Which Parts to Replace

How should I determine which parts need to be replaced?

First check all the parts in the diagrams below to make sure that all of the parts listed in red are still good. If any of them are not useable, we do not recommend a rebuild.

Madrone offers the parts listed in green, and they can be selected here. Make sure to check the compatibility on each product page.

SRAM AXS Derailleurs:

SRAM Cable Actuated Derailleurs:

What are the most commonly replaced components?

Very Common / Most Critical

Links and Super Shims

2 common sources of poor shifting are play and deformation in the links and mounting bolt of the derailleur. These are common due to the high stresses in those areas. The derailleur assembly is like complex lever arm where the highest stresses occur nearest to the attachment point.

We find that most used or semi-functional (but not destroyed) derailleurs are brought back to full shifting performance with the Missing Links and Super Shims. These products tighten up the pivots and result in a stiff, well aligned, smooth working mechanism.
Medium Importance

Cages
A bent cage can also contribute to shifting issues, even though the links are more important to address. If your cage is even slightly bent, it will need to be replaced. 

Pulleys
Worn pulley bearings and teeth can be a small contributor to shifting issues. For the upper pulley, shift performance relies upon the bearing tolerances to shift well, and they can wear out quickly when exposed to grit and water. New pulleys can be thought of as putting the “finishing touches” on shift performance to get it back to 100%. 
Not Common

Pivot Pins
Unless the pivot pins of the links are clearly bent, they rarely need to be replaced. However, if you do need them, the Madrone pins are an excellent replacement. Plus, the Madrone AXS pins give the derailleur improved looks!

 

When is a derailleur not worth rebuilding?

There are no good replacement sources for the parts listed in this section. If there are issues with these parts, we do not recommend rebuilding the derailleur unless you have another one that can be used as a unit for donor parts.

Mounting Brackets
If the aluminum mounting brackets (on AXS - the 2 parts that surround the servo) are bent or damaged beyond repair, it is nearly impossible to salvage them. There is no straightforward way to bend them back into alignment, and there are no spare parts. These must be straight and functional for a derailleur rebuild to result in as-new shifting.

SRAM Clutch
The SRAM clutches are not rebuild-able or adjustable. They are manufactured as a closed sub-assembly and molded into a plastic housing. Over time, they lose friction, leading to more chain noise and poor chain retention. If your SRAM clutch is not working, we recommend getting a new derailleur.

Clutch Housing
The plastic SRAM clutch housing should not be deformed or cracked. This is the structural part containing the clutch and torsion spring for the cage. 

On AXS derailleurs, there is also a cosmetic cover on the clutch housing with the SRAM graphics on it. This part has no function, and is not technically required. You may be able to find sources online for them too. More info on the cosmetic plastic covers is here.

AXS Servo

The servos have several components:

  • Battery contacts. These are notorious for having reliability problems. We created a page to help you diagnose and recover them here, and a step-by-step guide to repair them here.
  • Stripped gears. If the derailleur has been forced to move, it can strip the servo gears or cause them to slip and end up incorrectly indexed. This is why you should never force the servo into another gear by hand.
  • Buggy firmware behavior, or damaged electronics. If your firmware has issues, you may want to attempt to get it covered by warranty, but the outcome may be determined case by case.
  • Bent servo lever arm. These can get bent in large impacts.

Battery Latch
If your plastic SRAM battery latch is broken or worn out, unfortunately we do not have a solution for this.