#1
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Movement in stem
I hope I've got my terminology right. I have a Shogun hybrid and I recently
changed the angle where the stem meets the fork. I dropped it so that the stem is now nearly horizontal (it was about 45° up), thus moving the handlebars a touch lower and further away from me. I adjusted the angle of the handlebars themselves to suit and then the bits attached to the handlebars. So far, so good. The problem is that there is now slight but perceivable movement in the stem, up or down depending on whether I'm leaning on or pulling back the handlebars. It's most disconcerting. There are two relevant bolts, one horizontal through the circular bits at the fork end and one underneath the stem and vertical to it, that I've tightened to the point where I fear my Allen key is about to snap, yet there is still this movement. Is this normal? Or have I buggered something up? -- A: Top-posters. Q: What is the most annoying thing on Usenet? |
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#2
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Movement in stem
DRS wrote:
I hope I've got my terminology right. I have a Shogun hybrid and I recently changed the angle where the stem meets the fork. I dropped it so that the stem is now nearly horizontal (it was about 45° up), thus moving the handlebars a touch lower and further away from me. I adjusted the angle of the handlebars themselves to suit and then the bits attached to the handlebars. So far, so good. The problem is that there is now slight but perceivable movement in the stem, up or down depending on whether I'm leaning on or pulling back the handlebars. It's most disconcerting. There are two relevant bolts, one horizontal through the circular bits at the fork end and one underneath the stem and vertical to it, that I've tightened to the point where I fear my Allen key is about to snap, yet there is still this movement. Is this normal? Or have I buggered something up? The horizontal bolts are not meant to be loosened or tightened. They are torqued on precisely and are not needed to make adjustments to the stem. The vertical bolt underneath is the only one you should need to adjust. It probably clamps down on a grooved piece which locks the stem into place when the grooves are engaged. If this is tight, and the grooved piece is seated properly, you should take your bike into a LBS to have it looked at, a stem is not a nice thing to have break. |
#3
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Movement in stem
Jacobe Hazzard wrote in message
le.rogers.com DRS wrote: [...] The problem is that there is now slight but perceivable movement in the stem, up or down depending on whether I'm leaning on or pulling back the handlebars. It's most disconcerting. There are two relevant bolts, one horizontal through the circular bits at the fork end and one underneath the stem and vertical to it, that I've tightened to the point where I fear my Allen key is about to snap, yet there is still this movement. Is this normal? Or have I buggered something up? The horizontal bolts are not meant to be loosened or tightened. They are torqued on precisely and are not needed to make adjustments to the stem. Rightly or wrongly, if I don't loosen the horizontal bolt somewhat then I can't adjust the angle of the stem even if the vertical bolt is removed. The vertical bolt underneath is the only one you should need to adjust. It probably clamps down on a grooved piece which locks the stem into place when the grooves are engaged. If this is tight, and the grooved piece is seated properly, you should take your bike into a LBS to have it looked at, a stem is not a nice thing to have break. I loosened both bolts, reseated everything and retightened them. It seems to have done the trick. -- "I'm proud that I live in a country where witnessing two hours of bloody, barbarous torture in gloating detail is considered indicia of religious piety, whereas a mere second gazing upon a woman's breast is cause for outraged apoplexy." Betty Bowers, http://www.bettybowers.com/melgibsonpassion.html |
#4
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Movement in stem
Jacobe Hazzard wrote in message
le.rogers.com DRS wrote: [...] The problem is that there is now slight but perceivable movement in the stem, up or down depending on whether I'm leaning on or pulling back the handlebars. It's most disconcerting. There are two relevant bolts, one horizontal through the circular bits at the fork end and one underneath the stem and vertical to it, that I've tightened to the point where I fear my Allen key is about to snap, yet there is still this movement. Is this normal? Or have I buggered something up? The horizontal bolts are not meant to be loosened or tightened. They are torqued on precisely and are not needed to make adjustments to the stem. Rightly or wrongly, if I don't loosen the horizontal bolt somewhat then I can't adjust the angle of the stem even if the vertical bolt is removed. The vertical bolt underneath is the only one you should need to adjust. It probably clamps down on a grooved piece which locks the stem into place when the grooves are engaged. If this is tight, and the grooved piece is seated properly, you should take your bike into a LBS to have it looked at, a stem is not a nice thing to have break. I loosened both bolts, reseated everything and retightened them. It seems to have done the trick. -- "I'm proud that I live in a country where witnessing two hours of bloody, barbarous torture in gloating detail is considered indicia of religious piety, whereas a mere second gazing upon a woman's breast is cause for outraged apoplexy." Betty Bowers, http://www.bettybowers.com/melgibsonpassion.html |
#5
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Movement in stem
You seem to be describing a quill type stem (that is inserted into the fork)
not a newer "A-headset" (externally clamped) type. In that case you should loosen completely the bolt clamping the stem into the fork (you may need to tap it to dislodge the wedge after you loosen it about 3 turns) and then you will be able to feel just how loose a fit in the fork it is. It should be shimmed to a very close (almost tight) fit. This is best done with brass shim stock of whatever thickness will allow its being wrapped completely around one time (usually about .003"-.006"), but can also be done with a scrap of aluminum flashing or even a beverage can. If you haven't got the ideal thickness you can overlap it. It's a good idea to taper the bottom end to facilitate insertion into the fork. The shim should end up as a cylinder around the very top of the steerer tube, right under the headset top nut, but if some is visible it won't hurt anything. It only needs to be about an inch in depth. When you re-tighten the wedge, you will have a wiggle-free connection. One last word: everything on a stem should be greased (threads, wedge, shim, inside of steerer) -except- for the bar-stem interface. Mark Pace Pace Bicycle Haven Independence, MO 64050 |
#6
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Movement in stem
You seem to be describing a quill type stem (that is inserted into the fork)
not a newer "A-headset" (externally clamped) type. In that case you should loosen completely the bolt clamping the stem into the fork (you may need to tap it to dislodge the wedge after you loosen it about 3 turns) and then you will be able to feel just how loose a fit in the fork it is. It should be shimmed to a very close (almost tight) fit. This is best done with brass shim stock of whatever thickness will allow its being wrapped completely around one time (usually about .003"-.006"), but can also be done with a scrap of aluminum flashing or even a beverage can. If you haven't got the ideal thickness you can overlap it. It's a good idea to taper the bottom end to facilitate insertion into the fork. The shim should end up as a cylinder around the very top of the steerer tube, right under the headset top nut, but if some is visible it won't hurt anything. It only needs to be about an inch in depth. When you re-tighten the wedge, you will have a wiggle-free connection. One last word: everything on a stem should be greased (threads, wedge, shim, inside of steerer) -except- for the bar-stem interface. Mark Pace Pace Bicycle Haven Independence, MO 64050 |
#8
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Movement in stem
MAPaceBike wrote in message
You seem to be describing a quill type stem (that is inserted into the fork) not a newer "A-headset" (externally clamped) type. In that case you should loosen completely the bolt clamping the stem into the fork (you may need to tap it to dislodge the wedge after you loosen it about 3 turns) and then you will be able to feel just how loose a fit in the fork it is. It should be shimmed to a very close (almost tight) fit. The bit that clamps onto the fork proper has three bolts, one vertical and two horizontal. Those I haven't touched. The point of interest is the hinge bit - where I changed the angle. That's where the one horizontal and one vertical bolts are. The movement (before I redid them) was not horizontal, it was vertical, up when I pulled on the handlebars and down when I leaned forward, pivoting on this hinge. The stem has "Tioga" on it but I can't find it on the Tioga website (or any other site for that matter) which is a right pain because I'd love to be able to show what it looks like. It's easy enough to find pictures of individual components but oddly enough I've yet to come across a site which has a decent picture of a bike with little arrows pointing to the various bits identifying what's what and where (and variations thereon). -- "I'm proud that I live in a country where witnessing two hours of bloody, barbarous torture in gloating detail is considered indicia of religious piety, whereas a mere second gazing upon a woman's breast is cause for outraged apoplexy." Betty Bowers, http://www.bettybowers.com/melgibsonpassion.html |
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