Q45 frozen boom problem
- Thread starter camineet
- Start date
Decher Kritzmire
Member
Without speculating why yours is frozen I can say that my boom will drop forward on its own when the bolts are loosened so here's what I would do. . In whatever order you like, I would apply some penetrating lub and let it soak down into that joint. Tighten back up the upper clamp to hold that part secure, fully disconnect the bottom bracket clamps and completely dislodge the chain stays so that you can get a hold of the curved bottom bracket portion and apply some twisting force. If it comes free you can then observe the slotted portion and see if it's been deformed though that would take some real force to damage.
cruzKurt
Guru
FYI, if I loosened that up on my v20 or v20c it will slide without effort.
JerseyJim
Guru
What I would do is snug up the handlebars, they are not part of the triangle that would cause the boom and slider to have a problem and you will need the handlebars for leverage. Once you do, try to rotate the handlebars to see if you can break the friction between the boom and slider. It shouldn't take much force so if it doesn't move, go on to the next step.
If the slider doesn't rotate, pull the slider back further through the stem clamp toward the seat and see if it breaks loose as the angle changes.
If you can't break it free doing that, remove the stem clamp so that you can move the boom and slider out of the "triangle" configuration. You may want a second set of hands to hold the boom while you again rotate the slider using the handlebars. The slider and boom should move freely now that it can stay parallel to the slider.
I had a similar thing happen during a build I just finished. The boom was too long to move freely inside the slider with the pivot points set. Instead of the boom and slider moving along the same axis, the boom is forced against the inner face of the slider and wedges in. Its a matter of geometry. The chainstay moves in an arc, not a straight line. The boom and slider are pinned at the stem, so the range of sliding that can happen as the chainstay traverses the arc is limited. You have to change the relationship between the stem clamp and the slider to get the boom and slider to move in parallel along the same axis. It will not do this throughout the entire range marked on the slider without some manipulation.
Incidentally, in my case, in order to get my fit, I had to cut off 4.5 inches off the boom because it would have overlapped the bottle mount holes on the slider. I'm on the shorter side (5'-7").
Hope this helps.
If the slider doesn't rotate, pull the slider back further through the stem clamp toward the seat and see if it breaks loose as the angle changes.
If you can't break it free doing that, remove the stem clamp so that you can move the boom and slider out of the "triangle" configuration. You may want a second set of hands to hold the boom while you again rotate the slider using the handlebars. The slider and boom should move freely now that it can stay parallel to the slider.
I had a similar thing happen during a build I just finished. The boom was too long to move freely inside the slider with the pivot points set. Instead of the boom and slider moving along the same axis, the boom is forced against the inner face of the slider and wedges in. Its a matter of geometry. The chainstay moves in an arc, not a straight line. The boom and slider are pinned at the stem, so the range of sliding that can happen as the chainstay traverses the arc is limited. You have to change the relationship between the stem clamp and the slider to get the boom and slider to move in parallel along the same axis. It will not do this throughout the entire range marked on the slider without some manipulation.
Incidentally, in my case, in order to get my fit, I had to cut off 4.5 inches off the boom because it would have overlapped the bottle mount holes on the slider. I'm on the shorter side (5'-7").
Hope this helps.
Wow interesting yes that makes sense about the movement limitations based on alignment. I actually have been able to get the boom to twist and adjust, but only by one milimeter at a time. I probably could resolve this issue entirely by changing the positioning to relive the wedge effect. Anyway, I've managed to get the setup to be adjustable despite it not being fluid at all like in the video. Thanks again for all the help from you guys!
