The compatible-devices field says scooter. The highlight also names a motorcycle, bicycle, tricycle, car, door, and window.
What warranty is stated?
Two years, longer than the one year on the AAA Cruxer. The remote is the part that fails in this review sample.
This Cruxer is a 180 g, 113 dB alarm on two replaceable AA cells, with seven sensitivity levels, an IP66 claim, a red flashing light, strap and tape, and a remote the listing puts at 196 ft. The listing also claims up to one to two years of daily use from those cells, which the 21 written reviews do not confirm. Across 27 amazon.co.uk ratings it averages 4.5. The reviews call it easy to install, loud, reasonable quality for the money, and already used on a motorcycle. The repeated weak point is the remote, which one reviewer called a shame on an otherwise acceptable budget alarm. Another said it was not a credible deterrent. At £15.99 the IP66 line and the flash are the extras over the £13.99 Cruxer on AAA cells, on a review count that is still too small to treat 4.5 as settled. No warranty is stated in the details.
Pros
Cons
Best for: A motorcycle owner who specifically wants the IP66 line and a flashing light and can live with a small sample.
Less suitable: A commuter choosing on review count, or anyone already wary of budget remotes.
Specifications
Common questions
What batteries does this Cruxer use?
Two replaceable AA cells. The listing claims up to one to two years of daily use. The 21 written reviews do not confirm that span.
What is the waterproof claim?
IP66, the highest water mark printed in this set. It is a listing claim.
What does the red light do?
The listing says it flashes at three-second intervals.
The REAPP PC1406 is a keyed 110 dB alarm disc lock weighing 420 g, with no radio remote, two keys, a carry bag, LR44 cells (12 in the box, six fitted), a 1.5 m reminder cable, and a two-year warranty. Across 9,595 amazon.co.uk ratings it averages 4.4. Fifty UK reviews call it loud for the size, easy to press and lock, and a visual deterrent used beside another lock, and some long-term users say it holds up in the rain. Batteries run down quickly in the comments. Reviewers describe it as a cheap disc lock whose siren is the point, and as a weak lock if it is the only thing on the bike. One scooter user called it overpriced after a drop damaged it. At £28.98 it is the only product in this set that passes a pin through a brake disc. The saved listing does not claim Sold Secure, so it is not a substitute for a graded lock your insurer named.
Pros
Cons
Best for: A disc-brake bike that already has a stronger lock and needs a noisy visual layer on the rotor.
Less suitable: Rim brakes, a Sold Secure grade named by an insurer, or anyone who wanted a pocket remote.
Specifications
Common questions
Does the REAPP lock include a remote?
No. The details field says the remote is not included. You arm it with the key, not a fob.
What does the 1.5 m figure refer to?
The box list includes a 1.5 m reminder cable. It is not a wireless range. It is there so you do not ride off with the lock still on the disc.
Which bikes can it fit?
The listing says vehicles with a disc brake the lock can pass through, including motorcycles, mopeds, and bicycles. It does not fit rim brakes.
The Fosmon 51087HOM is a 113 g, 113 dB alarm with seven sensitivity levels, three volume levels, an IP65 claim, an SOS siren if it tilts past 45 degrees, and a remote the listing puts at 230 ft. Across 6,694 amazon.co.uk ratings it averages 4.4, the second-largest sample of a strap-on unit here. Fifty UK reviews praise the loudness, batteries that are included so there is no wiring, arm and disarm tones, and quick fitting under a motorcycle seat or on an e-bike. The battery-cover screw is very small, and replacement is described as a nightmare. It does not always trigger on the first small movement; one reviewer needed a firmer push. A windy tarp was a poor place to stick it, a garage was fine, and a reviewer says to use tape and cable ties together because a light stick-down can be pulled off. At £17.99 it is the large-sample IP65 and SOS choice, with a fiddlier battery door than the AAA Cruxer. Cell chemistry is not in the details table.
Pros
Cons
Best for: A motorbike or e-bike where you want SOS tilt and a long review file, and you will use ties as well as tape.
Less suitable: Anyone who hates small screws, or who treats the 230 ft line as a measured street range.
Specifications
Common questions
Does the Fosmon alarm include a remote?
Yes. The details field says a remote is included, with a maximum range of 230 ft, about 70 m. That is a listing claim.
What waterproof claim does the listing make?
IP65. Use tape and cable ties together. A light stick-down can be pulled off.
What does the SOS function do?
The listing says it sounds if the vehicle tilts more than 45 degrees from the position it was armed in.
The Tawveml is a 130 g, 110 dB USB-C alarm with a brake light, seven sensitivity levels, an IP65 claim, tilt detection, and a remote range printed as 70 m or 229 ft. The listing claims about one to three months from a three-to-five-hour charge. Across 370 amazon.co.uk ratings it averages 4.4. Of 46 UK reviews, people praise the combined rear light, instructions they could follow, a bright lamp, a quick charge, and buying a pair for two mobility scooters. One buyer called the unit tiny, with fiddly parts, and returned it. Another called it a waste of money. Several early reviews said road testing was still ahead, so the light-plus-siren idea is better documented than long nights outside. At £20.99 it is the dearest strap-on unit in this set, and the lamp is the reason to pay that instead of the Cruxer USB-C at £19.99.
Pros
Cons
Best for: A mobility scooter where one housing should be both the rear light and the siren.
Less suitable: A bike that already has a rear light, or a buyer who wants the Wsdcam review trail.
Specifications
Common questions
Is this alarm USB rechargeable?
Yes. The listing says USB-C, with a claim of one to three months from a three-to-five-hour charge. Treat that span as a slogan, not a measured result.
Does the listing include a light?
Yes. It describes a brake light that comes on after braking. That lamp is the reason it costs more than the USB-C Cruxer.
What waterproof claim is printed?
IP65. It is a listing claim, not proof the sensor ignores rain.
The Qumox KS-SF22R is a 160 g, 113 dB alarm with an IP55 claim, seven sensitivity levels, three search ringtones, a remote the listing puts at 66 ft, and a box that includes the alarm battery, a remote battery, a screwdriver, a manual, two cable ties and two stickers. Across 194 amazon.co.uk ratings it averages 4.4. Only 11 UK reviews are stored, and they are mostly short praise: it does what it should, it is good for the cost, and it has been used as a scooter alarm and a bike alarm. No repeated criticism appears in those 11 texts. That is a thin sample, not a clean long-term record. A listing question about a low-battery indicator is unanswered, and the cell chemistry is not stated. At £13.99 it matches the Cruxer AAA and the NineLeaf on price while offering far less written evidence than either.
Pros
Cons
Best for: A buyer who wants ties in the box at £13.99 and accepts a short written sample.
Less suitable: Anyone choosing on review depth, where the Wsdcam and the Mengshen are clearer.
Specifications
Common questions
Is a user manual in the box?
Yes, plus a screwdriver, two cable ties, and two stickers. The alarm battery and the remote battery are listed as included.
Does the listing confirm a low-battery indicator?
No. The question appears on the page and the bullets do not answer it, so it is not stated.
What remote range is stated?
66 ft, about 20 m. That is a listing claim.
Twelve amazon.co.uk listings were scored on 19 October 2026 from the listing files and the review notes kept for this category. There is no lab test and no measured decibel check. A printed 110 dB or 113 dB figure is a listing claim. The four weights below sum to 100. A large review sample outweighs a tiny one at the same star line.
Amazon stars and review count
40%About 40 points. A 4.6 from three ratings does not outrank a 4.5 from thousands.
Fit for the stated job
30%About 30 points for siren versus a pin through a disc, stated sensitivity, a water claim, and a power source you can name.
Price against that job
20%About 20 points, in GBP, for the shelf price against the job the listing actually describes.
Review themes
10%About 10 points, applied as deductions for pairing trouble, false alarms, twist-off mounts, flat fobs, and short cells.
Match the alarm to the job before you compare the decibel line. Eleven of these twelve amazon.co.uk listings are vibration remotes. One is a keyed disc lock. Prices in the extracts run from about £11.99 to about £28.98. A siren does not lock the bike, and a star rating does not measure thefts prevented. If you will still be nearby, a remote siren can make a noise. If you need the wheel pinned, only the REAPP in this set does that, and it is not a graded lock.
A bike alarm, on this amazon.co.uk shelf, is almost always a battery siren with a vibration sensor and a key fob. One listing is different: a keyed disc lock that also sounds. People buy one so a bicycle, e-bike, motorbike, or mobility scooter makes a noise if someone moves it while they are still nearby. The siren does not lock the bike, shows no Sold Secure grade in these files, and does not locate the bike. GPS trackers and Thatcham systems are not among these twelve ASINs.
A vibration remote only makes a noise. The REAPP pins a disc and reviewers still call it a weak lock if it is the only thing on the bike. None of these twelve shows a Sold Secure grade. Lock, mark, and register the frame as well.
Reviewers report brackets that twist off and stick-down mounts that pull away. Use ties as well as tape, or a bracket that needs a tool. The factory setting is often the most sensitive. Wind, a cover, rain, and a jet wash appear in UK reviews when it stays there.
110 dB and 113 dB have no measurement distance in these files. IP55, IP65, and IP66 are listing claims, not proof the sensor ignores rain. Battery lines of months or years are not confirmed by the review samples. One Cruxer listing prints both 20 m and 50 m.
Start with the type. A vibration remote only makes a noise if someone moves the bike while you are still nearby. An alarm disc lock also stops a disc-brake wheel rolling. Neither chains the bike to a stand, and neither is a GPS tracker. In this set the remotes are the plastic bodies from 72 g to 180 g. The REAPP is the 420 g keyed lock, with no radio remote and a 1.5 m reminder cable. Then look at how it stays on the bike. Tape plus cable ties, or a bracket that needs a tool, beats tape alone.
Seven sensitivity steps are common, and you set them while the alarm is disarmed. The factory setting is often the most sensitive, which is why a cover, a broom, wind, rain, and a jet wash show up in UK reviews. NineLeaf, WANGCL, and the REAPP do not state a step count. Getsuna only says adjustable. Power is a habit, not a slogan. The AAA Cruxer uses three AAA cells. The flash Cruxer uses two AA cells. USB-C on the dearer Cruxer is a stated 700 mAh cell. Tawveml is also USB-C.
Three typical situations, each with a recommendation from this comparison.
You want a strap-on siren with the longest review trail, and you will still use a proper lock. The Wsdcam scores 91 at about £16.99, with 4.5 from 17,273 ratings. Pair the remote before the first night. It does not lock the wheel.
You want a light siren and a large review file more than USB charging. The Mengshen is 72 g at about £12.62, score 88, with 4.5 from 5,266 ratings. Turn the sensitivity down. The claimed remote range is 15 m.
You want a noisy pin through the rotor, not a pocket remote. The REAPP is the only disc lock in this set, 420 g at about £28.98, with 4.4 from 9,595 ratings. The saved listing does not claim Sold Secure.
The top pick is the Wsdcam 113 dB remote alarm, score 91, at about £16.99. It has the longest review trail in this set, 4.5 from 17,273 amazon.co.uk ratings, with seven sensitivity levels and an IP55 claim. Pairing is awkward until it is done, and rain has set a unit off. It does not lock the wheel. The best value is the Mengshen 113 dB mini alarm, score 88, at about £12.62, with 4.5 from 5,266 ratings. The 15 m range claim and the loud disarm chirp stay in that score. Getsuna at about £11.99 is cheaper and is not best value, because the file has three ratings.
Mengshen 113 dB mini alarm
Best value among strap-on units with a large sample, score 88 at about £12.62, 4.5 from 5,266 ratings.
Editorial
Peter F. is the editor for DIY & tools at productscompared.co.uk. Comparisons in this category are checked against amazon.co.uk listings, review evidence and public UK sources.
Guides on what to look for, how to use a product, and common mistakes.
Public UK sources listed in the research digest. Listing prices, stars, and review counts are from the amazon.co.uk extracts for this category, checked on 19 October 2026.
Expert source (DIY & tools): Charlie White (Charlie DIYte) (external profile) – public expert commentary used as a research source, not as a contributor to our pages.
This page contains affiliate links to amazon.co.uk with the tag pcuk26-21. If you buy through them, we may earn a commission at no extra cost to you. Prices, stars, and review counts are the UK listing lines used for this comparison. We did not run a lab test.
