31 Dec How to adjust the rear derailleur on your bike?
Nothing like a few gears running efficiently to make your rides more enjoyable. Although at first glance it seems too complicated, actually adjusting your rear derailleurs is relatively easy. Here we will tell you how to do it. You should adjust rear derailleurs if there is something wrong with them. At first, it might not be apparent as a common practice that we need to change our bikes’ gears. Once you notice some clutch slippage and problems shifting asymmetrically, then you can decide on changing the rear derailleurs release or even your wheel side pull brake cables too.
What is a rear derailleur in the bike?
Rear derailleurs are also commonly known as gears and shifters. Rear derailleurs in bikes can be fitted to use, but you need a special cable for them, which is called a rear derailleur release (RD). You can see the best quality front and rear in the best fat bikes under $500.
This RD comes with two wires. One wire has no purpose. But one of these wires that fit on the frame must have contact directly to each ring gear at the same time. That way, we can transmit force to the rear wheel.
- Small screwdriver
- Allen keys
Rear derailleur adjustments
- Limit screws
- Whip tension
- Vertical tension screw (on some mechanisms)
The rear derailleurs have a pair of screws that serve as physical stops to regulate the operating range of the mechanism. They are usually marked one with an H (High) for the smallest sprocket limit and L (Low) for the largest. Adjusting these stops ensures that the chain does not move past the end sprockets.
The position of the derailleur is controlled by the tension of the whip that connects the controls to the mechanism. The vast majority of the mechanisms are “Normal High,” and as they do not have tension, they pull the chain towards the smallest sprocket, that is, towards a high speed. It is possible to find mechanisms that push towards the largest pinion by not having tension on the whip (Normal Low). Having adequate tension ensures that the derailleur selects the desired sprocket, that is, that it is well-indexed.
Vertical tension screw
This screw regulates the vertical distance between the pinions and the guide pulley. The idea is to keep the idler as close to the sprockets and to shift more efficiently. It is important to note that not all mechanisms have this setting.
How to adjust your rear derailleurs?
In order to make the adjustments properly, it is recommended to position the bicycle in such a way that the rear wheel is in the air and can rotate freely when pressing the pedals. Additionally, you should be able to control the controls while pushing the pedals. Ideally, you should mount the bike on a workshop stand, but it is not necessary.
The procedure that we share below is to adjust “Normal High” mechanical derailleurs since these are the most common and it is similar for mountain and road bikes.
Before starting, it is important to check that your mechanism (pulleys and cage) are perfectly parallel to the pinions. If not, it is very likely that the leg (Hanger) is bent and it is necessary to straighten or change it.
Adjust the H and L limits
- Release the whip – Using the controls, select the smallest pinion, and with the Allen key release the whip.
- Adjust bolt H – When driving the wheel with the pedals, the derailleur will tend to move the chain towards the small sprocket. Tighten or loosen the limit screw H so that the chain stays at the highest speed (smallest sprocket) without making noise and without coming off. Make 1/2 turn adjustments for more precision.
- Adjust the L stop – Screw in the L stop fully and push the mechanism by hand (remember that the whip is not attached) towards higher speeds while turning the pedals. With the screw all the way in, you will most likely only get to the second or third sprocket.
- Unscrew the stopper L little by little – While driving the wheel with the pedals, turn the screw 1/2 turn at a time until the derailleur moves the chain to the largest sprocket. Once the idler pulley is perfectly aligned with the pinion, the lowest speed stop is adjusted.
- Extract the maximum length of the whip – Place the knob in the position corresponding to the smallest sprocket and pull the end of the whip.
The tensioner (barrel screw) is used to give a fine adjustment to the tension of the whip. Screw-in the tensioner as far as it will go, and then turn it two turns in the opposite direction so that you have room to play with the tension.
- Attach the whip to the mechanism – Place the whip, ensuring that it is in the correct position and tighten the screw. Don’t over-tighten, as you could damage the whip.
- Test the tension setting – Using the knobs, try to shift to the next sprocket. You will probably notice that the chain makes a bit of noise, cannot make the change, or skips more than one sprocket.
Tighten or loosen the tensioner as needed so the derailleur makes a single shift with each click of the knob. If it shifts correctly but makes too much noise, give a slight adjustment with the tensioner to align the idler pulley with the pinion. To ensure accurate adjustment, it is recommended to turn the barrel screw ½ turn at a time.
If the chain is trying to change more than one sprocket at a time, you will need to release some tension.
If it is difficult to change to the next sprocket, you will need to give more tension to the whip.
- Adjust the vertical distance – With the controls, select the lowest speed (largest pinion with the smallest chainring) and adjust the vertical tension screw.
When screwing, the mechanism moves away from the pinions and when unscrewing, it is closer.
The ideal is to leave it as close as possible, without making noise, about 5 mm more or less, depending on the characteristics of the mechanism you have.
As you can see, alignment and tension are essential for your changes to work well. If you can’t adjust your gears correctly by following the steps above, make sure that the derailleur leg is not bent and that the whip and lining are clean.