I ♥ Forumslader

Bit overdue post. Since 2014, when I planned to ride a bit longer it was clear from the beginning, that I'd ride for most of the time wheelsets with SON dynamo hubs. Simply because these are the best ones out there. Running the old barrel-shaped SON28 on the trekking bike for quite a few years there was really just one thing to decide, going with the SON28 or the SONdelux?

After going trough a few articles from https://fahrradzukunft.de and a nice exchange with Jens from http://www.forumslader.de/ I opted for the SON28. The little bit heavier one is the better choice if you wanna be on the safe side when it comes to running both consumers - the Forumslader and the lights. For the lights I went with the EdeluxII and combined it with the very sexy Supernova Taillight (read more here).

The whole setup more or less is still the same, the first two wheelsets (32h) were built by Felix and his colleagues. Bullet proof work horses, never let me down. Probably a bit outdated because "so small" rim width, but nice all year round wheels, one set with GP4000sII for the summer, one set with 4Seasons for the winter.

The EdeluxII from 2014 became replaced by the upside-down-version since it gave me the little but needed space for the small finger on the aero extensions. Latest wheelset is a Reynolds DiscBrake Assault LE. On that I took out the front hub and put in the SON28 12 disc center lock. Since that was the only option to match the 24h it is set up with the 12/9­mm axle-adapter to match the old school drop outs.

Thus I can switch all wheels between all bikes and all Forumslader between all wheels and bikes as well. I always built the Forumslader for being fitted inside the fork shaft. Normally not a big deal, when it comes to carbon forks a bit tricky. Their inner diameter is really small, since the carbon requires a reasonable wall thickness.

The Forumslader - as it name says - is a result of a discussion started by users of the rad-forum. I once had an account there, but I like the outdoorseiten more, especially since it covers not only bicycle stuff. So, with the question how to provide electrical power to charge whatever device you carry while travelling by bike with the onboard generator - the dynamo hub - the first sketches and layouts were developed. It all started with a simple layout containing a board to solder all required parts onto. With the time the board became much better designed, removing wired bridges, reducing size and finally coming as a prebuild board with SMD-type components on it. So generally you don't need any special skills if you start with a latest versions. As a further development the idea of an Ahead-version came up. Basically a board and assembly layout just small enough to fit inside a fork shaft. Since most of the bikes used by the people active in the rad-forum were steel or aluminum bikes the maximum width of the board was set to approx. 23mm. And that's where it gets interesting. With the carbon fork of my GF02disc I only got ~22something mm inner diameter. Which means I'd need to take off a bit on each side of the circuit board. Just enough that it will fit snug into the shaft. Another thing is to run the cables going to the Forumslader and coming from it out the fork shaft on the top side - since it's a carbon fork. most metal forks on trekking bikes are open on the bottom end of their shaft pipe - easy for running cables in and out while keeping the Forumslader safe and dry. So I had to get a suitable expander  and tweak it in a way the cables can run trough. Finally the top ahead set spacer needed to be drilled too.

My first one was a version 4, with the Efest V2, 18350 type, with 12V output and a 3xAA charger. It actually did it's job - until not. It got a short circuit in on of the cables and was damaged in the end. I'd say it was my fault not the Forumsladers design itself. So I ordered and received a spare assembly just in time before TCR2014, thx @Jens again - you saved my Transcon there :-). I took it off the BMC and on my trekking bike, with the steel USB-aheadset-spacer, running input cables downwards now.

The BMC got a version 5 and Efest purple. Running smooth and doing it's job just fine. Since I build up another GF02disc for long distances I got 2nd one, with 3A output on USB - which got burned during a its first test run last years early spring. I did not seal the cable properly since I wanted to make sure everything works fine. Had planned to seal everything just after that 800km-test ride. But - if something can go wrong - it goes wrong. Weather forecast promised differently before, but I ended up in a heavy thunderstorm with heaps of downpour. I was busy to find shelter myself and forgot about the Forumslader. In the end it got soaked and I had to get another set of parts. Learned it the hard way.

But generally - I really don't care about the time I spent on building them up or digging on the web for a nice cable and so on - it's worth it because it gives me the freedom to not need to stop just for charging somewhere or carrying always a power bank as backup. The whole thing is just perfect - also in comparison to commercially available alternatives (123456 & 7).

So what's next? Another little piece of my cockpit needs a hack - and the prototype is being tested at the moment....

...if it works all well, the final version will get another post.

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