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I have a bike with ergononomic handles (Fuxon brand). Those are kept in position (as in prevented to rotate) with a mechanism which fits inside the handlebar.

This mechanism works by compressing two rubber cylinders along their axis, so they expand in the diameter.

Whenever I need to remove them for any reason (last time replacing the bar ends) it's a long battle. The rubber cylinders don't move even when the pressure is released. I risked many times ending with the rubber cylinders stuck inside the handlebar. Still, it takes no effort to push them in, but don't want this to happen again.

Any suggestion to prevent them to become stuck? Could I use some grease/lubricant, without making the situation worse or making them ineffective?

The current "solution" is to relieve pressure by unscrewing the thing, and wait. It took several weeks, until one day the thing came out by pulling. mechanism disassembled mechanism

  • Can you post a picture taken from the inner end (showing the bolt/nut)? – Deleted User Mar 24 '16 at 17:27
  • picture added. Some more details: I cannot really grasp the bolt, so I inefficiently pull the plastic end which in turn pulls the bolt. The force needed is really too much, and it seems that the more I pull the more the cylinders oppose. When partially unscrewed the bolt is free to move a few cm so i'm sure it's not pressing the cylinders. – kiwi Mar 24 '16 at 18:09
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    if you were going to grease anything i would recommend it be the actual bolt, could it be that once the rubber expands it is also expanding into the threads on the bolt, which is in turn greatly reducing its ability to shrink back down because of the friction with the threads? Does that even make sense? lol You could also try undoing the bolt and then trying something like a hair dryer to soften them up some. Both guesses on my part. – Nate W Mar 24 '16 at 18:22
  • I've run into this general scenario easily a dozen times, rehabbing old bikes where the end plugs need to be removed for one reason or another. I've never found a good solution. – Daniel R Hicks Mar 24 '16 at 19:12
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Grease would make the rubber slip, defeating the purpose of the mechanism. And it might cause the rubber to deteriorate.

Best solution is to just throw these grips in the garbage, and get some better-designed ones. I've seen several types that use an external clamp (or two clamps) to hold the grip in place - I'm sure that would work better.

But if you're really set on keeping these grips, and don't mind getting "creative", you might be able to make an alternate locking mechanism. The expansion plugs that they use with carbon steering tubes would be ideal - except they're too big. So you want something that works on the same principle, but fits inside the handlebar. Go to the fastener section at a hardware store, and see if you can find expansion bolts that are the right size.

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    This is meant to expand behind a wall and stay in place. Threading the bolt back through will not unexpand it. This would end up "permanently" installed in the bar. – Deleted User Mar 28 '16 at 17:08
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I can't see how this would ever work (on it's own) for loosening. It appears to be a poor design. When tightening, the compression from the rubber rings might/should provide enough tension to hold the nut in place while the bolt turns. When loosening, I don't see anything to hold the nut in place. IE, when you turn the bolt, there is nothing to stop the nut from turning as well and not actually loosening. You may try pulling on the end cap with one hand while loosening the bolt with the other. It may provide enough tension to hold the nut in place while you turn the bolt. If not, I'd look into finding a method for attaching the nut to the washer and/or the rings so that something is holding the nut in place while you loosen the bolt.

I would not recommend ANY lubricant to the rubber parts (would likely just make the attachment less effective). However, a very small amount of lubricant for the nut/bolt interface may help some.

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Maybe don't tighten them up so much next time? Can you use fewer of the rubber doughnuts on the bolt? Or replace the middle doughnuts with a short piece of tube?

Are you wedded to these handgrips - you might find a new replacement with a better mounting system.

Final resorts: if you're handy might be to remove the axis bolt and doughuts completely, and drill a small radial hole through your bars and through the plastic end. Then use a suitable tiny bolt or a screw from each side to retain the end.

Do you have straight bars? Could you use one really long chicago bolt all the way through to hold both ends on?

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    Perhaps replacing them is the only thing to do. I didn't find replacements which are both ergo and don't prevent installation of end bars though. Drilling is not an option, It's an aluminium bar and I prefer to not alter it. The bar is straight enough for a chicago bolt I think, but I'm not sure if the traction alone would prevent the grips from rotating when the hand is putting pressure on them. – kiwi Mar 25 '16 at 8:23
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    The problem is the rubber gets more or less welded to the inside of the bar. And most schemes that one thinks MIGHT work would require abandoning the nut on the far side to remove the bolt and insert something else, a bad move if scheme doesn't work and you have to go back tugging on the bolt (which is now no longer connected to the nut). – Daniel R Hicks Mar 25 '16 at 12:30
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    And you often need to remove a perfectly good grip to replace a lever or some such, so cutting the grip off is not a really good option. – Daniel R Hicks Mar 25 '16 at 12:32
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    @Criggie - This is pretty much the only system I've seen for bikes in this category. – Daniel R Hicks Mar 26 '16 at 0:09
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    I've seen ergo grips with a better "lock-on" style attachment method (pinch clamp on the outside). – Deleted User Mar 28 '16 at 17:06

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