Tag Archives: Adjust Derailleur

See how to get the most out of 100 years of technological advancements. You will find adjusting your front derailleur is easy if you follow these steps.

How to adjust your front derailleur for perfect and silent shifting

by John Brown, HaveFunBiking.com

In the late 1920’s, in France, there was a bike race under way and it wasn’t the Tour De France. Instead, this race was a technological race that brought the derailleur into the light. Before 1928, bicycles had a maximum of two speeds, and you needed to remove the rear wheel to change those gears. As there was need for quicker shifting, the bicycle derailleur was born. Initial derailleurs consisted of nothing more than paddles that were actuated by steel rods located between the rider’s legs. Needless to say, there was a lot of finesse that went into shifting those bikes. Then after the second world war parallelogram derailleurs, what we use today, were developed so riders could shift their gears with ease. Read on to see how to get the most out of 100 years of technological advancements. You will find adjusting your front derailleur is easy if you follow these steps.

Front Derailleur

Early “Rod Style” Benelux front derailleur – Yikes

Front Derailleur parts

Limit screws (A) – The front derailleur needs to work within the largest and smallest ring. Limit screws work to stop the front derailleur from shifting outside of its intended range. They are adjustable as to match different types of cranks.

Derailleur Cage – The cage is what holds the chain on gear and what presses on the chain to move it from one gear to the next. The outer portion of the cage (C) is what helps the chain move from larger gears to smaller ones. In contrast, the inner portion of the cage (B) forces the chain from smaller gears to larger ones.

front derailleur

Common parallelogram front derailleur found on Hybrid and Mountainbikes

Derailleur Fixing Bolt (D) – The bolt that holds the derailleur in place on the frame. By loosening this bolt, you can re-position the derailleur for angle and height.

Cable Pinch Bolt (E) – The Cable that controls shifting needs to be held firmly in place. The pinch bolt does that job.

front derailleur

Different Pinch bolt and fixing bolt position for MTB/Hybrid (above) and Road (below) derailleurs

Location, location, location

You guessed it, the most important part of adjusting the front derailleur is its location. If the derailleur is not positioned properly, you will never achieve proper, noise free, shifting in all gears. The reason location is so important is that the front derailleur cage is formed to position the chain in very specific locations.

First step in adjusting the front derailleurs location is to set its height. You need enough room to fit a Nickel between the teeth on the largest chainring and the bottom of the outer cage when they are lined up. Any more clearance than that and the derailleur tends to have issues pulling the chain down from larger gears.

front derailleur

you should be able to fit a Nickle between the derailleur cage and chainring

Once you have the height set, adjust the angle of the front derailleur so that the outer cage and chainrings are parallel. Any misalignment will result in poor shifting and excess noise.

front derailleur

Proper alignment on the left, and misalignment on the right

Lower Limit

Set the lower limit by adjusting the screw marked “L”. To do this, shift the rear derailleur all the way up into the largest cog. Next check to see if there is clearance between the chain and the front derailleurs inner cage with the chain on the smallest chainring. If the chain is running on the inner cage, thread the limit screw out until you have 2-3mm (that nickel distance again!) between the chain and inner cage. When the opposite is true and you have too much clearance between the inner cage and chain, thread the limit screw in until there is 2-3mm of clearance.

Cable tension

Your Front derailleur should be properly aligned and the lower limit should be set at this point. The next step is to attach the cable to the Pinch bolt. Attach that cable by first making sure your shifter is in its lowest gear, Then pull the cable tight, and finally tighten the pinch bolt onto your cable. Usually, you can shift smoothly up from the smallest ring into the next gear right away, but if there is hesitation going up add cable tension either through a barrel adjuster or by loosening the pinch bolt, pulling the cable tighter, and tightening the pinch bolt down again. If the chain wants to shift up from the small ring over the next ring, release some tension. You know you have it right when the chain can pass from one gear to another smoothly and confidently without any banging or skipping noises.

Upper Limit

Setting the upper limit is as easy as getting the chain onto the largest chainring and threading the limit screw to offer 2-3mm of clearance between the chain and the outer cage. While shifting, ensure the chain cannot be shifted over the large ring and off the crank.

Trouble shooting

This guide is great if all the parts are new, but won’t overcome many issues related to worn or dirty parts. The most common shifting issue with older gears is poor upshifting. Chainrings are built with ramps on the inner surface to easily guide the chain from smaller to larger rings. As chainrings wear, these ramps wear as well. If you are having serious issues going from smaller to larger gears, but the gears are silent and problem free otherwise, you may want to consider replacing the chain, chainrings, and gears in the rear.

front derailleur

These Praxis Works chain rings have some of the best shifting thanks to carefully placed ramps.

Another key wear item is the front derailleur itself. Derailleurs are designed to pivot off a parallelogram design that requires each pivot run smooth and precisely. As the Front Derailleur wears, these pivots can begin to bind, while they generate play, leading to poor shifting.

Finally, dirty or corroded cables are a key cause in poor shifting. Replace cables once a year and lube them intermittently to keep them running smooth and freely.

When is enough, enough

Working on your bike is fun, but can be frustrating if things aren’t going according to plan. When things get out of hand, don’t be afraid to start from scratch and go back to step one. Any missed initial steps will make further steps impossible to complete. Also, remember that if it gets too tough, your local bike shop is happy to walk you through the process. You will pay a fee, but the one on one instruction is well worth it.


Tips and Tricks to Adjust Your Bike’s Rear Derailleur

by John Brown, HaveFunBiking.com

It goes by many names, the rear derailleur. It is also known as the “s,” the “hangdown,” or the mech. Here in the U.S. we refer to it as the rear derailleur. The device that moves your bike’s chain from gear to gear letting you traverse hills with ease. Even though derailleurs are sturdy and relatively maintenance free, they do require attention occasionally. Look below for the step by step instructions on how to adjust your bike’s rear derailleur.

 Rear Derailleur Terminology

Twist shifter – A shifting device that rotates around the handlebar like the throttle of a motorcycle.

Trigger shifter – A Shifter that activates by pushing or pulling a set of paddles with your thumb and index finger.

STI shifters – Technical this stands for Shimano Total Integration and speaks directly about one brands type of road bike shifter, but it has become the generic term for any drop bar shifter/brake lever combo.

Thumb shifter – A shifter that can be mounted in many places like; the stem, bar end, brake lever, or top of the bar. These shifters are the most rudimentary type of shifter, and operate by simply actuating a lever with your thumb.

Derailleur parts

(A) Jockey Wheels- two small wheels on the derailleur on which the chain run. They are mounted onto the derailleur cage

Limit screws- The limit screws control the area of motion a derailleur has. On most derailleurs there are three limit screws: the upper limit, Lower limit, and B-limit. The upper limit screw sets the maximum distance the derailleur can shift in high gears. The lower limit screw sets the maximum distance the derailleur can shift in the lower gears. The B-limit screw sets the distance the upper jockey wheel sits from the cogs.

(B) Barrell adjuster – This is an adjustment device on the back of most derailleurs. It is the area where the derailleur cable enters the derailleur and can increase or decrease the cable tension by threading it in and out.

(C) Pinch bolt – The pinch bolt is where the derailleur cable gest secured.

(F) Derailleur hanger – The portion of the bike frame where the rear derailleur is mounted.

Rear Derailleur

Not defined above is the Upper Knuckle (E), and lower knuckle (D)

Is everything straight?

The cogs your rear derailleur shifts across can have as little as 2.14 millemeters of spacing between them. Considering the spacing is so narrow, look to see that everything is aligned properly before you start adjusting your rear derailleur in vain. Look first at the derailleur itself from behind. You should be able to see if the derailleur itself is aligned properly. A tell-tale sign of damage is when the two Jockey wheels don’t line up with the cogs or each other (see picture).

Next assure that the derailleur hanger is aligned properly. This is easily seen when the derailleur appears straight, but not in line with the cogs. Consequently, if either the derailleur or derailleur hanger are bent, it’s best to take it into your local shop for a remedy.

Step 2, A man has got to know his limitations

Before attempting to adjust the derailleur properly, set its usable range. First, loosen the pinch bolt and let the derailleur run on the smallest cog. Next, pedal forward while visually and audibly inspecting how the chain runs on the smallest cog. The chain should run smoothly without any clicking, or skipping noises. If it runs smoothly, don’t worry about the upper limit. when you do experience skipping or noise, look closely at how the chain runs on the cog (looking from behind is easiest). If the chain isn’t coming directly off the upper jockey wheel and going straight onto the small cog you need to adjust the upper limit. By threading the limit in or out you can adjust where the derailleur sits in relation to that smallest cog (note: the limit screws don’t need to get “tightened” down, they simply act as a stop for the derailleur).

Once the upper limit is set, pedal forward and push on the derailleur lower knuckle until it moves the chain into the largest cog. If the chain has issue getting into the largest cog, or jumps over that cog into the wheel spokes, you need to adjust the lower limit screw in a similar fashion to the upper limit screw.

Rear Derailleur Tension

With the limits set, you can now move on to tightening the cable and trying to shift. Make sure the shifter is in its lowest gear by shifting down while gently pulling on the shift cable. With the shifter in its lowest position, ensure all housing ends are settled into the frame properly then pull the cable taught through the derailleur.  With the cable taught, tighten the derailleur pinch bolt onto the cable. Trim any excess cable so that only about one inch of cable extends beyond the pinch bolt and crimp it off as not to fray.

While pedaling, shift one gear up. Ideally, the chain will easily move from the smallest cog up to the next cog. It should stay on the second cog and run quietly and smoothly. If it hesitates to get to the second cog, increase cable tension by rotating the barrel adjuster out. If you cannot increase tension enough with 3 or 4 turns of the barrel adjuster, thread it back in, loosen the cable pinch bolt, pull the cable taught, and tighten the pinch bolt again. Once you have the chain shifting up the cogs easily, check to see if it will smoothly move back down the cog stack by shifting from the largest cog down and inspecting. The only difference is in the adjustment. If the chain hesitates to move down the gears, turn the barrel adjuster in (relieving cable tension).

Rear Derailleur Trouble shooting

What happens if you can get the chain to move up the cogset well, but can’t get it to move back down the cogset easily. In some cases, the cable and housing can be corroded and causing drag. This drag won’t affect the shifting moving up the gear set, but it will stop the derailleur from returning. In tis case, you can clean and lube the cables and housing, or just replace the cable and housing all together.

Additionally, there may be a grinding/banging noise in only the largest cog. That noise is caused by the upper jockey wheel running on the largest cog. To remedy this, tighten the b-limit screw until the noise subsides.

Finally, a common problem is if you get skipping while pedaling up steep grades or under load. If your derailleur is adjusted properly, and you’re getting skipping, it may be related to a worn out drivetrain. As your chain ages, it stretches slightly. As the chain stretches, the front face of the gears will wear in unison with the chain stretching. Once the chain stretches beyond the point where it will mesh with the gears, you will experience skipping under load.

Working on your own bike is fun. Also, your appreciation for the technology and engineering that goes into what is considered a simple machine will grow with each turn of the wrench. Periodically, you will run into a problem you cannot solve. If that is the case, bring your bike to your local shop, talk honestly with the mechanic about what you tried and what you are trying to accomplish. As a result, you will find that most mechanics will be happy to teach you what you need to know.