How to: Modify Shimano Left Shifters For Use as Dropper Post Switches

A large percentage of riders with dropper posts are also running 1x10 or 1x11 drivetrains. That means that there are thousands of front shifters lying around doing nothing, and there is an empty spot on the handlebar next to the left brake lever on each of these 1x bikes. With these video you'll learn how to take that useless old front Shimano shifter in your parts bin and turn it into an awesome dropper post switch for free!

Of course this will void your shifter's warranty, so after you make this mod, do us a favor and don't try to warranty it when you either do it wrong or decide you don't want it anymore!

Before you dive in, make sure that your dropper post will work with this type of switch. You need a post that is made to have the cable head installed in the switch, rather than in the post. Examples of compatible posts are the Kind Shock LEV and the 2nd generation Kind Shock LEV Integra with this style of cable attachment assembly at the bottom, and all versions of the Specialized Command Post.

Here’s a Shimano Saint M810 shifter that we’ve already modified. We’ve removed the pawl responsible for preventing cable that has been reeled into the shifter from being let out again without pressing the cable release button on the shifter. Whichever model of Shimano shifter that you are modifying, you need to locate and remove the pawl responsible for this process. In the case of this Saint shifter it required grinding off the head of the rivet holding the pawl in, but your shifter may be different.

Take this Shimano XT M780 front shifter for example. With this shifter you’ll need to first remove the gear indicator or upper shifter cover along with the cable port plug and barrel adjuster. Then remove the screws on the underside of the shifter. For a non I-spec version like this one, we have to remove the handlebar clamp as well before the shifter’s upper cover can be removed. Now remove the plastic plate that guides the gear indicator. Even if your shifter did not come with a gear indicator installed, this part will be inside the shifter. We now have access to the shifter’s internals.

The pawl that needs to be eliminated is right here. It is held in place by a clip that can be removed with a modified flathead screwdriver. Be careful not to lose this clip as you are removing it. Pry up the upper steel plate on the shifter mechanism and then use a pick tool to push the spring and pawl up and off of their pivot. Keep in mind that the barrel adjuster is held by this plate and can fall out while prying the plate up. If that happens, don’t worry, it’s easy to reinstall.

Reinstall the clip on the pawl pivot post with a pair of pliers. Now you can check to make sure that the shifter functions without getting hung up at any point in the lever sweep.

Now we can remove the cable release lever. This isn’t necessary, but it makes the switch look a little more finished while making it a little lighter. You can wait to do this until after you have finished reassembly to prevent metal filings from getting in the shifter, but it’s a little easier to do a clean cut on the lever without the shifter fully reassembled.

Clamp the cable release switch lever into a vice and use a hacksaw or Dremel cutoff wheel to sever the lever. Then clean up the cut edge and make it flush with the shifter body. If you want to go the extra mile you can use a sharpie to make the missing switch just a little more invisible.

Now we can finish the reassembly. Reinstall the plastic gear indicator plate. Then install the upper shifter cover and the screws that hold it in place except for the screw that interfaces with the handlebar clamp or i-spec assembly. Now install the handlebar clamp followed by the final screw on the underside of the shifter. Then install the barrel adjuster and the secondary shifter cover or gear indicator. Double check the switch’s function, mount it up to your dropper post and enjoy your new, free custom-made dropper post switch!