Poblem with Q45- Top steering post clamp slipping?

[DrDave39]

Getting my new Q dialed in. For some reason, the top clamp (the one with 2 5mm bolts on either side, which sets the handlebar height) keeps slipping. All the bolts are plenty tight and I'd feel any more would be overtightening them (I'm a fair bike mechanic).

The left side from the back of the bike) seems fixed and doesn't turn at all. The right is snugged as far as it will go. Is the left side key-slotted, or some other reason it doesn't turn at all? I'm thinking I need to disassemble it and check it out, but thought I'd ask here first.

Dave

 

[DrDave39]

Sorry, somehow this double posted...

 

[benphyr]

I’m not sure which clamp you are referring to. Can you post a picture ? Is it the clamp that would be a stem on a diamond frame bike? If so, is it the stem to fork steerer tube or the one that clamps on the boom slider that you are having difficulty with.

 

[DrDave39]

This is it. You can see it's slipped up a bit from my trailside fix (the white area was completely covered). When it slips, it goes up on the mast, which lowers the bars and lengthens the reach to the pedals.

 

[CoolBreeze]

DrDave39,
One of those bolts is actually an internally threaded tube, and the other a bolt. You need to disassemble the part and then see what is preventing the clamp from exerting enough force to keep the boom from slipping. It may have been mistakenly assembled with too many washers, as one possibility.

 

[Mathew Fy]

I had slipping on my boom when it was new. Retightening after riding some fixed it.
I wonder if using a silica containing carbon-to-alloy paste such as Park Tool's SAC-2 would be helpful for this.

 

[Robert Holler]

Make sure you have three washers all on the outside of the clamp. Two on the sleeve side and one on the threaded bolt side.

 

[DrDave39]

Make sure you have three washers all on the outside of the clamp. Two on the sleeve side and one on the threaded bolt side.

Hmm. I disassembled it, and that is the layout, 2 on the sleeve and one on the threaded bolt side. I actually put another washer on the bolt side to se if that would give it more leverage....I'm going to disassemble it again and try cleaning the whole area with degreaser, and maybe adding the SAC-2 Matt Fry suggested?

 

[onmyback]

I've found that when I'm adjusting that clamp, more than a few mm, I need to release the front wheel quick release and BB clamps.

 

[benphyr]

I believe this is the order:
-Release all three pivot points (axle, BB, boom clamp)
-Adjust boom and/or slider,
-Tighten axle quick release,
-Tighten bottom bracket clamps (equal gap, not too tight, but not loose enough to vibrate loose either).
-You may need to loosen the boom and/or slider clamps again now to align your handlebar. (Since you are not changing the extension of the boom or the angle of the pivot points you should not need to loosen the axle and BB.)