Garage Files: How to Install a OneUp Shark 50-Tooth Conversion

How to Install a OneUp Shark 50-Tooth Conversion

Get More Out of Your Gears

We reviewed the Shark 50-tooth conversion from OneUp in our recent May issue. This affordable conversion received top marks from all of our test riders, and we have continued to put miles on this kit since the review. Not everyone can afford the fancy new 50-tooth drivetrains, but the Shark offers wide-range gearing at a much more realistic price. The conversion is hands-on and requires some finesse, but by following the proper steps outlined here, most riders will be able to do this right in their own garage.

1-To do this conversion, you will have to remove your rear wheel and use a chain breaker to separate your chain. You most likely won’t be able to reuse your existing chain, since the 50-tooth will need more chain links to work properly.

2-Once your wheel is off and the chain is cut, remove your rear derailleur as well. It will be much easier to replace the cage on your workbench.

3-Switch the clutch into the “off” position to make taking apart the spring easier.

4-With the clutch turned off, take a 3-millimeter Allen wrench and take off the outer cage and pulley wheels. Put the pulley wheels in a safe place; you will need them later when we install the Shark Cage.

5-Take a Phillips-head screw-driver and remove the cage-stopper pin. You will have to squeeze the derailleur to move the cage away from the body.

6-7-It’s time to release the cage spring tension. Squeeze the cable guide and bolt knuckle together and rotate the cage counterclockwise 180 degrees. You will feel the cage tension let up and the cage will hang freely.

8-9-Use a 2-mil- limeter Allen wrench to unthread the screws holding down the clutch cover. Keep an eye out for a small seal between the body and cover; you will need this when reinstalling the cover.

10-11-Use your 4-millimeter Allen to unthread the inner cage. You won’t need the stock Shimano cage anymore; put it away somewhere safe for a rainy day. There is a small metal washer on the cage that you will need for the Shark Cage. Remove it for the next step.

12-Take the inner Shark Cage and pin provided by OneUp. Next, grab that metal washer and install it around the pin facing the spring.

13-It’s time to install the spring on the Shark Cage. There are a few different holes on the cage depending on what type of derailleur you have. Install the hooked end in the corresponding slot.

14-Reinstall the spring and new Shark Cage onto the derailleur body. If you look inside the derailleur housing, you will see a slot where the flat end of the spring fits in. Be sure this lines up. It may take a few tries to get it right.

15-Next, take two 4-millimeter Allen wrenches to tighten down the Shark Cage to the clutch body. The Shimano torque spec is 8 N/m.

16-Reinstall the clutch cover using the 2-millimeter Allen wrench. These bolts are small and can be easily stripped, so turn until they are snug.

17-18-We have put preload on the spring tension. Pinch the bolt knuckle and rotate the Shark Cage clockwise 180 degrees. You will feel the tension get tighter as you rotate it.

19-Install the longer cage stop onto the Shark Cage.

20-Take the other side of the Shark Cage and install it with the original pulley wheels using the 3-millimeter Allen wrench. Tighten down each bolt slowly until it is snug.

21-The last steps involve installing the 18- and 50-tooth cog on the designated cassette. Our Shimano M8000 cassette is compatible with the Shark conversion. Take the chain whip and lockring tool to break the lock ring loose.

22-23-Once the cassette is off, take off the stock 17- and 19-tooth cogs and replace them with the OneUp 18-tooth cog. You will have one extra spacer after doing this that you can save with the other cogs.

24-25-Take the 50-tooth Shark cog and install it on the freehub body first. Then, install the rest of the cassette on the 50-tooth cog and tight- en down the lockring to 40 N/m. Use the ground as leverage to get the ring tight enough.

26-Reinstall your rear derailleur and wheel, along with a new chain that is long enough to suit the larger 50-tooth cog. You will have to readjust the derailleur, which might be a bit tricky. If you aren’t comfortable doing this, take it to your local shop. Aside from that, you’re ready to ride.


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