SR Suntour Edge shock stuck down

 The SR Suntour Edge shocks are popping up on a number of bikes these days and they seem like quite a nice little shock.

We have heard of and seen a number on Focus Thron e-bikes that have been "stuck-down"

This is where the main chamber pressure ends up in the negative chamber and causes the shock to collapse on itself.

There are plenty of references out there on how to release a stuck down shock (I generally stick a rag through the eyelet to stop the can flying off)

But the main issue is the cause of the air leak and how to fix it.

With the ones we have seen it is the same cause each time and that is a sharp edge on the transfer port in the air can. As the main seal passes this port it get cuts, and over time this is enough to allow air from the main chamber into the negative.


You can see the transfer port in the image above. If you run your finger over the port you'll be able to feel if there are any sharp edges.


In this you can see the cut on the main seal where in this case the one edge of the port has cut.

If you take a piece of fine (1200 grit is good for this job) wet and dry sand paper and lightly polish around the transfer port, checking regularly until you can feel the edges are no longer sharp. 

Once done clean the air sleeve out to remove any rough stuff. Now replace the main seal (unless you are getting to this well early and no damage done). If you can't get a service kit given the scarcity of parts at the moment, you just need a BS218 quad ring.

Use slick honey or slickoleum on all the moving seals ie the main seal and negative seal in the air can and reassemble.

If you have any additional thoughts or observations on this please feel free to leave a comment.

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