A few years ago I was keen to purchase a bike light. I already owned a Cateye HL1500 halogen light that seemed to attract good reviews in the late 90's. I used this for my night riding at the time which was wholly in the city, as a city boy I did not encounter true countryside darkness. You tend to be unaware of this and still think of night and day, dark and light, yet in the city night was rideable with no lights, they were effectively to be seen by pedestrians and drivers. Anyway time moved on and so did I, 30mls further north into true darkness where stars replace sodium light. One evening I did a favour for a friend and said "oh I'll cycle up I have a light", famous last words it was awful. The Cateye beam was a rectangular slot virtually useless, fortunately the distance was only 4mls round trip but lesson learned.
After this experience I started looking into serious bike lights, the lumicycles, light and motions etc. Most were still halogens but of high power but I resented the price of these and my mind started thinking if it were possible to use a maglite torch. A work colleague poured scorn on my miserly-ness but I started searching the internet and found that others had similar thoughts. I ended off investigating the Fenix range of LED torches, they even had bike mounts so the market was there. I invested my money ( £38 ) into a Fenix L2D shown below.
The output was 180 lumens for around 2hrs in its turbo mode but would give about 5hrs at 100 lumens. This was more than comparable to lights 2-3 times the cost... this was a very good buy. I ventured out into pitch black moonless night and tried each mode finding that low to medium was good for partially lit areas and high for totally unlit.. turbo even more so but to be honest I rarely needed it and battery life suffers. The beam was a spot with a diffuse lower intensity halo narrow but not dangerously so with kerbs and verge visible. The quality of this was excellent and I'm still using it even after a 30mph fall from my pocket, beautifully machined and thoughtfully designed running on AA cells. I can wholeheartedly recommend the Fenix products and their new BT20 bike light looks like another well thought out design ( oh and I'm not paid by them even though it may read that way ). Just before christmas I was very tempted into purchasing the BT20 but I delayed due to other bills to pay and having no income at present. Then 3 months on a curve ball arrived due to the need to replace a wheel rim. My intention was to purchase rim,spokes and build it myself with the purchase of a truing stand. It was during this search that I arrived at the website of Rose bikes Germany. I'd always thought of them as a bike manufacturer rather than component seller but to my shock they sell virtually everything bike related. A look at wheel rims led to wheelsets and then to a single front wheel build...... with a Shimano DH-3N80 dynamo. The rim was a very good Mavic A319 rim in silver all for £63! but I needed a black rim. An email to Rose got a response offering the same build in with black rim. So I now researched reviews on dynamo lights, not common, but Peter White in the US seems to have done a lot of work here. The latest Busch and Muller Luxos looked very good but expensive for the fully featured version, my thoughts turned to the B+M Cyo Premium. This seemed to have a nice beam shape from the B+M flux diagram with around 40-50mtrs of reach and 10m width. I had no idea relative to my Fenix L2D how this would compare but took the gamble and ordered the wheel build, cyo premium light and canti brake bracket. This would all mount onto my Kona Jake in need of new front rim.
Well one week later the box arrived and onto the bike went all the new toys, not without some minor issues described later. The images below show the setup on my slightly muddy bike, well proves it gets used, and the wiring will be tidied later as well.
The niggles I had were with mudguard spacing as the rim though identical in diameter is 5mm wider than previous rim so the tyre position changed slightly enough to touch sides of guard at fork crown. This was rectified and then the canti bracket would not accommodate the torx headed lamp bolt, the bolt is designed around the lamps original thick steel bracket. The canti bracket came with a nut and bolt, not captive or nyloc nut so I didn't wish to use that as I think it would vibrate loose on our shoddy road surfaces. My solution came using two of the spacer washers from a pair of discarded canti brake blocks. This has worked perfectly, see top image, and lets me use the original torx bolt which is pretty solid. I tried to align everything as well as possible prior to test riding.
Now it was time for the exciting bit... or not! Firstly I set off in dusky light and though the light was on you could not see any beam, also no sensation of any drag. As the ambient light turned to true dusk the beam was becoming visible and the darker it got the better the beam became, revealing that it was pretty good. As I got used to this in full darkness I started to think this isn't bad but it's not outstanding, my L2D would probably better it. I thought how can I set the beam as I run to see if it needs a tweak, I stopped and adjust the light down a fraction, retightened and set off again. Wow that really did it, now I was in new territory with a beam in both throw and width beyond the L2D. I must have appeared like a motorbike as a driver waited at an empty junction for me to cycle 200mtrs up to them, not pulling out on me, excellent. I also was able to sit at all speeds, up to 23mph on my test, with no fear of out running the light totally comfortable. The beam wasn't greatly washed out by oncoming cars either and would easily light road direction signs. I did some rough timings to measure the easily visible beam length which gave 6 seconds of beam at 19mph so around 50mtrs of clear bright throw and about 15 seconds of lit road signs at 16mph so around 106mtrs. I'll continue to do further test rides and minor beam tweaks if needed but at the moment it seems very good. There are artefacts in the beam as the reflector is angular but they're not distracting to my eyes and the beam colour I feel is a warmer tint than the L2D. The rim, DH-3N80 build weighed 1.43kg with the full wheel tyre,tube,QR weighing 1.99kg most of weight difference between old wheel being at the hub a 400gm difference. It's early days but I'm very impressed so far and its nice to simply forget about run times and "did I charge my batteries".
So thanks to Rose bikes for very competitive pricing and prompt email responses. The beam pattern of the Cyo Premium is shown below, image taken from B+M's lights flyer.
I think this beam pattern does match my perception of the light on the road with the full width of minor UK rural roads lit ( around 16ft ), plus verge. As mentioned above the throw seems to be about 50mtrs of clear light. The artefacts are more visible dependent on road surface and many times the beam appears more homogenous. To my eyes dusk is when it is more noticeable than full darkness. You can view B+M's tunnel image for the Cyo Premium on their website and see the light and dark areas of the reflector design. The tunnel image, I feel, doesn't really do the height of the beam justice as on the road it lights visibly a lot more. I've now had my second test ride and I'm still seriously impressed. This was undertaken on a cloudy night, no moon, basically pitch black on the rural roads I rode. I had a disturbing experience of a badger running out in front of me and only just clearing my front wheel as I braked hard. I think the extra beam width over the L2D helped me see it earlier than I would have. Don't want any encounters like that as I'm not out to hurt any animals but to see them is nice. So I think for anyone who rides unlit rural roads at night ( not MTB'ing through woods ) I can wholeheartedly recommend the B+M Cyo Premium ( 80 lux, no built in reflector ), together with the DH-3N80 dynamo. I've experienced no dynamo vibration nor had any sense of drag.
Any issues and I'll update this post but hopefully there won't be.
UPDATE:24/11/2014
Just an update now that a new season of darkness has begun. I've found myself regularly caught out by the sudden drop in light on recent rides ( in the UK we put the clocks back 1 hour which has quite an effect ). All I can say is this light is excellent and has already justified its purchase. The freedom of zero battery concerns and the flexibility to light up anytime and also for any length of time is part of my reasoning. The other being the level of light and quality of the beam, yes there are "artefacts" more noticeable at dusk rather than dark but they are pretty minor and the beam simply works for its purpose, unlit country roads and off road tracks( i.e. Sustrans network ). As I passed a dog walker recently he commented "thats a nice light" rather than a complaint about blinding him! Had several non-angry comments of "I thought it was a motorbike coming but couldn't hear the engine" and this has been observed with cars that have waited at junctions rather than pulling out. I've never observed my own light so I'll have to get someone to ride the bike for me and let me see it, I'm now very curious. So in summary for any tourer or winter/commuter bike I'd highly recommend investigating this type of light source, I feel dynamo lights are definitely on parity with battery lights of moderate, useable power. I think the controlled beam pattern is a plus point allowing the lower lumen count to be used to give a good lux count where you need it. Now we just have to educate motorists to keep on top of getting their headlight alignment sorted as well as not driving on full beam, though with this light they dip pretty quickly.
