Shimano makes about 15 different shifters for all types of bikes. Shimano's three STI--Shimano Total Integration--shifters stand out as their flagship models. These are the Dura-Ace, the Ultegra and the 105. Integrated handles are a single handle that operates the brake and shifter. Pull on the handle to brake or push sideways on the handle to shift to lower gears. Push on a smaller lever tucked underneath to shift to higher gears. When the shifter-brake handle is pushed all the way open to one side, it exposes the end of the cables for easy replacement if they break. To change out the entire integrated handle, a 5mm set screw is located underneath the rubber housing at the bottom of the unit. Look for the words, "Flight Deck" inscribed on the chrome top of the handle.
If an STI shifter handle happens to break--which is extremely rare--the handle is impossible to work on. It has to be repaired or replaced by an experienced mechanic. The handle can be hard to shift after eight or nine hours on the bike when hands have cramping or numbness from hours of pressure on the nerves.
Where To Buy
Always buy Shimano shifters at your local bike shop if possible. They have the mechanics to install and adjust them. In addition, they can insure that you choose the right one. The other option is the nearest REI. They too have a superior selection with good prices and mechanics, and have all other accessories to compliment your shifter selection. The most affordable place to buy is online through Bike Nashbar, or Performance Cycling.
Prices can range widely for Shimano shifters. Don't pay more than about $200 a pair for the 105. For the mid-range Ultegra, expect to pay about $300. Top of the line Dura-Ace shifters will cost about $400.
Shimano makes cheaper shifters. The Tiagra and the Sora are two entry-level shifters that are installed on bikes priced under $1,000. The downshift button on these shifters is on top of the handle instead of underneath. This changes the hand position slightly, which may be slightly less efficient.
Whenever shifters are changed, new bar tape should be installed. Buy cork or Roubaix handlebar tape for about $20. These two types of tape come in many colors to match even the wildest bike paint schemes. The cushion provided by these tapes helps prevent numb palms on long rides.
Don't forget to also buy a pair of riding gloves with padded palms for about $20.
Get accustomed to your Shimano STI shifters before hitting the open road. The shifter handle is also your brake handle. Don't make the mistake of pulling back on your shifter to shift instead of pushing it sideways. With the stopping power of modern V-brakes, it could cause your front end to skid, causing you to crash.