How to Set Up Gears on a Mountain Bike

How to Set Up Gears on a Mountain Bike
Ideally, your mountain bike will be ready to ride straight out of the shop doors, assembled and fine-tuned by professional bike mechanics. However, if you've ordered a bike online or are experiencing issues, you may need to set up your own gears. Here's a walkthrough on what you'll need to do. This information was derived largely from Lennard Zinn's "Zinn and the Art of Mountain Bike Maintenance." Refer to this informative book for a more thorough treatment of this and many other bike maintenance/repair issues (see Resources below).


Difficulty: Easy

Step 1
Take the bike back to the shop. If you've recently purchased your bike at a local bike shop or sports retailer and it is experiencing shifting issues (i.e. sluggish shifts, won't shift to the last gear, overshifts off the gear) take it back to the shop. Any reputable shop should sell an operational bike and they should fix any initial issues for no cost. This is part of their job. If the shop is too far away, or you purchased the bike online or through a retailer without full service, proceed with the next steps.
Step 2
Using a bike stand or hooks, suspend the bike. It will be easier to work with the bike off the ground.
Step 3
Ensure that the front derailleur is attached properly. The derailleur will be attached to the seat tube with a clamp. It should be perfectly parallel with the gears and about 1-2 mm above the largest gear. If it is not, use Allen wrench to loosen the clamp bolt and adjust as needed.
Step 4
Adjust limit screws. Limit screws are 2 small screws side-by-side, ideally labeled "H" for High limit and "L" for Low limit. If they are not labeled, the one closest to the frame should be the Low limit; however, if you turn this screw when derailleur is on low gear and nothing happens, it is the High limit screw (varies by individual derailleur model). See Steps 5 and 6 for specific adjustments.
Step 5
Adjust Low limits. Using left shifter, shift to lowest (smallest) gear. If the chain has shifted too far over the gear and onto the crankshaft (overshift) tighten (righty tighty) the Low limit screw ? turn at a time until chain does not overshift, but stops on lowest gear. If chain undershifts or is difficult to drop into lowest gear, first check to make sure that the cable is not too taught, which would impede derailleur's movement. If cable is taught, turn left barrel adjuster (located on the top of the cable next to the left shifter) clockwise to loosen. If cable is not impeding derailleur's movement, loosen Low limit screw a quarter turn at a time until it drops smoothly into gear.
Step 6
Adjust High limits. Shift front derailleur to the highest (largest) front gear and repeat Steps 4 and 5. This time you'll be using the High limit screw, but directions are the same (tighten screw for overshift and loosen for sluggish or undershift).
Step 7
Check front cable tension. After limit screws are properly set try shifting up and down all front gears. Chain should shift smoothly between each gear. Use the barrel adjuster (located on the top of the cable next to the left shifter) to make adjustments. Turn the adjuster counter-clockwise to tighten a loose cable that may cause problems upshifting to higher gear and turn clockwise to loosen a cable that may cause downshifting problems. If this doesn't work you can also loosen Allen bolt on the front derailleur and pull the cable taught this way.
Step 8
Repeat the process for limit screw adjustments and cable tension for the rear derailleur. Like the front, rear derailleur will have 2 limit screws, ideally marked "H" and "L." The High limit screw should be above the Low limit screw but, again, you may need to double check by trying it because derailleurs differ.
Step 9
Use right shifter to shift to lowest (largest) rear gear. If the derailleur will not shift to lowest gear, use a Low limit screw to adjust undershift (loosen a quarter turn at a time). Adjust accordingly for any overshift (tighten a quarter turn at a time).

Step 10

Step 1
Repeat Step 7 for rear derailleur High adjustments by shifting to the highest (smallest) gear and adjusting cable tension and High limit screw as needed.

Step 11

Step 1
Adjust up and down through all rear gears using right shifter. Shifting should be smooth and stop at each gear. If it does not, use the barrel adjuster located on the rear derailleur or right shifter (depending on bike) to adjust cable tension as needed. Turn counter-clockwise to tighten cable for problems shifting to lower (larger) gears and clockwise for problems shifting to higher (smaller gears).

Article Written By Chris Weiss

Chris Weiss is a freelance writer and outdoor enthusiast living outside of Salt Lake City. He has been mountain biking and snowboarding for over 15 years. Chris has written for various travel and outdoors websites and publications, and hopes to convey his experiences and passion for the outdoors to other enthusiasts and readers.

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