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Cateye Viz 100 Rear Bike Light



Good for most riding contexts but the strap could be improved
Four sensible modes
Reasonable run-times
Memory function
Mount strap could be improved
No clothing/luggage tab

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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The Cateye Viz 100 is a bright rear light with four modes and an auto kick-down, should you get caught out. It's generally capable and likeable; the only thing I'm not completely sold on is the mount's strap.


The light's Opticube lens promises 300-degree visibility, and is also designed to be equally effective mounted vertically or horizontally. It's made from polycarbonate and employs collimator technology to direct the three diodes' output most effectively.

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IPX4 for weatherproofing is on the low side but not uncommon, and perfectly adequate for road-biased riding.

The 3.7V 500mAh lithium-Ion cell is reckoned to handle 300 charge cycles before performance begins to taper off, so a good couple of years' continual use. It charges via micro-USB, with a snug-fitting cover keeping things dry. The cable is a little short for my tastes, but easily substituted.

2021 Cateye Viz 100 Rear Bike Light - charging port.jpg

The switch is a clear, rubbery affair, requiring a definite press. It's easily found and operated wearing full-finger gloves, and once on, singular presses course through the modes. A memory function, defaulting to your last choice, is super-convenient, and there's a battery life indicator integrated within the switch, too.


Cateye has taken some interesting routes on this front in recent years, not all of them meeting their potential. This one's called the SP-15; essentially, an aero seatpost-compatible block into which the light slots. It can be mounted horizontally or vertically.

2021 Cateye Viz 100 Rear Bike Light - mount.jpg

The ladder strap hooks into lugs either side, and I've had no issues with standard round profiles between 25.4 and 30.8mm. It's compatible with some box-section trailer tubing and helmets, too.

Although functional and reliable enough, it's a bit fiddlier than others, especially in the dark. Exchanging it for an oversized o-ring type improved matters.


The four modes are: Daytime Hyperflash, 100 lumens (15 hours); Constant, 15 lumens (5 hours); Flashing, 10 lumens (70 hours); and 'Group Ride', a pulsing 35 lumens.

Group ride is interesting and possibly a misnomer. I don't know about anyone else, but wheelsucking 35 lumens isn't my idea of a good time. I can see the relevance if you're at the back, but it's a bit brash at relatively close quarters. 'Shepherd mode' might be more appropriate.

Get past this and it's proven my default for those lonely lanes I'm so fond of, and far more impressive than the flashing. Following riders and the odd motorcyclist reckoned they could spot me at 200, maybe 250 metres, dropping to 150 metres on a misty 6am blast.

> Buyer’s Guide: 22 of the best rear lights for cycling

There's no missing the 100-lumen Hyperflash, even in strong autumnal sunlight. Friends reckoned they spotted it at 300 metres (nearer 400 on overcast days and towards dusk). The distinctive, retina-tickling tempo has been a godsend when the mists unexpectedly drift across the fields.

Positioning it vertically has a small but palpable edge, especially at junctions, negotiating roundabouts and just performing turns in the road – particularly so when I've tethered it to my low-slung trailer. Though it has a smaller surface area than I'm usually comfortable with attaching to a trailer or tagalong, the daytime mode more than compensates, especially in such contexts.

Group ride is also a surprisingly good choice for these duties. That said, something like the Knog Cobber Mid Rear Light is a superior choice for nocturnal couplings, but a good deal dearer, too.

Back on a solo, the 10-lumen flashing is better than I was expecting and the numbers might suggest. It's assertive enough for town, in common with the Cateye Rapid Micro Rear LED, but a bit tame – or at least I felt less conspicuous – on faster sections of unlit road.

Bargain on being visible at 125 metres (about the length of a football field) on a clear night, dipping to 80 when it's cloudy.

The 15-lumen steady is up to the job of built-up areas; I seemed to register on friends' radars at 70-80 metres.


Ours has proved very faithful to the cited run-times in temperatures between 7 and 15°C.

I've only just cruised past the 50-hour mark with the 10-lumen flashing – it's laughably frugal and shows no sign of faltering. In the other three modes, auto kick-down (to flashing) strikes when reserves hit 10%.

Charging times are similarly faithful: 3 hours from a laptop, 15 minutes faster at the mains. That's longer than some, especially those using USB-C, but on a par with other, such as the Sigma Blaze. Plugged into a dynamo USB it's a bit more variable, but has gone from zero to hero in just over 4 hours.


Minor niggles aside, the specification and performance are favourable and the price is good, although there's still a fair bit of competition.

Oxford's Ultratorch Slimline R50 Rear LED doesn't have a daylight running mode and the insert is less robust than some, but at £17.99 it's a good bit cheaper.

Topeak's Redlite Mega Rear Light comes in at £26.99 – slightly more but very bright and it runs from replaceable batteries, which might lack the outright convenience of a rechargeable but can be a godsend if you're on a long ride, and replacement AAAs are cheap and widely available. Just don't lose the casing screw.

Magicshine's Seemee 100 is also a little more at £28.99, offers seven modes (three steady, four flashing), a braking mode that can be switched on and off, and also meets IPX6 for weatherproofing.


The Cateye Viz 100 is a good rear light that covers most bases well. The only thing that merits some revision, to my mind, is the strap.


Good for most riding contexts but the strap could be improved test report

Make and model: Cateye Viz 100 Rear Bike Light

Size tested: 100 Lumens

Tell us what the light is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Cateye says "Cateye: 100 lumens of affordable power and runtime in a lightweight compact body. Compact, bright, and versatile, the all new ViZ100 rear bicycles light stands out with great visibility from the OptiCube™ lens technology and Daytime Hyperflash™ mode in an economical package. A fully featured rear light, the ViZ100 (Which replaces the previous best selling Rapid Mini), comes with 4 settings including a group ride mode and flashing mode which gives an impressive 70 hours of runtime. The innovative new Snap System™ bracket is simple to fit and place on your preferred position on the bike. The ViZ 100 with its 100 lumen high power makes this the ultimate rear bike light to give you confidence wherever or whenever you ride."

Tell us some more about the technical aspects of the light?

Cateye lists:

3 LEDs (100 lumens)

Focused lens for maximum visibility

Highly visible during daytime

Superior 300 degree visibility

Long rear beam projection

OptiCube™ lens technology

Lithium-ion rechargeable battery

USB rechargeable (Micro-USB cable included)

Low battery indicator

4 modes: Constant / Flashing / Group Ride / Daytime Hyperflash

Mode memory function

Battery Auto Save (The mode automatically changes to flashing when the battery power gets low.)

New seat post bracket SP-15 which also fits contemporary (Kammtail) aero seatpost

Snap System™ bracket

Designed in Japan


Constant (15 lumens):5 hrs

Flashing (10 lumens):70 hrs

Group Ride (35 lumens):11 hrs

Daytime Hyperflash (100 lumens):15 hrs

Charging time (From empty) : 3 hrs



Our proprietary OptiCube™ lens technology maximizes brightness for greater visibility.

Snap System™

Allows riders to place rear lights on various locations in both horizontal and vertical orientations.

Side Visibility

Provides 300° visibility from the side to increase safety.

Low Battery Indicator

Alerts when remaining battery gets low.


Can be used in the daytime.

All Weather IPX4

Can be used in rainy weather.

Rate the light for quality of construction:

Feels reassuringly solid and has stood up to some torrential downpours without missing a beat.

Rate the light for design and ease of use. How simple was the light to use?

Simple to use, even wearing winter-weight full-finger gloves.

Rate the light for the design and usability of the clamping system/s

Quite versatile; no issues with standard seatposts and box section type tubing. However, I found the ladder-type strap fiddlier than others.

Rate the light for waterproofing. How did it stand up to the elements?

IPX4 is fairly basic on paper, but in practice I've had no issues, even through some torrential rain.

Rate the light for battery life. How long did it last? How long did it take to recharge?

Very practical for most contexts. To date, run-times are within a few minutes of those cited and the same goes for charging.

Rate the light for performance:

On balance, a very practical light for most riding contexts, offering decent output, battery life and charge times.

Rate the light for durability:

I haven't spotted any obvious weak spots while testing, so with basic care there's no reason to think it won't serve riders well.

Rate the light for weight:

At 46g it's heavier than some, but nothing I'd lose any sleep over.

Rate the light for value:

Specification and performance are favourable, although there's still a fair bit of competition around this price point.

Tell us how the light performed overall when used for its designed purpose

There are brighter models and some better sealed from the elements, but the switch is user-friendly and the choice of settings are assertive and yet very practical. The 10-lumen flash is a little underpowered for darker, faster sections, but elsewhere, quite eye-catching. Run-times have been within a few minutes of those cited, the Hyperflash is extremely potent and the 10-lumen flash, super frugal.

Tell us what you particularly liked about the light

Good selection of modes that are appropriate for most riding contexts, favourable run-times and charge-times.

Tell us what you particularly disliked about the light

I found the ladder-type strap fiddlier than some. A minor niggle rather than a dislike, really.

How does the price compare to that of similar products in the market, including ones recently tested on

It's a decent price, but there's a fair bit of competition, as I've mentioned in the main review.

Did you enjoy using the light? Yes

Would you consider buying the light? Yes

Would you recommend the light to a friend? Yes

Use this box to explain your overall score

It's a good light that covers most bases, though I'm not completely sold on the strap.

Overall rating: 7/10

About the tester

Age: 48  Height: 1m 81cm  Weight: 70kg

I usually ride: Rough Stuff Tourer Based around 4130 Univega mtb Frameset  My best bike is: 1955 Holdsworth Road Path and several others including cross & traditional road

I've been riding for: Over 20 years  I ride: Most days  I would class myself as: Experienced

I regularly do the following types of riding: cyclo cross, commuting, touring, fixed/singlespeed, mtb,

Shaun Audane is a freelance writer/product tester with over twenty-eight years riding experience, the last twelve (120,000 miles) spent putting bikes and kit through their paces for a variety of publications. Previous generations of his family worked at manufacturing's sharp end, thus Shaun can weld, has a sound understanding of frame building practice and a preference for steel or titanium framesets.
Citing Richard Ballantine and an Au pair as his earliest cycling influences, he is presently writing a cycling book with particular focus upon women, families and disabled audiences (Having been a registered care manager and coached children at Herne Hill Velodrome in earlier careers)

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zero_trooper | 2 years ago

I've no problem with ladder style bands, they've got to be better than the Knog thin O rings. However, if I was in the market for a rear light I would want the versatility of a deep clothing/luggage tab (Is that what they are really called Shaun?).

Simon E replied to zero_trooper | 10 months ago

I've just fitted a Viz 100 to my race bike. It's brighter than I expected for a 'bottom of the range' £25 model. smiley

The ladder band seems strong and plenty adequate. I have happily used the Cateye rear lights for many years with the SP-6 seat post bracket. Since the Viz range use Cateye's classic square mounting block, I could swap back to that if I prefer it to the band attachment.

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