Rockshox SID Damping Fluid Leak

Rebound rod and seal head close-up

On a ride recently, my forks starting to feel harsh and when I stopped to take a look it was obvious from the dirt on my stanchions that I wasn't getting full travel from the fork.

Pushing on the forks and landing off jumps I could feel a very abrupt end to the travel. The only thing that can cause this is damping fluid migrating from the motion control cartridge/rebound assembly down into the fork lowers. Once down there, its going no-where and the fact that its uncompressable means that you can't get full travel from the fork.

This problem requires a complete tear down of the fork to get at the leaking o-ring seal.

Follow the SRAM manual on disassembly.

There are two o-rings responsible for sealing the damping fluid in the leg. The large one is 24 x 2.5mm and the small is 12 x 3.5mm. It is unlikely that the large o-ring would leak as it does not move. The inner o-ring is likely the culprit as the rebound shaft moves through it so it will wear over time.

Here's a pic of the inner o-ring (the usual culprit) partially removed from the rebound damper seal head:

Rebound damper seal head

Also applies to:

This fix will also apply to other Rockshox forks that use the motion control or blackbox damping system including Reba and Revelation forks.

Related articles:

Rockshox SID 15mm lowers

15mm maxle lite lowers

Rockshox SID Bushing Replacement

Rockshox genuine tools are expensive and hard to find. The bushings themselves are fairly cheap.

Rockshox SID problem diagnosis

Note: these diagnostic procedures will apply to pretty much any Rockshox dual air fork including Reba, Reba 29er and Revelation forks.

Rockshox SID Race 2001

Have just done a complete service of a SID XC 2001 that I got for my next kids bike project. I don't think this thing has ever had a service. The damper oil looked like this:

Rockshox SID Race 2009

What does it weigh?

Rockshox SID Race 2007

Fork with 215mm steerer, starnut installed and v-brake bosses weighs 1318g.