Project FatBike

Inspired by some recent fatbikes I saw in London I decided I simply HAD to have one, although I wasn’t going to be doing any beach or snow rides in the near future I like the idea of being able to ride it absolutely anywhere, particularly since I live close to Epping Forest. This want for a fatty wasn’t helped much by seeing one regularly popping up in Holborn and me having to walk past it during my lunch breaks. I then got an opportunity to try a fat tyred beach bike at Critical Mass London and it was quite frankly, majestic.

FatBike sighted in Holborn

After doing a bit of research I saw a lot of different models coming on to the market but leaned more towards an established brand with a bit of history and experience in making these types of bikes. Bring on The On-One Fatty. It’s a great looking bike and the geometry looked superb not just for loose terrain but it looked like it might be a lot more versatile and may even be suitable for some light on-road use too. There were a few things about the stock setup which bothered me though, the wheelset weights were rather high and the 2×10 drivetrain seemed cumbersome and unnecessary. When I discovered the On-One Fatty frame was available on its own my mind was made up, I was going to do a complete DIY build using the Fatty V2 frame and fork. I’ve always had in the back of my mind that I wanted to do a complete self-build some day, my servicing and mechanical skills were pretty well honed but building something up from scratch gets you a lot more involved and gives a really clear understanding of every single component. I’m pretty sure I can now handle any servicing requirement I may ever have from now on.

The First parts to arrive were the Floater tyres, tubes, seatpost, clamp and saddle. This was a horrible teaser as to what I could expect as it took another 2 days for the frame to arrive… Damn this thing is big! I had to sit it next to my trusty roadbike for a scale comparison!



It took a long time to decide on the drivetrain, I originally intended to have a 1 x 9 setup with a 40t front but quickly spotted that there was not enough frame clearance for a chainring any bigger than 32t, I could have gotten away with a 34t in the outer chainring position but this would have needed a fiddly chainguide and still produced a terrible chainline in the smaller gears. In the end I went for a raceface crankset with their superb narrow/wide 32t front ring and a Shimano Ultegra 10speed cassette on the rear. This produced a near perfect chainline when coupled with the raceface 100mm bb and provides a wide gear range capable of handling anything I was likely to experience in London and the local trails.

With that decision made it was time to spec all of the other components and order a wheelset with a Shimano Hub. I had planned originally to have some wheels built up but while searching for rims I spotted Triton cycles had a sale on and the Halo Tundra wheelsets had a very good offer on them. The specs looked great so I bit the bullet and hit the order button.

Parts List:

Component Model
Frame On-One Fatty V2 18″
Forks On-One Fatty Forks
Seatpost On-One Twelfty Seatpost 31.6mm Black
Seatclamp On-One forged QR seatclamp
Saddle WTB Volt On-One Edition Black
Wheel Set Halo Tundra 135/170 fatbike wheelset
Tyres On-One Floater 4″
Inner Tubes On-One Floater Tubes
BB & Crankset RaceFace fatbike crankset bb170mmx100mm
Chainring Raceface Single narrow wide 104bcd 32T
Bash Guard FSA Gravity 32t polycarbonate bashguard
Chainring bolts RaceFace chainring bolts black
Chain Shimano Ultegra 6701 10spd 116lnk silver
Pedals DMR V8 Magnesium flat pedals white
Brake Calipers AVID BB5 160mm
Brake Levers Avid FR-5 Stubby MTB
Brake Cables Eclat Core Orange
Brake Light Meilan X5 wireless brake light
Cassette Shimano Ultegra 6700 10spd 11-28
Derailieur Shimano Deore XT M786 Shadow Plus 10spd medium cage
Shifter Shimano Deore XT M780 Rapidfire pod Right
Gear Cables Shimano RoadGear Set white outer
Headset spacers LifeLine Carbon headset spacer kit
Cable donuts LifeLine 10x pack black cable donuts
Grips RaceFace Half Nelson Lock-On Grips Orange


Given I wasn’t sure exactly how the bike would handle and only had very limited experience of riding a fatbike I didn’t actually make a handlebar/stem decision. I decided to use a spare carbon fiber 590mm bar and carbon stem which I had lying around and to make a decision later on as to whether I would keep them or buy longer bars. With all the parts set there was only one thing left to do… Build it !


The Result



There was only really one hiccup, the Halo Tundra wheelset was built with rear spacing for the disc brake rotor, whereas the Fatty forks have front spacing. This took a bit of planning to get around and I ended up having to file down the IS post mount adapter to stop the brake caliper from rubbing the rotor. This wasn’t ideal but the strength hasn’t been compromised and now there’s enough clearance for the brake to clear the rotor and operate normally.


This post was first uploaded a year ago, I have now had the fatty for 18 months and every time I even go near it, it still manages to put a smile on my face. It has proved a lot more versatile than I ever expected and now gets use for so many different types of rides it is hard to keep track, from Critical Mass London and iBikeLondon’s relaxed pace group rides, to epic 100mile adventure rides, not to mention the daily city commute, I have yet to find something the fatty can’t do.


Getting the wheel Trued at Jason’s Workshop – Stepney City Farm

Being “that guy” on the train after riding from West Ham to Windsor

After Party with iBikeLondon

Some festive lighting for the iBikeLondon halloween ride

Lights still going strong after the party ends

Waiting for everyone else to turn of for a pizza outing


TJ Stamp

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