Marc’s fatbike

Marc’s fatbike

My friend Marc is an former road pro, who taught me a lot when we raced together. I lost my training buddy when he moved back to Maine, but he hasn’t lost his competitive spirit and has had fun with the winter fatbike race series there. He asked if I could build him a new race bike – I have been wanting to build a fatbike for ages, so was excited for this project!

Like me, Marc prefers to keep his Q-factor as low as possible. Fatbikes now mostly use a 197mm rear end spacing, and have a corresponding wide crank spindle to match the chainline. We opted to use the 177mm standard, to bring his feet 20mm closer together. But this created a bit of a challenge to fit the 27.5″ x 4.5″ tire, chainstay and crank/chainring into a very limited space. Marc asked for a 34T chainring too, and we wanted to keep the chainstays as short as possible. I suggested an elevated chainstay, but Marc wasn’t keen on that aesthetic, so I had to get creative with a custom yoke to effectively have a very thin chainstay section to squeeze through the gap. This did the job and kept the chainstay length at 445mm.

In considering cable/hose routing, trying to do external routing and keep the cable hugging the frame around the tire was going to get a bit messy. And with the yoke there isn’t a way to do internal routing through the lower half of the frame. So I created custom seatstays that shoot into the toptube, enabling straightforward and clean internal routing directly to the derailleur and caliper. These were a little challenging with four bends in two different planes……

Up front we have the Lauf Carbonara suspension fork, plugging into an oversize headtube. The toptube is ovalised along it’s length, and the downtube is ovalised at the BB to increase the stiffness.

The weight comes in at 27lbs, although 7lbs of that is the tires! It is rare to have snow here in the valley, but appropriately enough there just happened to be on the day of photographs :- Looking forward to seeing how Marc gets on with it.


  1. beautiful, as usual 😉

    “I suggested an elevated chainstay”
    what would that bring to the table? what would have been different?
    (sorry for my english, hope you understand my question)
    thank you!

    best regards,

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