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Old 03-10-08, 02:05 PM   #1
Thumpic 
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Treading the thin line of stem safety.........

I am trying to get a more comfortable position on my bike. I think it is the correct size as the stand over leaves about an inch between the top tube and the honeymoon hardware. But I have a generous gut (not as bad as my avatar) and would like to sit more upright.

I understand the mechanics of how the stem works with the wedging action between the anchor nut; the bottom of the stem and the fork tube. It appears that I can raise the stem another inch (easily) past the safety line and still maintain the mechanical integrity of the stem/fork tube attachment. Is there some other factor to consider?? All the parts are clean and lubed so I am sure of a firm assembly between the two components.

Thanks for your help!!!

btw....'85 Panasonic DX3000...............
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Old 03-10-08, 02:38 PM   #2
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I wouldn't do it. The "minimum insertion" line is there for a reason. Either get a longer stem or a stem extension.
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Old 03-10-08, 03:17 PM   #3
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Worst case scenario: Your estate will have a hard time winning a judgment against the stem manufacturer if you raise it 1" above the line.
Search for a longer stem.
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Old 03-10-08, 03:41 PM   #4
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Bike shops in my area usually have a supply of used threaded stems of various sizes that they will trade at a modest fee.

Al
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Old 03-10-08, 04:24 PM   #5
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Nitto Technomic
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Old 03-10-08, 04:29 PM   #6
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Nitto Technomic
My answer too. Do it right the first time.
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Old 03-10-08, 06:04 PM   #7
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Your stem may appear to be seated securely inside the steerer tube 1" about minimum insertion, but the wedge is pushing against the weaker, threaded section of the steerer tube.
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Old 03-10-08, 08:34 PM   #8
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Your stem may appear to be seated securely inside the steerer tube 1" about minimum insertion, but the wedge is pushing against the weaker, threaded section of the steerer tube.
That's absolutely correct and a recipe for catastrophic failure. Either get the Nitto Technomic stem recommended above or Profile Design's H2O, an up-angled stem that also has a long quill.
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Old 03-10-08, 09:18 PM   #9
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Yup. It seems like you can go higher. But the threaded portion of the stem is significantly weaker than the lower portion. When it goes, it goes catastrophically. A cheapo new or used stem at the LBS is a much better deal than dentures.

jim

p.s., I a hack at heart so its not just a knee-jerk reaction to advise against it. Plus, if you are big and strong, you really need to have trustworthy bars and stem.
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Old 03-11-08, 09:53 AM   #10
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You need a Nitto Technomic, probably the deluxe, if you're not planning on raising the bars a lot.
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Old 03-11-08, 01:30 PM   #11
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Oh the heck with all the worry warts here. That line is there only because lawyers made them put it there.



Besides, they can do incredible things these days with dental surgery.
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Old 03-11-08, 01:37 PM   #12
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thanks.............finally somebody said that "nitto technomic" was a stem..........I didn't know what the hell you first guys were talking about until then.......I'll get a new taller stem................Thanks for the advice...........
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