Lezyne KTV Pro Alert Drive

The Lezyne KTV Pro Alert Drive is a neat and compact rechargeable rear light with an Alert function that works like a brake light, using accelerometers that change the light output when you are slowing down, and again when you are stopped. Generally it works well, with a simple but very good tool-free mount, but run-times don't quite match those quoted, and daytime visibility isn't as good as some.

The KTV Alert puts out a maximum 75 lumens and has five modes – three flashing (including daylight) and two constant – plus the Alert, which is always on.

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The Alert feature functions like that on the Lezyne Zecto I've also been testing: accelerometers detect when you are slowing down or braking and change the output to a brighter constant light; when you come to a stop it changes again to give out a series of flashes that are brighter than any of the standard flashing modes, and in a different sequence.

It comes at a £5 premium over the non-Alert KTV, and unless you have circumstances where its settings might be frowned upon – perhaps regular group rides (you can't switch this function off, as you can with the Zecto) – I think the extra cost is worthwhile as it does seem to be noticeable.

Following drivers and riders confirmed that it worked – they noticed it changing modes – and particularly noted the stop function, which is very visible. You can see it in action in the video below.

As with the Zecto, although the Alert function worked as expected and activated at all times when slowing down, this did also include times when I was slowing but not actually braking, such as the beginning of a steep slope. It also occasionally came on while riding at a constant speed – seemingly when rolling over a hump in the road.

Also, as I mentioned in the Zecto review, while the change in output might be noticeable, how effective it is is hard to say, as many won't know what it's signalling. Then again, if it gets motorists' attention that can only be a good thing.

Constant and flashing

The headline 75 lumens is only for a single setting, the daytime flash, and doesn't strike me as being bright enough. It's not as bright as some we've tested on road.cc, including the Zecto Alert, and while it is visible – in clear daylight up to around 300 metres away – it lacks any real punch to help it stand out.

Likewise, at 25 lumens the high constant mode, Blast, isn't as powerful as the Zecto's, but at night it's bright enough and clearly visible.

The lowest constant setting, economy, is just 5 lumens, which I think is too dim to be used on any public road, day or night, though it might be of use on a path or trail where there is no motor traffic. The more powerful constant setting is bright, but not dazzling at night.

Of the flashing modes, both 30 lumens, the 'standard' Flash is useful and bright enough, visible beyond 300 metres, with a long quoted run-time of 10hrs 30mins. The other, Strobe, has a shorter run-time and is less punchy, and doesn't strike me as being as useful.

Design

The style of light and casing gives a very broad angle of view from behind, and the quoted 270-degree wide angle visibility seems about right.

Run-times

Lezyne gives these run-times:

• Daytime – 7hrs 30mins
• Flash – 10hrs 30mins
• Strobe – 6hrs 30mins
• Blast (constant) – 4hrs 30mins
• Economy (constant) – 14hrs

I tested the run-time of the Blast mode several times and unfortunately it fell short on each occasion, lasting between 3hrs 45mins and 4hrs 10mins. Note that this was inside in the warm and stationary, so the Alert setting wasn't being activated at all; given the bright flashes that produces, it will undoubtedly reduce run-times if activated frequently (as Stef found with the Lezyne Strip Alert Drive), and cold winter weather might also affect battery life.

Charging

Lezyne doesn't provide a recharge time, but from empty it was showing as solid green to indicate fully charged in just under 2 hours, which is very good given the run-times, and makes recharging at work easy if you commute (in normal times).

Charging is via the KTV's USB connector, hidden under a rubber cap. It plugs directly into a computer or wall socket, which is quick, easy and convenient, although personally I prefer using a cable attached to a plug.

The major drawback for me is that the rubber cap comes off completely and might be easy to lose. It would be handy if Lezyne could add just a small loop onto both with some sort of tie connecting them, to ensure they stay together while charging.

On the plus side, it's easy to see whether the rubber cap is correctly in place, to ensure the light is protected from water ingress.

Mounting

The KTV is likely to be attached to a seatpost on most bikes, and the stretch within the rubber strap provided is excellent for the job. It's robust and will stretch around even the deepest aero posts.

It even comes with a small adapter that flattens the mount further, for seatposts with a wider flat section. I think this is a really nice design feature, and one area where the brighter Zecto Alert is lacking.

It held the light stable, both on and off-road; I would have complete confidence in the light and its USB cover staying in place.

Value

The KTV's rrp of £30 is pretty good considering its Alert function, but there are others with similar technology around this price. Shaun has been testing Magicshine's Seemee collection – £25.99 for the Seemee 100 (full review imminent), £31.99 for the Seemee 180 and £33.99 for the Seemee 200. 

Looking at his thoughts on both the 180 and 200, the lights themselves are good, but the braking function is less impressive than the Lezyne's.

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Higher up the tree, Exposure's TraceR ReAKT, which David tested and rated highly, is double the price of the KTV at £59.99 – and only has the braking function not the stop mode the Lezyne Alert lights have.

If you're not bothered about the Alert feature there are brighter lights available for less, such as Giant's excellent Recon TL 100 for £25 and the Recon TL 200 (£35), both of which impressed the riders testing them.

Conclusion

Overall, the KTV is a bit of a mixed bag. The Alert function works well and I think is worth the extra £5 over the standard light, it performs well at night with good wide visibility, and it'll fit all seatpost styles. However, the daytime flash isn't as bright as some, and it didn't hit the claimed run-times by a fair amount, which is something to be aware of when using.

Verdict

Compact and powerful enough for night time with useful Alert function, less good in daytime mode and missed claimed run-times