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Kryptonite Street F-450



An affordable and dependable medium strength light suitable for commuting and general low-light riding

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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A capable front light that sits nicely in the mid-priced commuter category, with decent battery life and simplicity on its side, the Kryptonite Street F-450 has proved a useful companion as the nights draw in.

  • Pros: Simple to use, decent battery life, battery indicator
  • Cons: Slightly fiddly to tighten strap on oversize bars

This offering from Kryptonite sits between the Street F-250 and the recently tested Alley F-650 in its Street Light series.

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Out of the packaging, which includes an adjustable handlebar clamp, instructions and USB cable, the light is compact and reasonably light, with a matt grey and black all-plastic textured finish, with the USB charge point underneath a rubber cover, and a transparent rubber cover over the button on the top. Helpfully, and the reason it is see-through, is that the light uses a multi-colour LED in a traffic light sequence of green-amber-red to indicate the remaining battery power.

Kryptonite Street F-450 - top.jpg

The F-450 has six modes: full, medium and low steady settings, a daytime and night-time pulse, and flashing.

Using the light on local (mostly lit) roads, I found the pulse modes useful for just being seen in overcast daylight conditions and dusk. My old rear light is permanently set to its pulse mode as it's what I prefer, so I was pleased to find these modes on the F-450.

On low, medium and high the beam pattern is quite focused, with a small spread of light outside the beam. It's fine for urban riding, but even on high it's not powerful enough for unlit lanes unless you lower your speed substantially, so look for a higher output light such as the F-650 if that's your main type of riding.

The side ports on the light are useful, a little larger than many of these smaller units, giving decent side visibility when crossing junctions and the like.

Kryptonite states the run-times as 2 hours for the highest output and 24 hours for the flashing, with varying times in between for the others. I tested the high output mode a few times and it lasted just over two hours, so lives up to the claimed time. The other modes were used varyingly, but nothing made me doubt they wouldn't run for at least the stated times.

The light as mentioned helpfully gives you an idea of the battery life via the coloured button on the top, green indicating 100-50%, amber 50-25% and red under 25%. I did find that it dropped from green to amber in around 20 minutes in high output, but then sat at amber for quite some time before dropping to red with around 15 minutes left – so not entirely accurate, but enough to know when it's really low and may be worth swapping to a lower setting – which, if you leave it long enough, the light does by itself.

> Buyer's Guide: The best 2017/2018 front lights for cycling

Charging times were average for a lower output light, with a few hours needed if charging at work from a laptop USB, but around two hours using a wall charger. I used a Samsung fast charger but I don't think it makes much difference. Of note, though, is that it is a sealed unit – once the batteries have outlived their working life, they cannot be swapped, as with some lights on the market.

Fitting the light to a bike is via a chunky bracket and strap. On my oversize bar it was easy enough to position but a little fiddly to get really tight, with not a lot of strap to pull on to get it really tight. Once done, though, it was nice and secure. The light then drops on at an angle and clicks in at the back, with a push release to take it off again – quick enough for you to bother even on short stops for security.

As a mid-range commuting light that won't break the bank, the F-450 is a decent option that should last a good many seasons. It compares well with other options in the 450-lumen range, including the more expensive Knog PWR Commuter retailing at £49.99 but with lower run-times (review to come), and the cheaper NiteRider Swift 450 retailing at £38, but again with lower run-time modes and fewer modes, making the F-450 an attractive buy.


An affordable and dependable medium strength light suitable for commuting and general low-light riding test report

Make and model: Kryptonite Street F-450

Size tested: 450 lumens

Tell us what the light is for

An affordable, USB chargeable front light with good run-times, ideal for urban commuting.

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

Kryptonite lists:


FULLY USB RECHARGEABLE - No batteries to buy or replace

Run time up to 24 HOURS

Side illumination ports allow cyclist to be seen when riding across traffic lanes

Memory Function-Light turns on at the last mode it was turned off

Power saving function- 10% power or less, lights will automatically switch to lowest lumen output

Built in battery indicator- Red illumination = lower than 25%, Yellow = 50% - 25%, Green = fully charged

Rate the light for quality of construction:

It's a solid enough unit, well put together with an all-plastic case and simple design.

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

You can't go wrong – clip the light to the bike, and a single illuminated button on the top switches on and off, and between the six different lighting modes. The USB charging port is on the underside covered with a rubber flap.

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

The clamp is a fairly chunky unit, with a ratchet strap to tighten. This allows easy fitting to either standard or oversize bars, but can be difficult to get tight as you may need that extra 'click' with only a short bit of strap to pull on.

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

During testing it saw a reasonable amount of rain and muck thrown up from riders in front and didn't suffer any issues at all.

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

Kryptonite claims up to 24 hours on the flashing setting and 2 hours on the highest 450-lumen output. The top setting was pretty much spot on – I got just over 2 hours a couple of times, and on the lower steady settings it ran all week on shorter evening rides without needing a charge. Charging is simple enough, taking a few hours on a laptop connected cable, and around 2-3 hours on a wall socket fast charger.

Rate the light for performance:

For a 450-lumen light it performed as expected, not dazzlingly bright on darker roads, but just about usable on pitch black country lanes if speed was reduced accordingly. Perfect for lit roads and ideal for urban commuting.

Rate the light for durability:

It's stood up to the rubbish weather we've had, and being chucked in a bag or a jersey pocket with no issues or damage.

Rate the light for weight:

It's a small unit and doesn't run a separate battery pack and as such, doesn't weigh too much at 153g, the clamp negligible.

Rate the light for value:

At £44.99 retail (and cheaper in reality), it's on par with its competitor 450-lumen equivalents and for a quality light from a respected brand is a good buy.

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

The light performed perfectly well to my expectations – it wasn't going to turn night to day but it made sure I was seen and, if I rode to the conditions, that I could see. It also never ran out of juice and has been reliable.

Tell us what you particularly liked about the light

Its small size and simplicity; easy to pop in a jersey pocket before leaving the house.

Tell us what you particularly disliked about the light

On the odd occasion the rubber cover on the top on/off/mode button would stick down, meaning I couldn't change the setting. After a short while it would free itself, but not ideal if you wanted a higher output on an unlit road. The clamp is fiddly too – once on and adjusted it's fine, but if you needed to reposition or swap between bikes it takes longer than I would want to get it set right.

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 doesn't break new ground or have fancy features, but its simplicity, usability and relatively low cost help to recommend it.

Overall rating: 7/10

About the tester

Age: 46  Height: 190cm, 6'2  Weight: 185lb, 84kg

I usually ride: Boardman AirPro Di2  My best bike is:

I've been riding for: 10-20 years  I ride: A few times a week  I would class myself as: Expert

I regularly do the following types of riding: road racing, time trialling, cyclo-cross, commuting, club rides, sportives

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