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Convert Shimano Ultegra 6870 rear mech from short cage to medium cage

6 min read

Asked by: Lee Ferguson

Can you make a short cage derailleur into a long cage?

Yes, if the derailleurs are the same model, and you can get all the parts, (which isn’t usually a straightforward process) youcan convert from short cage to long cage. That’s assuming that the rest of the derailleur is constructed the same way, which is not guaranteed.

Can you change rear derailleur cage length?

Generally you can replace a derailleur with a longer caged one without any problems. The length of the cage determines the “spread” of gears that the drivetrain can support. So, for example, the short cage might get you a 11-28 cassette where a medium cage might work up to 11-32.

Are Shimano derailleur cages interchangeable?

Yes. If the derailleur is damaged, the body is physically the same, too, and the cages can be interchanged.

What is the difference between a short medium cage rear derailleur?


Quote from video: And it houses these two jockey wheels on a short caged derailleur like this one the jockey wheels will be quite close together and then a longer cage one they'll be much further apart.

Is short cage better than long cage?

Longer cages accommodate a wider gear range better, giving you a more stable chain line and reduced slack.

Do I need long or medium cage derailleur?

If you are in-between the capacity ranges of the two, which is often the case with mountain bikes, then note the following: long cage derailleurs will accommodate a wider gear range and deliver a better chain line, while medium cage derailleurs are less likely to be hit by rocks on the trail.

Can I replace derailleur cage?

Quote from video: Well there's two reasons I can think of one your derailleur cage might have been bent or twisted in a crash or. Two. You want to actually replace. A short cage with a longer cage.

How do you increase rear derailleur?

If you have a rear derailleur with the short (SS) cage, you can certainly buy a new rear derailleur with the longer, GS cage. And if your current derailleur is non-DM, you can replace it with a DM Di2 RD, and your shifters will send commands to it just fine. You can also switch out the jockey-wheel cage alone.

What does GS mean on Shimano derailleur?

medium cage

Shimano rear derailleurs are available in two types, SS (short cage) and GS (medium cage), depending on the model. The “cage” here refers to the length of the pulley cage (the unit that houses the two pulleys).

Can you mix Shimano groupsets?

It is possible to mix and match as long as you get components from the same generation. For example: 9000 Dura Ace, 6800 Ultegra, and 5800 105 are all cross compatible. Each have 11-speeds in the rear, use the same cable pull per shift and use the same front derailleur design.

How do I identify a Shimano Ultegra rear derailleur?

Shimano stamps the rear derailleur model number on the underside/lower plate of the parallelogram.

How do you change a Shimano rear derailleur?

Quote from video: Put the mech to the smallest sprocket using your sti's. Pull the cable crimp off the end of the inner cable using some pliers then undo the cable crimper bolt by unscrewing it anti-clockwise.

What are the advantages of a short cage derailleur?

logged out. Short cage derailleurs generally have higher spring tension, having a shorter cage means less chainslap too. A closer range cassette, such as a road cassette, means less jump between the gears, so you can accelerate through the gear range smoother than you can with big jumps through the gears.

What is the max cassette for short cage derailleur?

All derailleurs have a maximum cassette size. This is often indicated as the maximum number of teeth that can be on the biggest cog (often referred to as low sprocket max in manuals). So when you see that a derailleur has a maximum cassette size of 30T you know that the biggest cog on the cassette cannot exceed 30T.

How do I know what size derailleur cage to get?

Quote from video: The most simple and straightforward way to think about cage lengths is as follows. The wider range of gears you have the larger the cage you'll need for those unsure about what ranges.

What’s the difference between long cage and short cage derailleur?

A chain that slacks can be represented as the force acting on the lever (derailleur’s cage in our case) and puts tension on the spring. Long cage = easier to move / short cage = harder to move. If you use only one chainring you can use a short cage derailleur.

How do you change a derailleur cage?

Quote from video: It into the bolt. Here with a quick twist. Comes. Right off and then also with the other one quick little loosen bolt comes out and the cage is free now we have this inner plate.

What is the max cassette for short cage derailleur?

All derailleurs have a maximum cassette size. This is often indicated as the maximum number of teeth that can be on the biggest cog (often referred to as low sprocket max in manuals). So when you see that a derailleur has a maximum cassette size of 30T you know that the biggest cog on the cassette cannot exceed 30T.

How do I know what size derailleur cage to get?

Quote from video: The most simple and straightforward way to think about cage lengths is as follows. The wider range of gears you have the larger the cage you'll need for those unsure about what ranges.

How do I identify a Shimano Ultegra rear derailleur?

Shimano stamps the rear derailleur model number on the underside/lower plate of the parallelogram.

Does cage length affect chain length?

Cage length doesn’t impact the chain length, but a longer cage can help with a small-small. Because the longer cage pulls the chain further back the derailleur is less likely to fold on itself in extreme ratio situations.