Disclosure: When you buy through our links, we may earn a commission

How to setup and adjust the rear derailleur of your mountain bike

In this article I’m going to describe the steps involved on how to setup and adjust the rear derailleur of your mountain bike. The process is the same for any other bike as well.

I installed XYZ Ultralight handlebars on my Super V. And because I did the grip shifts that came with the bike needed to be changed because they couldn’t go pass the curve of the bars.

So not only did I buy a pair of Deore XT 3×8-speed trigger shifters, but would also need to redo the entire drivetrain setup.

Compatibility issues

The Super V runs the original front- and rear derailleur from 1994, the year the bike was released. And the Deore XT SL-M740 trigger shifters are also from that year. This means that both the shifters and derailleurs are from the same brand and fully compatible with each other.

To be as compatible as possible, and coincidentally be period-correct as well, I reinstalled the Deore XT rear derailleur again.

As it turned out, the Super V had a front derailleur that was incompatible with a triple setup. The chain started to rattle in the derailleur cage which didn’t get low enough.

It was no wonder the front derailleur was not the original one. As soon as I did swap it out for one that came with a Cannondale Super V 1000 from 1994: a Shimano LX FD-M556, the problem was solved.

What I’m trying to say with all this, is that staying as close as possible to the original setup will reduce the risk of running into compatibility issues.

How to adjust your rear derailleur

One of the reasons people don’t like running triple cranksets anymore is because adjusting the rear derailleur to smoothly cover the entire range of both the cassette and chainrings isn’t as easy as it sounds.

Barrel adjusters

Before I start adjusting the rear derailleur, I make the barrel adjuster from the shifter is all the way turned in.

If your rear derailleur also has a barrel adjuster turn it inwards as well.

Both barrel adjuster can then be turned outwards 1 or 2 rotations to give you some room to adjust either way.

Limit screws

I also make sure the limit screws are turned outwards, so the rear derailleur has its widest range possible.

After you’ve installed the cable, you can set the limit screws in such a way that the rear derailleur sits below the smallest cog of the cassette as a starting point. When you rotate the crank and start shifting you learn soon enough whether this initial position is the correct one.

Worn vs new parts

The shifters, cassette, chain and chainrings are all brand new parts. That means I won’t be running into shifting issues related to worn parts.

A cassette doesn’t wear out evenly. It’s a common sight that the middle sprockets are way more worn after extended use, than the outer sprockets, simply because they are used more.

And with significant wear, no matter how wel you try to finetune with barrel adjusters, you will not get your drivetrain to work correctly.

If you get it to work in the lowest ranges, you run into issues with high gears, and vice versa.

Should you decide to chain your cassette, always change your chain as well, or else you’re still running worn parts. Considering the fact that chainrings wear out much slower, you don’t always have to change those.

You might also like