Fatbike fork for Dynamo hub

This fork is for loaded dirt, snow &/or sand touring once attached to his Surly Necromancer frame. It’s got more braze-on’s than most touring frames! It’s got three bottle bosses on each leg for Salsa Anything cages or for water bottle cages in one of two positions (high/low). It’s got one bottle boss on the middle of each leg and a threaded nut in the lower steerer tube for a Salsa Minimalist Rack. It’s also got one bottle boss at the dropout just in case he wants to use another type of low-mount pannier for bringing more stuff, or a fender perhaps. The last thing this fork has is internal routing for SON (Dynamo) hub wiring which will connect to a Supernova E3 light at the fork’s crown (which doubles as the upper attachment for the Minimalist Rack).

The internal wiring is less complex than it sounds, I just made a hole in the lower inside leg, brazed on the seen cap to protect the wire as it comes out of the leg and goes down to the hub’s tongs. I fed some bailing wire from that exit hole up through the crown BEFORE brazing the sleeve to the lower leg of the fork which made it super easy to fish through the crown. This wire stayed in place for the brazing and then the powdercoating and then I used the wire to guide some derailleur cable-housing liner through the fork leg to serve as the path for the light’s wire. The plastic housing will also protect the wiring from the edges of the fork crown. The wire will momentarily poke out the bottom of the steerer and attach to the E3 light itself. Hopefully Scott will send some pics of it all set up!

It’s an interesting fork that he requested because he wanted clearance for 4.7″ tires on a Clown Shoe (100mm wide) rim. Most fatbike forks that run this sized tire have 135mm axle spacing or even 170mm. Since the SON hub and other Dynamo hubs don’t come in that width we made this fork with the normal 100mm axle spacing.

The fork is built pretty beefy. The crown pieces are 1.125 diameter x 0.058″ wall since they are so long compared to a regular segmented fork. The sleeves and legs are the normal setup, sleeves are the same as the crown pieces and the legs are 1″ diameter x 0.035″ wall. Paragon hooded dropouts and a modified Willits ISO disc tab and there you have it. The color he chose closely matches the text outline on the Necromancer frame but also makes it stand out a bit from a standard black fork.

3 Responses

  1. Nice fork. What is A-C measurement?
    What is your opinion on 1″x0.035″ fork legs, looks like you’re using them on many of your forks?

    • That fork used the same specs as the non-offset Pugsley since it was going on a Necromancer Pug: 447 atc and 43 offset?

      I really like the ride of the 1×0.035″ lower legs. They have a nice flex to them and I like building with the upper “lugged” sleeves. I know many others use straight 1.125 x 0.035 with some kind of support or gusset at the crown and that works great too, and is less work.

  2. Thanks for the info!

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