Enviolo Rear Cog Replacement

The rear hub uses a “freehub” system to mount the singlespeed cog. The sprocket is a 9-splined Shimano HG-compatible BMX style that uses a 3/32” chain (derailleur chain). 

Begin by shifting the cable attachment point on the Hub Interface fully counterclockwise or fully clockwise. If it stops turning before full rotation, hold the axle and spin the wheel a bit, then continue. Note the position of the Hub Interface, relative to the flat sides of the axle.I like to make a sharpie mark on the hub shell for each corner of the Hub Interface to make it easier to mount in the same position. From here forward, do not rotate the axle or cable anchor on the Hub Interface. 

Remove the hub interface. Remove the axle locknut (17 mm, not shown below) and then lift the Hub Interface. Some hubs have a washer between the locknut and the Hub Interface; some do not.


Remove Hub Interface.


Lift the hub interface using a wider flat-bladed screwdriver under the unit, gently prying it upward (figure 44).

The sprocket is held by a snap ring. Use a small screwdriver to lift off the snap ring and remove the cog.


Place the new cog on the freehub and replace the snapring. 

With the cable anchor of the Hub Interface still at its fully rotated position, line up the Hub Interface with your marks from earlier and place it on the hub. You may have to make small adjustments to get the splines to line up, this is not an issue. 

Install washer if present and 17mm nut. Tighten the nut just a little more than hand tight - it doesn't need much. 

Reinstall wheel. 

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