Answer: You got it Nelson. Before you dive in though make sure your frame’s derailleur hanger is straight so that you have a good foundation to build on. I’m going to start from scratch on this tune so that you can understand the entire process and what each adjustment does.
Start with your front derailleur shifted into the big ring. Now move to your rear derailleur and remove the cable from the cable anchor so we can properly set the high limit adjustment. Turning the high limit screw clockwise moves the derailleur inboard and turning it counter-clockwise moves it outboard. Turn the high limit screw until the upper pulley is lined up vertically with the smallest cog on the cassette. Pedal the bike in this gear to check your work while watching and listening for indications that the chain isn’t meshing up smoothly with the small cog.
Now, make sure that you are shifted into the smallest cog and that the barrel adjuster on the derailleur and frame—if there are any on your frame–are turned nearly all the way in. Anchor your cable by pulling it tight with your hand–but not too tight–and then tightening down the bolt that clamps the cable.
Now we’ll adjust the indexing. Make 3 downshifts and then check to see if the upper pulley is lined up with the 4th cog. Use your barrel adjuster to fine-tune the position of the derailleur by adjusting the cable tension. Turning the barrel adjuster in will move the derailleur outboard while backing it out will move the derailleur inboard. Perform some test shifts in the stand to see if your cable tension adjustment is generating smooth shifting. If the derailleur hesitates to shift to a larger cog, back out the barrel adjuster a quarter turn and vice versa if it hesitates when shifting into a smaller cog.
Once you have good shifting and the bike pedals smoothly, it is time to adjust the low limit screw. Shift the front derailleur into the small chainring and then shift the rear derailleur into the largest cog. Be careful to make that last shift gingerly, just in case the low limit screw is so far out of whack that the chain shifts into the spokes. If the derailleur won’t shift into the lowest gear, back out the low limit screw to allow the derailleur to move further inboard. If you shifted into the large cog just fine, then tighten down the low limit screw until you feel it barely bottom out. Do a few test shifts into and out of the large cog to make sure that your adjustment is good.
While you are still in the large cog and small chainring you can set your b-tension adjustment. Tightening the screw down will move the upper pulley away from the large cog while backing it out will push the upper pulley closer to the cog [double check this because I’m not sure if I got that last part backwards]. Campagnolo recommends having a 5-7mm gap between the upper pulley and the large cog. I prefer the smaller end of the adjustment range because it produces faster shifts while extending the life of your drivetrain.
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