You must be completely confident about using the gears on your mountain bike.
This being the case, understanding how to adjust Shimano gears on a mountain bike is well worth spending some time on.
What Are Shimano Gears?
At the time of writing. Shimano is one of the most popular brands of groupset manufacturers in the cycling industry. What this means is that you will come across plenty of bikes from different manufacturers that use them.
There are several different groupsets offered by this Japanese multi-national manufacturer. You might see the likes of Shimano Claris, Shimano Sora, Shimano Tiagra, Shimano 105, Shimano Ultegra, and Shimano Dura-Ace.
Their gears are operated using something known as Shimano Total Integration (STI) levers. They work through the use of two levers, made up of a larger one that has a smaller lever sitting behind it.
How Do You Know That They Need Adjusting?
How will you know whether you have a problem that needs you to adjust your bike’s gears? There are a few tell-tale signs to look out for in this respect. Maybe the chain keeps falling off or the gear change has become sticky and unresponsive.
Changing the Rear Derailleur
Among the main changes, you can make to the rear derailleur are the upper limit and lower limit settings. You can also change the cable tension and use the B tension screw.
The first step is to shift the derailleur down to the smallest of the cogs. You should adjust the small round knob (barrel adjuster) that you see attached to the cable. Turn it in a clockwise motion, this gives you room for further changes later on.
The high limit is the higher of the screws and it is placed across from the barrel adjuster. You will need to use a screwdriver to turn it. A clockwise motion brings the derailleur inwards while turning it in the opposite direction will move it out.
Unscrew the cable anchor (at the bottom of the derailleur) just a little. This is what keeps the cable in place. You can now tighten the cable by pulling it and then tightening the cable anchor again. At this point, you can begin to shift the derailleur by turning the pedal to get the wheel spinning.
It should shift smoothly. If it doesn’t then you can tighten both the lower limit screw and the barrel adjuster until it doesn’t catch anymore.
You can now go back to the barrel adjuster and move it in a clockwise direction. This affects how smoothly the gears work as you shift upwards, so you want to see the derailleur moving smoothly after you have adjusted it.
The next step is to move the derailleur to just underneath the biggest of the cogs. With your screwdriver, you can turn the lower limit screw. The most common adjustment needed here is to turn it in a clockwise direction until it starts to feel tight. You don’t want to leave it too loose but neither do you want to tighten it as far as it goes.
Finally, the B tension screw is found under the cable and you can use it to alter the angle of the derailleur. You will want to turn it clockwise, which moves the derailleur down, while counterclockwise movement brings it upwards. You want to end up with the derailleur close to the cassette but not hitting the cog.
Changing the Front Derailleur
This is the mechanism that moves the chain from one ring to another. The first thing you might want to check here is the height. If the derailleur cage is too high or too low you can change it. There are different bike models, though, so it is worth starting by checking the instructions for your bike. The front derailleur angle of rotation is next on the list. Again, the approach needed here will vary by model.
The limit screws on the front derailleur are usually marked “L” and “H”. You can test both of them, to be sure that they are correctly set up. The “L” screw controls how the derailleur moves towards the smallest of the rings, while the “H” stops the movement towards the biggest of the rings.
This is a job that you can carry out at home and get a lot of satisfaction from. However, if you are in doubt then check with a qualified bike technician before riding it.