Sunday, October 20, 2013

Preparing the Shifters for Antarctica

I have Shimano SLX shifters I will be using on my expedition bike. Shifters have a little bit of grease in them that keeps them working smoothly. However at the extreme colds of Antarctica the grease can get very viscous which could make the shifters not work. So I will be replacing the grease in the shifters with Lubriplate mag 1 grease. 

While I am doing this I might as well remove the gear indicator. I guess it is just some kind of bike snob thing, but serious bikers do not have indicators that tell you what gear you are in. If the pedal speed is comfortable then you are in the right gear. Removing the indicator save a little weight, but in the whole scheme of things really doesn't matter. Anyway first step is to undo the two screws that hold the indicator on.
The shifters come with a cover that can be put in place instead of the gear shifter. And now we have a nice clean looking shifter that is free of the gear indicator.
 To remove the grease I need to open up the shifter. This is easily done by removing one screw on the cover as seen in this picture.
 Here you can see some of the grease. The real problem is the grease on the pawls that can't be seen in this pictures. I fix old shifters in my bike shop all the time that old grease that is all gummed up. The pawls are spring loaded and provide the ratcheting for changing gears. When the grease gets too sticky then the springs don't have enough force to push the pawls against the teeth of the ratchet. Cleaning the grease from the pawls fixes the gears. I don't want to have to do this on the polar plateau.

First I spray in a generous amount of degreaser to loosen up the grease. Then I rinsed the shifters in water. I don't want the water corroding things so I spray some alcohol in the the shifter, and then blow in dry with my compressor.
After all this you can see that my shifter is free of all the grease. The shifters work just fine without the grease and I could just use them grease free like this. However the winds of Antarctica blow around tiny ice crystals that can get into everything. To protect the shifters from getting iced I will add the Lubripate mag 1 grease that stays good at the -40º temperatures that I will be biking in.

While I am working with the shifters I also change the switch on the shifter to make it work with a double crank.

And now my shifters are ready to go to Antarctica.

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