The frame is here, the wheels are built, and the cranks are on. Unfortunately, it’s going to stay in that state for somewhere between the next 2 days and 1.5 weeks.

There were a couple snafus with the components arriving correctly, hence the partially built bike. The two that are stopping the show right now are a SRAM I-motion 9 shifter and the fork. Bikeman.com somehow didn’t get the fork in the box with the frame, so they’re sending it out, and AZ Bikes forgot to order the shifter for my internal hub, so that’s on its way as well.

Here’s what the final build list is shaping up as:
Frame and Fork: Surly Big Dummy
Front Wheel: Surly Bolt-on 25h Disc Hub laced to a Sun Rhino Lite XL rim
Rear Wheel: SRAM I-motion 9 Internally Geared Hub (20 tooth cog) laced to a Sun Rhino Lite XL rim
Crankset: Shimano LX converted to 32 tooth singlespeed (replaced big ring with bash guard to help save my pants)
Stem/Seatpost: Ritchey Comp
Handlebar: Surly Torsion Bar
Brakes: Avid BB7 Road brakes with Cane Creek flat top levers
Headset: Cane Creek S8
Tires: Kenda K-rad 2.3” (rear), Geax Mezcal 2.1” (front)
Seat: Unknown GT seat

As you can see, there are a few new parts and a few used or somehow acquired parts (like the mismatched tires and the handlebars). Should be pretty nice

One of the ‘newer’ items for me is the internally geared hub. As we all know by now, I’m pretty adverse to gears in most situations, but I decided if I’m using the big dummy to it’s full 400 lb capacity, gears may be useful essential. As I’m still a fan of the singlespeed look, the internally geared hub was the obvious option.

As part of my research into hub options, I did a little calculating on where I would end up with a gear ratio range so I could pick my front ring size appropriately. I assumed that the wheel and crank size were the same as a mountain bike (which they are, so it’s not so much of an assumption as an observation). So, to compare the i-motion hub to a moutain drivetrain, we can simply look at the gear ratios.

If we take for a quick example a 11-32 rear mountain cassette with a 22-32-44 crankset on the front, the easiest gear ratio is 0.69 (22-32), and the hardest is 4.00 (44-11).

Turns out that the i-motion 9 hub has a lower gear ratio (just from the hub) of .542 and an upper of 1.844. This is just the gearing in the hub, so you have to multiply this by whatever gear ratio I choose for the ‘singlespeed’ drivetrain which will push the hub. The hub comes with a 20 tooth ring on the back, so I looked at 32 and 34 tooth front rings. The 32 gives a range of 0.87 (1.6×0.542) to 2.95 (1.6×1.844). The 34 is a little harder, but not far off, with a range of 0.92 to 3.13 (the 1.6 changes to 1.7).

In the end I ended up with the 32 tooth since I’m planning on needing to haul some weight with this bike. That puts my final gearset at the following theoretical range:

I-9 Gear RatiosEffective Ratios
1.8442.95
1.6112.58
1.3752.20
1.1721.88
11.60
0.8531.36
0.7271.16
0.6210.99
0.5420.87

Hopefully that’ll get me up the hills and still allow some high speed cruising.