My Bicycle STI shifting is changing.?

B

Bob A

New member
This is typical of a new bike the cables stretch a little and change the shifting. There is a barrel adjuster right where the cable enters the rear derailleur. It will have little nubs on it. Usually you have to turn it out, counter-clock wise to take care of the cable stretch. Try 1/2 turn at a time and then ride your bike. If you down shift and it doesn't shift to the next gear try another 1/2 turn. When you get it close make smaller adjustments. I like to use a cable lube like Tri Flow and also put a little on the derailleur pivot points.

The bike shop will normally do this adjustment for free but it's good to know how to do it. You can watch this video but don't touch the screws, they never need adjusting once they are set up.

http://bicycletutor.com/adjust-rear-derailleur/
 
My new bike came with STI shifting. I never had it before. When It was new it shifted with one click of the lever. Now (after 600 miles or so) it often takes two clicks to shift up or down one gear. Do I need to adjust the cables, or is this normal? (Shimano 105 shifters and derailers).
 
You have 2 good answers already, but I would like to add.

If you have water bottles that you normally fill with sports drinks, check your cable guides under the bottom bracket. Leaking, splashed or dripped dried sports drink can turn into a goo that will interfere with the precision of your shifting. Clean the cables and guides after turning your bike upside down. Scrub with plain hot water with an old tooth brush. Take a finger full of common grease and pack the guide cable track. It will be well lubricated for the cycling season and no more drips can cause sticky cables. Clean and replace the grease annually.
 
It's very typical that cables stretch a bit on a new bike after a couple of hundred miles. Take the bike back to where you bought it. Every time I bought a new bike the shop did this "break-in" adjustment for free. They should do the same for you, too.

HTH
 
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