Thanks guys
There's plenty to consider there, mostly that there are options beyond the expensive (relatively) Hawk lamps.
The HID option is good but there's are always nights in December with a wet road, heavy oncoming traffic and a smeared visor when the only thing that helps are more lamps. They do seem to be popular on many of the 1200GS's I've seen. I will experiment.
Thanks very much for these posts.
John
What would be useful to know is what you are trying to achieve by way of lighting improvement?
Conspicuity day/night
Low beam night riding
High beam night riding
I read most of the threads on lighting trying to work out which options improved all three.
I was fixed on the HID route until I read the threads about HIDs burning the reflector (even the 35w versions). It seems to make a lot of sense to use the flood pattern on the OEM light but with more light form an HID and no extra bits sticking out waiting to get broken and very little wiring to do or switches. Although I have never used HIDs I suspect if you are prepared to replace the headlight unit at some point in the future it may still be an easy option but not the cheapest in the long run.
The problem I found is that few people on the threads can really convey what a particular light option is really going to do for you and what it will do to oncoming vehicles - equally important IMO if you don’t want to get dazzled by irritated motorists who flash you if your dipped lighting is too bright - it is counter-productive.
Also few manufacturers show you what the 3D beam pattern is going to be (Denally LEDs are an exception but that is only 2D beam pattern). You need to know this particularly for the dipped lights. What does a 10 or 30 degree beam really mean in practice? It is not just the beam pattern it is also where you point them and how high you mount them which makes them more or less useful for high of low beam use.
I experimented with some cheap LED lights with a flood pattern
see this thread.
I can recommend dimmable LEDs although they don’t offer as much low beam benefit as I had hoped for - the dim level has to be set too low to avoid dazzling oncoming vehicles or the lamps angled too low to benefit high beam.
You need to decide how much of your winter commute can be ridden with high beam. Zen Overland is a good starting place to look for LEDs and they do a dimmer which will be better than the one I used (though without as many brightness settings). LEDs are getting cheaper and/or more powerful all the time so look around.
If you want high beam improvement with aux lights you have to tap into the high beam circuit and probably use relays powered from the battery if you want high powered LEDs, although some have lower powered units through the canbus circuit.
As for mounts the Rugged Roads mount is what I used and its great - you dont get much of a triangular pattern with the headlight - with the low indicator position. Other options you could consider are to get steering damper brackets to mount on the fork tubes. Bear in mind the fork tubes are tapered from 53-57mm so the size you get will depend on how high you want to mount them. You should be able to get some for £20 each off ebay. Zen Overland do some KTM ones which are £108 for a pair

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One final word of caution - having a high beam that throws light 150m down the road is great until you find you are driving at a speed suitable for 150m for forward vision and then suddenly have to switch to low beam with 20m of forward vision - I still get caught out. At least with the OEM lights you get much the same forward visibility in my experience - a perverse safety feature!