Bars slipping on quill stem

kingofthetailwind
kingofthetailwind Posts: 575
edited March 2013 in Workshop
Hi, I'm the proud new owner of a mint early 80's Viking Vision. :)

Yesterday morning I noticed the bars slipping downwards when I was on the hoods. (Or where the hoods would be if I had some!) No tools with me but I managed to ride it home safely enough.

I went to tighten the stem this morning before I left, but there wasn't much tightening to do. Got maybe half a turn on it and wouldn't want to force it any more. Despite this I'm fairly sure the bars slipped down again this morning. Only very slightly though.

Any advice? Has the clamp just gone?

Comments

  • Rodrego Hernandez
    Rodrego Hernandez Posts: 1,436
    What bar / stem combination is it?

    Some had a slightly different sizing so you had to use the same manufacturer for both bar and stem.

    Or the stem has stretched slightly / bars have shrunk.
  • kingofthetailwind
    kingofthetailwind Posts: 575
    Sakae Road Champion bars and an ITM stem.
  • maringirl
    maringirl Posts: 195
    Take stem out - it is held in place by an expander bolt so undo nut in top of stem and then hit with rubber hammer to dislodge the expander inside. Remove whole thing and clean it all up and clean inside the steerer tube on frame as well. Check expander bolt is moving easily up it's thread. Grease and refit.
  • onbike 1939
    onbike 1939 Posts: 708
    maringirl wrote:
    Take stem out - it is held in place by an expander bolt so undo nut in top of stem and then hit with rubber hammer to dislodge the expander inside. Remove whole thing and clean it all up and clean inside the steerer tube on frame as well. Check expander bolt is moving easily up it's thread. Grease and refit.

    I suspect the OP may be referring to the bars rotating rather than slipping on the steering tube. If this is the case then it may be that the match between bars and stem is amiss. The use of an appropriate shim could be the answer.
  • kingofthetailwind
    kingofthetailwind Posts: 575
    onbike 1939 wrote:
    maringirl wrote:
    Take stem out - it is held in place by an expander bolt so undo nut in top of stem and then hit with rubber hammer to dislodge the expander inside. Remove whole thing and clean it all up and clean inside the steerer tube on frame as well. Check expander bolt is moving easily up it's thread. Grease and refit.

    I suspect the OP may be referring to the bars rotating rather than slipping on the steering tube. If this is the case then it may be that the match between bars and stem is amiss. The use of an appropriate shim could be the answer.

    Yeah, they're rotating. Sorry if that wasn't clear.

    Something like this?

    http://www.edinburghbicycle.com/product ... lebar-shim
  • onbike 1939
    onbike 1939 Posts: 708
    Yes, that's the thing.
  • kingofthetailwind
    kingofthetailwind Posts: 575
    Cool, thanks for the respones.
  • proto
    proto Posts: 1,483
    Decent pair of scissors and an old Coke can will do the job just as well.
  • kingofthetailwind
    kingofthetailwind Posts: 575
    Diet or regular? :)

    Thanks, that sounds much more my budget!
  • Monty Dog
    Monty Dog Posts: 20,614
    Coke Can shim was the regular cure back in the day. You'll likely need to put a screwdriver into the clamp slot to open-it out a litte to slide the shim into place.
    Make mine an Italian, with Campagnolo on the side..
  • onbike 1939
    onbike 1939 Posts: 708
    Monty Dog wrote:
    Coke Can shim was the regular cure back in the day. You'll likely need to put a screwdriver into the clamp slot to open-it out a litte to slide the shim into place.

    I agree and use this method still.

    I think Pirsig was spot on.
  • kingofthetailwind
    kingofthetailwind Posts: 575
    Thanks guys, I'll do this at the weekend.

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