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136g (including wire and reflector) Black (as tested) £83.99

Trelock’s LS905 Bike-I Prio is, on the face of it, a pretty straight-forward, if powerful, dynamo-powered font lamp. However, it is built to a high standard, looks good (in my opinion), with hints towards a more retro style, produces pretty impressive illumination. Price point is toward the top of its bracket, but I have seen significant reductions on-line.


Pros: Well-made, straight-forward, decent price.


Cons: Instructions could be clearer, be nice to have a headset bracket.



Trelock’s LS905 is an 80 lux lamp in a competitive market. Similar to their LS906, which comes with remote control and two light settings, there’s also an sibling,. The LS905 is really the LS906 with the frills taken away, leaving a well-made, punchy, uncomplicated front-light.


Made from anodized aluminium, the case comes in a variety of colours – though not as extensive as Son’s Edelux range - it’s enough to keep me happy. Inside a mirror projects the output of a single diode. 80 lux is toward the top-end of dynamo output, and some suggest that 30 is plenty for suburban riding with the odd venture into the sticks. You will find 100 lux on some product lists.

Trelock LS905 Bike-I prio dynamo front lighthub bottle test review seven day cyclist

All German lights conform to Germany’s pretty stiff road traffic rules. We’ve all been blinded by some ill-directed master blasters. Well, that should not be possible in Germany. Nothing more than 200 candela is permitted above the centre point of the lamp, whatever the output of the light. On the same front, there’s a clip-on reflector that snaps into grooves under the main lamp. Of course, there’s a standlight, too.


Needless to say, expect the beam to have a bias to the right. Some may find this a nuisance or even a deal-breaker depending on how speedily you carve into sharp left-hand bends. I’ve learned to live with it. However, I’d not say it’s as pronounced as some. Even then, with a fork mount, a slight adjustment can mitigate any issue.


The trend toward hub dynamos continues amongst more demanding cyclists, but there are still plenty running bottle dynamos for financial, aesthetic, or other reasons. The LS905 will work with both, so long as they’ll produce 6v. Initial concern that resistance would be too much on the bottle dynamo proved unfounded – probably a tribute to modern technology.


Switching on and off is done with a small rubberised button that glows blue when things are running. This actually switches between being on and relying on the automatic sensor to activate and deactivate.

Treloc dynao LS905 light lap tet review



Ours came with Trelock’s standard fork mount bracket. A variety of others can be purchased, most usefully one for mounting on the bars, see Michaels’ review of the Trelock LS906 dynamo light. Currently there is no headset/steerer tube mount.




Although the instructions are a bit patchy – especially for newbie dynamistas - getting the lamp fitted and working is pretty straight-forward. Wiring the lamp is a touch fiddly. Selecting the correct terminals, as shown in the instructions, is easy enough. Pressing the small white catches down and sliding the bare end of the wire into the terminal before releasing the catch, is less so – if your fingers are as nimble as mine. Dextrous or not, it’s worth doing this before mounting the light.


Zip-ties and/or a few wraps round the forks and fit it to the dynamo. On that topic, you’ll need to source a length of wire if your hooking up to a dynamo on the rear wheel. In the box you’ll find a wire perfect for a front dynamo, hub or otherwise, with the lamp mounted on the fork, but no more.

Trelock LS905 terminals



Waiting for a repair to my preferred hub dynamo wheel, I thought I’d pair-up the LS905 with a Busch and Mueller Dymotec6 6v bottle dynamo residing in retirement in a draw in the shed. The full beam emerged swiftly, at around five mph. After just a few of rotations a clean white light illuminated the road ahead. The odd flicker, once up to a decent 12mph, can be put down to the dynamo. At sixteen mph things were steady. Zipping along country lanes, there was more than enough light to persuade motorists to dip headlights and to avoid pot-holes. Gentler paced, say ten to twelve mph - gravel/forest road work has been fine, too, but nothing sprightly.


On that topic, 80 lux is a lot of light, so adjustment matters, but this isn’t likely to blind on-comers.

Trelock suggest that the beam is effective to 100m, which seems about right – thpugh in reality 25 metres is nearer the mark when properly adjusted - and visibility around 5500m. In the real world, suffice it to say that car headlights were dipped long before they came around the corner. The beam is strongest at around twenty to thirty metres, sufficient for decent speeds on country lanes.

The beam on ours was rather broader than the I-QX’s, providing a typically German carpet of light on the asphalt. There’s not much of a right-hand bias- rather less than on the IQ-X -, so generally, no pregnant pauses on left-hand bends. Continuing that comparison, the Trelock is a little bulkier, a consideration if space is tight at the mounting point.

There’s a surprising amount of bleed to the sides, creating a sort of halo around the front wheel. Useful in more urban settings and at junctions.

Trelock LS905 dynamo light frnt test revie seven day cylist

Time to hook up to the hub dynamo, in this case a SON 28 6V 3w. Clear light was achieved after a couple of turns of the pedal. A brief initial flicker quickly gave way to a steady, bright light. Performance was identical to when it was on the bottle, but steadier.


Getting used to the control button is worthwhile. Simple enough, it isn’t an obvious click – at least, on the test model, although there is a nice blue glow when engaged.




Fundamentally, this is similar to the LS906, minus some of the sophistication and the control switch. So, great for commute and forays into the night-time countryside. Plenty of light all night long, so worth considering for longer Audax or endurance rides. Real speedsters may want something more powerful, and are probably looking at rechargeable lights with more sophisticated control, or an auxiliary for the darkest of dark corners. I’ll be using this for more leisurely night-time excursions and on the commute along the canal towpath.

Verdict: 3.5/5 A good light for general night-time riding at the higher end of its price bracket, without the sophistication of some.


Steve Dyster




Ryton On Dunsmore

Coventry  CV8 3FH


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