CSL DD/DD Pro shaft and stem interface slop solution
I recently bought one of those "flex fix" 3d printed sleeves things from Etsy. Really all they do is snug up against the metal QR to remove some slop on that end.
But we all know the real weakness is at the shaft end.
The small movements over time cause disconnections and then we have to tighten the collar again, and again. I wish there was a way to get that stem against the tightened collar. So here's what I did.
The flex fix thing I bought from AT3DSimShop
I used a 2.5mm bike bottom bracket spacer from my bike parts bin. They're cheap on amazon or a bike shop might just give you one.
Put the spacer inside the sleeve thing
Put the stem through
Put the collar on and tighten slightly just to hold in place. Then put the stem into the shaft. You cant see it but this is where the collar pushes to.
Now here's the trick. You've got to preload the collar, sleeve and stem against each other, like this, while simultaneously pushing the whole thing into the shaft. Having an extra set of hands help with one holding stem assembly and the other person tightening the collar helps. I just did it one handed.
After tightening the collar check for any gaps between it and the black sleeve. Since the sleeve is imperfect just rotate it until there is little or no light between it and the collar. There should be no play in the plastic sleeve if you wiggle it. Then tighten the set screw in the sleeve.
End result is that there should be a lot less chance for that stem to move around if it is tight against the collar.
Now since my unit is out of warranty anyway I replaced the stock collar with a light weight 2 piece collar. I like the amount of contact area there is.
To me it feels a bit better than before but time will tell if I eventually get another disconnect. The goal was to give the collar and stem a stronger interface by backing the entire stem assembly up flush against the collar so pre loading is the key. I think a 3d printed sleeve that is at least as wide OD as the widest part of the stem and as long as needed to properly space the collar on the shaft is ideal. If the piece I bought was just 2 to 2.5mm taller it would have been perfect.