Fyx Tech: SRAM I-Motion 3 Speed Internal Gear Setup
We love building custom bikes, but each custom comes with a learning curve. This Quiver cafe build is outfitted with SRAM's I-motion 3 internal hub. This hub is a terrific option to add a few gears to your build. It's affordable and simple to use. The kit includes SRAM's 3-speed twist shifter, hub, cable and cable housing. Setup is pretty straight forward, but we'll break it down for you here.
Available for purchase here:
Gearing: 3-speed, 186% range
Hub Versions: Freewheel or Coaster Brake available
Hub Spacing (OLD): 130 mm
Axle: M10 x 1.0
Dropout Width(min / max): 4mm / 8mm
Spoke count: 28 / 32 / 36
Technical data via SRAM Install Manual
Step 1: Build your wheel
We chose the 36 hole version of the hub and laced it 3-cross for a very strong rear wheel that will handle loaded panniers and city streets nicely.
Step 2: Assemble the bits
The hub comes without the dust cover, sprocket and cable stop bracket installed.
- Slide the dust cover onto the hub with the curved portion facing outward.
- Slide the sprocket onto the driver so that the splines engage the driver fully. The sprocket can be assembled with the curved portion inward or outward. Choose the orientation that best matches the chainline of your bicycle. The more common installation is with the curved section inward.
- Install the snap ring making sure the ring is fully engaged into the groove.
- Slide on the cable stop bracket onto the axle. If you have the coaster brake version, orient the cable stop bracket so that it is facing the same direction as the coaster brake arm on the non-drive side of the hub.
- Slide the washer with rubber insert over the axle to secure the cable stop.
Step 3: Assemble the wheel to the bike
- Slide your wheel into your dropout and attach your chain.
- Install the axle washer with the serrations pointed inward towards your frame
- Orient the cable stop bracket so that it is parallel with the chain stay.
- Tension your chain, install the axle nuts and tighten the to 266-350 in-lb (30 - 40 Nm)
Step 4: Install the shifter
- Slide the shifter on to the handlbar until it is flush with your brake lever.
- Tighten using a 2.5 mm hex wrench to tighten the pinch bolt. SRAM recommends a torque of 15 in-lbs (1.7Nm)
Step 5: Install the cable to the bike
Depending on your frame there are a few ways to do this. The key is to make sure the cable housing is attached securely to the frame. You can use your cable guides if they are in a position that accommodates the cable routing needed. The hub comes with enough cable and housing to run a fully housed cable from the shifter to the hub. This is installation we chose. We secured the housing to the frame using a combination of cable clamps and zip-tie clamps.
Step 6: Cut the cable and housing to length
- Position your housing such that you have a gentle bend at the handlebar and insure you have enough of a housing loop such that the handlebars can rotate freely from one extreme to the other. The housing should not be pulled tight throughout the bars range of motion.
- Align the cable to cable stop on the rear hub and mark the housing to cut it to the proper length.
- IMPORTANT: The cable, housing and cable clamp are pre-installed. In order to cut the housing to the proper length you'll need to remove the cable clamp. The distance between the cable housing end and the cable clamp is important so measure the distance which was pre-set by SRAM before proceeding. Ours was set to 20mm.
- Remove the cable clamp and slide the cable housing far enough along the cable so as not to shorten the cable when you make your cut. Cut the cable housing at your mark.Clean the cut end and slide the housing back into its operational position.
Step 7: Install the cable clamp
- Make sure your shifter is in position 1 and there is no slack in the cable or housing.
- Attach the cable clamp at a distance of 20mm from the cable end.
- IMPORTANT: Orient the cable clamp so that the nut is facing outward and the clamp is parallel to the sprocket. This orientation creates the most clearance between the sprocket and the cable clamp.
- Tighten the cable clamp. We tighten it snug to start, once the system is fully adjusted we tighten to the recommended torque.
- Hook the cable clamp onto the actuation cable on the hub. There is a slot on the cable clamp that fits over the outermost barrel end of the actuation cable.
- Pull the cable taught and slide the plastic retainer on to the cable stop bracket.
Step 8: Adjust
Attempt to shift the hub using the twist shifter, You should smoothly shift between the gears with a smooth transition between gears. Adjustments can be made to cable tension using the barrel adjuster on the twist shifter, Rotate the adjuster toutward to tension the cable and inward to loosen tension.
Step 9: Check your work
Take a minute after any install to check every bolt for the correct torque and insure cable housing is secure and free from moving parts.
Written by: Nick Ginster Google
My ride!!! I hope it wasn’t too much of a headache. Did the SRAM present a unique challenge over other internal hubs from other companies or are these instructions there to help people make this same (totally awesome) build?
3 gears is really all you need in Brooklyn and I imagine other cities. Here’s why I think it works perfectly for NYC riding (even after frequently hearing the refrain that NYC is flat and therefore you don’t need any gears:
The easiest gear comes in handy at traffic lights – more so than on hills unless you live in, say, SF. One advantage bikes have over cars is the acceleration off the line. Having an easy gear allows this and when it’s internal you can shift while standing still at the red light that quickly stopped you.
The middle gear is for cruising and for fast uphill riding.
The hardest gear for speed on flats and downhill.
On downhills usually I do max out. I’m looking forward to seeing how it will be with this hub and a different size crank compared to my old ride that had a Shimano nexus and smaller crank.
And having everything contained in the hub, it doesn’t matter if I ride to work in the snow and home on the salt covered streets. Shifting stays constant, secure and weatherproof.
Thanks for building the wheel and the whole bike, Nick and team. I cannot wait to ride it.
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