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  1. #1
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    Thomson Stem Problems

    Has anyone here had this problem?

    I've been using a Thomson (Don't buy the stem from Jensen) stem on my 5 Spot for about 1 year. The stem constantly loosens up. I have to tighten the steerer clamp screws before every ride. If I don't, the headset starts creaking after a couple of rides. When I check the screws for torque, they're always looser than spec.

    Thomson asked me to send it to them, but I don't believe that it will help. I went out and bought a new Thomson stem and I have the same issues...What gives?

    The stem is used with a Cane Creek headset and a Marzocchi Z1FR (2003) (Don't buy the fork from Jensen) .

    Any help or suggestions would be appreciated. Does anyone have any good stem recommendations? I need a 100 X 5*.

  2. #2
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    Quote Originally Posted by WarrGuru
    Has anyone here had this problem?

    I've been using a Thomson (Don't buy the stem from Jensen) stem on my 5 Spot for about 1 year. The stem constantly loosens up. I have to tighten the steerer clamp screws before every ride. If I don't, the headset starts creaking after a couple of rides. When I check the screws for torque, they're always looser than spec.

    Thomson asked me to send it to them, but I don't believe that it will help. I went out and bought a new Thomson stem and I have the same issues...What gives?

    The stem is used with a Cane Creek headset and a Marzocchi Z1FR (2003) (Don't buy the fork from Jensen) .

    Any help or suggestions would be appreciated. Does anyone have any good stem recommendations? I need a 100 X 5*.
    Okay so you don't like Jensen...what happened? they always did good by me.

    As for the Th0mson stem, y'know I also have a '03 Z1 and have used four different Th0mson stems (different sizes and rises) and haven't had any problem keeping them tight. I use a CK headset but if the stem is a problem the headset shouldn't be part of the equasion.

    Question, do you grease anything on your stem? You should grease the stem clamp screws but never grease the clamp itself or the steerer tube.

    This is a strange problem I'd recommend trying another Th0mson stem. Either a loaner from a friendly lbs or swapping with Th0mson direct. Sorry I don't have better advice.
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  3. #3
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    Quote Originally Posted by Bikezilla
    Question, do you grease anything on your stem? You should grease the stem clamp screws but never grease the clamp itself or the steerer tube.
    Before installing my stem, I always clean the steerer tube and inside of the clamping mechanism with alcohol - just to make sure there is no grease residue.

  4. #4
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    Quote Originally Posted by Bikezilla
    Okay so you don't like Jensen...what happened? they always did good by me.

    As for the Th0mson stem, y'know I also have a '03 Z1 and have used four different Th0mson stems (different sizes and rises) and haven't had any problem keeping them tight. I use a CK headset but if the stem is a problem the headset shouldn't be part of the equasion.

    Question, do you grease anything on your stem? You should grease the stem clamp screws but never grease the clamp itself or the steerer tube.

    This is a strange problem I'd recommend trying another Th0mson stem. Either a loaner from a friendly lbs or swapping with Th0mson direct. Sorry I don't have better advice.
    Hi Zilla,

    The Jensen thing is just a response to the MTBR alteration of my post.

    Anyway. I went to performance last week and bought a new Thoms0n stem. Same issue. The spacers under the clamp have different OD's....can that cause a problem?

    I made sure that the screws were greased and that the inside of the clamp was free of any grease. Remember......the screws seem to be getting loose. I catch it now before it gets too loose. I suppose that my torque wrench may be off, but I torqued the screws up to 60 in-lbs (per Thoms0n) and they still came loose. I've never had this issue before.

    I did read a couple of reviews (product reviews) where some users complained about the stem constantly coming loose. I wonder what caused the issues.

    I have trouble believing that I ride more aggressively than you or others here. I'm just an old phart that likes to ride fast.

  5. #5
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    Quote Originally Posted by WarrGuru
    Has anyone here had this problem?
    I'm not a big fan of Thomson_ stem either. The clamp is a bit of a hassle to tighten (compared to other stems), with no apparent benefit.

    I had some problems with my Thomsonn stem loosening up as well, but my problems were due to improper installation. Once I got that sorted, I didn't have any more problems (mine has been tight for months).

    Your problem sounds different from mine, but here are a couple of things to check. I was using a King headset, and the King headset has an o-ring that goes on the steer tube. When I initially assembled my bike, I left the o-ring out (I mistakenly assumed it was simply a seal to keep dirt out), because I wasn't sure of the steer tube length, and I figured I would have the fork on and off a few times before I got things sorted. Anyway, it turns out that the o-ring is not simply a seal. It also prevents any lateral play in the top of the steer tube. It was this lateral play that caused my stem to loosen up. I'm not sure how your headset goes together, but you should check to see that you don't have any lateral play in the headset before you torque down the stem.

    Also, I put a good coating of grease on my bolts before I put them in. However, with the design of the Thomson_ clamp, if you have too much grease on the bolts, when you tighten the clamp, it will squeeze the grease out of the inside of the clamp onto the steer tube. So, even if the steer tube is clean when you put the stem on, it won't be once you get it torqued down. So, don't use too much grease on the bolts.

    Now that I have resolved these two problems, my stem has remained tight. However, I won't be buying any more Thomson_ stems. Too much hassle. As far as a replacement. If your looking for something strong, the Race_Face Deus looks nice, and is supposed to be a bit stiffer than the Thomson_. If your looking for something light, the Syntace F99 looks nice.

    https://terrengsykkel.no/img/guide/t...03_deus_01.jpg

  6. #6
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    Quote Originally Posted by Tullebukk
    I'm not a big fan of Thomson_ stem either. The clamp is a bit of a hassle to tighten (compared to other stems), with no apparent benefit.

    I had some problems with my Thomsonn stem loosening up as well, but my problems were due to improper installation. Once I got that sorted, I didn't have any more problems (mine has been tight for months).

    Your problem sounds different from mine, but here are a couple of things to check. I was using a King headset, and the King headset has an o-ring that goes on the steer tube. When I initially assembled my bike, I left the o-ring out (I mistakenly assumed it was simply a seal to keep dirt out), because I wasn't sure of the steer tube length, and I figured I would have the fork on and off a few times before I got things sorted. Anyway, it turns out that the o-ring is not simply a seal. It also prevents any lateral play in the top of the steer tube. It was this lateral play that caused my stem to loosen up. I'm not sure how your headset goes together, but you should check to see that you don't have any lateral play in the headset before you torque down the stem.

    Also, I put a good coating of grease on my bolts before I put them in. However, with the design of the Thomson_ clamp, if you have too much grease on the bolts, when you tighten the clamp, it will squeeze the grease out of the inside of the clamp onto the steer tube. So, even if the steer tube is clean when you put the stem on, it won't be once you get it torqued down. So, don't use too much grease on the bolts.

    Now that I have resolved these two problems, my stem has remained tight. However, I won't be buying any more Thomson_ stems. Too much hassle. As far as a replacement. If your looking for something strong, the Race_Face Deus looks nice, and is supposed to be a bit stiffer than the Thomson_. If your looking for something light, the Syntace F99 looks nice.

    https://terrengsykkel.no/img/guide/t...03_deus_01.jpg
    Interesting thought about the o-ring. My cane Creek HS doesn't seem to have any o-ring. I don't understand how an o-ring could cause an issue. I'm confused about the o-ring. The lateral play may be something to look into. This is driving me nuts.

  7. #7
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    I've found that the torque needs to be checked several times during initial install. Tighten one side, then tighten the other. This seems to loosen the initial bolt so I go back and forth several times until everything is nice & snug. I doubt it has anything to do with your headset or spacers.

    In 3 years of using Thomson posts on several bikes I have never had one of their stems loosen. Try the back & forth method before giving up on the stem.

  8. #8
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    Quote Originally Posted by WarrGuru
    I made sure that the screws were greased and that the inside of the clamp was free of any grease. Remember......the screws seem to be getting loose. I catch it now before it gets too loose. I suppose that my torque wrench may be off, but I torqued the screws up to 60 in-lbs (per Thoms0n) and they still came loose. I've never had this issue before.
    I'm stumped. Maybe it is the headset stem combination, due to lateral play as mentioned Tulle' ...I have no idea.

    I have to say I find the Th0mson stem clamp rather useful in comparison...I've slammed my knee into the back of my stem many times...if it had been one that had projecting bolts or pointed clamp parts....yiiiieeee...

    It dosen't sound like you're doing anything wrong. If it is a freak stem/headset incompatibility then perhaps your best bet is to go with another clamp as you suggest. The good news is you can probably mount and test a stem w/o marking it up and return it in new condition if it dosen't work out. And the RF stems can be had for cheap.

    G'luck 'G
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  9. #9
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    Quote Originally Posted by WarrGuru
    Interesting thought about the o-ring. My cane Creek HS doesn't seem to have any o-ring. I don't understand how an o-ring could cause an issue. I'm confused about the o-ring. The lateral play may be something to look into. This is driving me nuts.
    I just remembered, I have a RaceFace Prodigy stem that I never used...I think it's 100x5 I'll check it out when I get home and let you know.
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  10. #10
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    Just so you know

    Quote Originally Posted by The Squeaky Wheel
    I've found that the torque needs to be checked several times during initial install. Tighten one side, then tighten the other. This seems to loosen the initial bolt so I go back and forth several times until everything is nice & snug. I doubt it has anything to do with your headset or spacers.

    In 3 years of using Thomson posts on several bikes I have never had one of their stems loosen. Try the back & forth method before giving up on the stem.
    I'm somewhat obsessive-compulsive when it comes to working on the bike. I not only go back and forth with the torque wrench......I do it in such small increments that it takes forever to get them both tight. I also tried larger increments....degreasing the inside...lubing the bolts and nuts...making sure that no lube gets on clamp, degrease with alcohol, <7mm from top of steerer to top of clamp. 48 in-lbs, 50 in-lbs, 60 in-lbs.....after a ride or 2 the screws need to be re-torqued. I even bought a new Thoms0n stem and it has the same issues.

    If it has nothing to do with the headset or spacers...AND my steerer tube is in spec (1.125"), then it only leaves the stem and the usage. I'm not going to ease up on the riding, so now what?

  11. #11
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    Thanks

    Quote Originally Posted by Bikezilla
    I just remembered, I have a RaceFace Prodigy stem that I never used...I think it's 100x5 I'll check it out when I get home and let you know.
    I appreciate the effort!

  12. #12
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    I know Thomson says not to, but why can't you apply a thin coat of grease on the steerer and stem clamps? I have since I've been running their stems with no problems, it eliminates the creaky noises.

    WarrGuru- I agree with Squeaky wheel, you need to tighten back and forth equally. When you tighten one side, the other loosens up.

  13. #13
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    Quote Originally Posted by rroeder
    I know Thomson says not to, but why can't you apply a thin coat of grease on the steerer and stem clamps?


    I'd have to agree with 'Zilla on this one, "never grease the clamp itself or the steerer tube." To the contrary, I do just the opposite and lightly roughen up the steer tube with a fine grit sandpaper. I also grease all the bolts, including the ones in the face plate, and then before I slip the stem on the steer tube I nuke 'em both with a degreaser. I've never had one loosen up on me yet.

  14. #14
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    Quote Originally Posted by Tullebukk
    I'm not a big fan of Thomson_ stem either. The clamp is a bit of a hassle to tighten (compared to other stems), with no apparent benefit.

    I had some problems with my Thomsonn stem loosening up as well, but my problems were due to improper installation. Once I got that sorted, I didn't have any more problems (mine has been tight for months).

    Your problem sounds different from mine, but here are a couple of things to check. I was using a King headset, and the King headset has an o-ring that goes on the steer tube. When I initially assembled my bike, I left the o-ring out (I mistakenly assumed it was simply a seal to keep dirt out), because I wasn't sure of the steer tube length, and I figured I would have the fork on and off a few times before I got things sorted. Anyway, it turns out that the o-ring is not simply a seal. It also prevents any lateral play in the top of the steer tube. It was this lateral play that caused my stem to loosen up. I'm not sure how your headset goes together, but you should check to see that you don't have any lateral play in the headset before you torque down the stem.

    Also, I put a good coating of grease on my bolts before I put them in. However, with the design of the Thomson_ clamp, if you have too much grease on the bolts, when you tighten the clamp, it will squeeze the grease out of the inside of the clamp onto the steer tube. So, even if the steer tube is clean when you put the stem on, it won't be once you get it torqued down. So, don't use too much grease on the bolts.

    Now that I have resolved these two problems, my stem has remained tight. However, I won't be buying any more Thomson_ stems. Too much hassle. As far as a replacement. If your looking for something strong, the Race_Face Deus looks nice, and is supposed to be a bit stiffer than the Thomson_. If your looking for something light, the Syntace F99 looks nice.

    https://terrengsykkel.no/img/guide/t...03_deus_01.jpg

    Interesting.....I do have some lateral play....before I tighten the stem or bearing preload. I thought that a little play was normal. The lateral play seems to go away when I tighten the preload and steerer clamp bolts. Can you go into more detail about later play. How much should there be?

    Did you say that the lack of an o-ring (lateral play) caused your Thoms0n to get loose? You may be onto something here. Please elaborate!!!

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    This may be a bad idea, but... what about cleaning everything really well and then use a couple of drops of blue loctite on the bolts. It would allow disassembly without problem and may be enough to prevent them from coming loose.

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    Funny you should mention that

    Quote Originally Posted by jennasdad
    This may be a bad idea, but... what about cleaning everything really well and then use a couple of drops of blue loctite on the bolts. It would allow disassembly without problem and may be enough to prevent them from coming loose.
    I'm down to my last straw, so that's exactly what I'm going to do. Loctite.

  17. #17
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    Cool-blue Rhythm

    Quote Originally Posted by Blue Shorts
    I'm down to my last straw, so that's exactly what I'm going to do. Loctite.
    Loctite isn't the answer

    Help's on the way...check your PM...
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  18. #18
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    Usually they suffer from the opposite problem...

    ....typically they stay tight and make stripping sounds when you try to loosen them.
    I would tighten and try marking the top of each bolt with some white out or something similar. This will allow you to see if the bolt is actually turning.
    Once tightening the threads to a point where they are snug you should rotate the tightening in 1/8 turn increments.
    You could have a hairline crack at one of your welds or there is a minute chance that the stem could be slightly out of alignment.
    A caliper may indicate that your steer tube is slightly out of round thus making the clamping device not seat as tightly as it should.
    I would try the stem on a friends bike to see if the issue follows the stem.
    Thomson uses their clamping system because most stems that fail do so at the welds or where the binding bolts are. Using the cam lock lowers the stress on those key areas.
    The issue would drive me crazy until I figured it out. Guessing, I'd be that the issue is not with the stem.

  19. #19
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    Quote Originally Posted by WarrGuru
    Interesting.....I do have some lateral play....before I tighten the stem or bearing preload. I thought that a little play was normal. The lateral play seems to go away when I tighten the preload and steerer clamp bolts. Can you go into more detail about later play. How much should there be?

    Did you say that the lack of an o-ring (lateral play) caused your Thoms0n to get loose? You may be onto something here. Please elaborate!!!
    I've never used a cane creek headset, but I would think you should not have any lateral play at all. If you do, the steer tube will rock back and forth in the headset and eventually loosen up the stem. I could ride for about an hour before I would start hearing some ticking sounds from the headset and I could tell it was getting loose. The way I finally tracked down the problem, was by putting a different stem on. Sure enough, that stem got loose as well, so I knew it wasn't the stem that was the problem (although it did stay tight about 3 times as long as the Thomson_).

    Most headsets have something that goes under (or inside) the upper bearing cap to prevent lateral play. Either an o-ring or a compression ring of some type. Maybe yours is missing?

    On the King headsets, the inside diameter of the upper bearing is larger than the outside diameter of the steer tube, so without the o-ring, the steer tube can rock back and forth inside the headset. The o-ring goes inside the upper bearing cap. It's a tight fit. You have to tap the upper bearing cap on and off with a hammer. But, once it's on, there is no lateral play. You can see the groove for the o-ring in the upper bearing cap in the diagram below:

    <img src="https://gallery.consumerreview.com/webcrossing/images/headset-d.jpg">


    I've never used a Cane Creek headset, but from looking at the diagrams on their website, it looks like some of their headsets use o-rings, and some use compression rings. I have a headset with a compression ring (it looks like a circular plastic wedge that goes around the steer tube under the upper bearing cap), and after you tighten the preload with the stem top cap, you can remove the stem and you have to tap the steerer out with a hammer to remove it. It's that tight of a fit, so there is no lateral play at all. You can see the compression ring(s) in the diagram(s) below (#3):

    <img src="https://gallery.consumerreview.com/webcrossing/images/headset-a.jpg">


    And maybe a bit better here (#7):

    <img src="https://gallery.consumerreview.com/webcrossing/images/headset-e.jpg">


    It does look like some of the Cane Creek headsets use an o-ring as well. It looks like you can see a groove for the o-ring in the upper bearing cap in the diagram below:

    <img src="https://gallery.consumerreview.com/webcrossing/images/headset-b.jpg">


    And the instructions for the S5 headset refer to an o-ring:

    <img src="https://gallery.consumerreview.com/webcrossing/images/headset-c.jpg">


    You should verify that you have either an o-ring or compression ring in your headset. Perhaps yours is missing. You might also try another stem. If it loosens up as well, then you can pretty much rule out the stem.
    Last edited by Tullebukk; 06-02-2004 at 07:49 AM.

  20. #20
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    Quote Originally Posted by Tullebukk
    I've never used a cane creek headset, but I would think you should not have any lateral play at all. If you do, the steer tube will rock back and forth in the headset and eventually loosen up the stem. I could ride for about an hour before I would start hearing some ticking sounds from the headset and I could tell it was getting loose. The way I finally tracked down the problem, was by putting a different stem on. Sure enough, that stem got loose as well, so I knew it wasn't the stem that was the problem (although it did stay tight about 3 times as long as the Thomson_).

    Most headsets have something that goes under (or inside) the upper bearing cap to prevent lateral play. Either an o-ring or a compression ring of some type. Maybe yours is missing?

    On the King headsets, the inside diameter of the upper bearing is larger than the outside diameter of the steer tube, so without the o-ring, the steer tube can rock back and forth inside the headset. The o-ring goes inside the upper bearing cap. It's a tight fit. You have to tap the upper bearing cap on and off with a hammer. But, once it's on, there is no lateral play. You can see the groove for the o-ring in the upper bearing cap in the diagram below:

    <img src="https://gallery.consumerreview.com/webcrossing/images/headset-d.jpg">


    I've never used a Cane Creek headset, but from looking at the diagrams on their website, it looks like some of their headsets use o-rings, and some use compression rings. I have a headset with a compression ring (it looks like a circular plastic wedge that goes around the steer tube under the upper bearing cap), and after you tighten the preload with the stem top cap, you can remove the stem and you have to tap the steerer out with a hammer to remove it. It's that tight of a fit, so there is no lateral play at all. You can see the compression ring(s) in the diagram(s) below (#3):

    <img src="https://gallery.consumerreview.com/webcrossing/images/headset-a.jpg">


    And maybe a bit better here (#7):

    <img src="https://gallery.consumerreview.com/webcrossing/images/headset-e.jpg">


    It does look like some of the Cane Creek headsets use an o-ring as well. It looks like you can see a groove for the o-ring in the upper bearing cap in the diagram below:

    <img src="https://gallery.consumerreview.com/webcrossing/images/headset-b.jpg">


    And the instructions for the S5 headset refer to an o-ring:

    <img src="https://gallery.consumerreview.com/webcrossing/images/headset-c.jpg">


    You should verify that you have either an o-ring or compression ring in your headset. Perhaps yours is missing. You might also try another stem. If it loosens up as well, then you can pretty much rule out the stem.
    My Headset (Cane Creek S2) does have the O-Ring. It's a snug fit, but 2 fingers is all I need to remove it.

    I did try another Thomson stem and it did get loose. I haven't tried another brand stem, yet. This is driving me nuts.

    Maybe there's enough play to loosen the Thomson, but not another type of stem?

    Thanks for all of the detail in your post!!!!!
    Last edited by Blue Shorts; 06-03-2004 at 06:14 AM.

  21. #21
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    Quote Originally Posted by Blue Shorts
    My Headset (Cane Creek S2) does have the O-Ring. It's a snug fit, but 2 fingers is all I need to remove it...
    I follow what Tulle's getting at but I don't fully understand how it could loosen a stem. On my Hardtail, I put on a super-el-cheapo Cane Creek headset and it has the compression ring. It's light soft Al and for me, it goes on and comes off easily, just like yours. My headset has loosened up a slight bit once or twice, but it did not affect the stem which is a Kore.

    As for the CK I pulled my fork off recently and it was quite easy to remove and reinstall the top cap. I did not need to tap anything. Neither the HS nor the stem ever loosens.

    Hmmm, this is tricky!
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  22. #22
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    Quote Originally Posted by Blue Shorts
    My Headset (Cane Creek S2) does have the O-Ring. It's a snug fit, but 2 fingers is all I need to remove it.

    I did try another Thomson stem and it did get loose. I haven't tried another brand stem, yet. This is driving me nuts.

    Maybe there's enough play to loosen the Thomson, but not another type of stem?

    Thanks for all of the detail in your post!!!!!
    Does it also have the compression ring? I can't find an exploded view of the C-2, but the exploded view below looks like it has both and o-ring in the upper cover and a compression ring. In the diagram below, it appears that the o-ring in the upper cover is simply a seal to keep out dirt, and the compression ring is responsible for eliminated play in the steer tube. However, I'm not sure.

    <img src="https://gallery.consumerreview.com/webcrossing/images/headset-e.jpg">

  23. #23
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    Quote Originally Posted by Bikezilla
    I follow what Tulle's getting at but I don't fully understand how it could loosen a stem.
    The odd thing is that his bolts are coming loose. My bolts didn't come loose, my stem just slowly worked it's way up the steer tube. However, I didn't ride for more than an hour or so before tightening the stem back up. So, I'm speculating that maybe if I had ridden a bit longer, the slight rocking back and forth of the stem may have loosened my bolts as wll, but then again maybe not.

    Perhaps the steer tube is dented. That may cause the problem. I do remember reading about someone that did dent their steer tube by over tightening a Thomson_ stem.

    As far as the CK headset. The steer tube on my Marzocchi fork has a rough surface (almost like sandpaper). That's probably why my cap is so hard to get on/off. I can't even get it to budge by hand.

  24. #24
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    And the mystery continues...

    Quote Originally Posted by Tullebukk
    The odd thing is that his bolts are coming loose. My bolts didn't come loose, my stem just slowly worked it's way up the steer tube. However, I didn't ride for more than an hour or so before tightening the stem back up. So, I'm speculating that maybe if I had ridden a bit longer, the slight rocking back and forth of the stem may have loosened my bolts as wll, but then again maybe not.

    Perhaps the steer tube is dented. That may cause the problem. I do remember reading about someone that did dent their steer tube by over tightening a Thomson_ stem.

    As far as the CK headset. The steer tube on my Marzocchi fork has a rough surface (almost like sandpaper). That's probably why my cap is so hard to get on/off. I can't even get it to budge by hand.
    Buzzzz! Nope, I have a Z1 and it has a very rough steerer tube too. No problems sliding the top cap. Blue's got the same deal. BTW Tulle, the tech diagrams were very helpful!

    Okay I think I can see how a slight rocking could lever up on the base of the stem and work it's way up. I would think with the preload and tightly clamped stem it would be difficult without a fair bit of play though...and still I'm not sure how it would loosen the clamp screws. Denting is a possibility. But if it were dented, he could still tighten the screws and tight is tight...right?...hmm unless the stem could rock itself loose under riding pressure. Gaaaah! Now this is bugging me!

    Blue, when your stem gets loose, is your headset loose too? Did your stem ride up the steerer tube as Tulle' describes?
    Faster is better, even when it's not.

  25. #25
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    Quote Originally Posted by Tullebukk
    Does it also have the compression ring? I can't find an exploded view of the C-2, but the exploded view below looks like it has both and o-ring in the upper cover and a compression ring. In the diagram below, it appears that the o-ring in the upper cover is simply a seal to keep out dirt, and the compression ring is responsible for eliminated play in the steer tube. However, I'm not sure.
    My S2 has the rubber o-ring AND the compression ring. If I remove the top cap, stem and spacers and just put a little downward pressure on the bike....the steerer does not move laterally..at least visibly The movement I saw before was when the bottom race was not fully seated in the bottom bearings....the whole top to the bearing assembly moved laterally. Once seated...there is no perceptable movement.

    I still think that you may be onto something. My other FS bike has a King headset. The dustcap / o-ring setup definitely fit much tighter than the Cane Creek. Maybe the Cane Creek moves enough to cause problems while the King does not. Lateral movement of the steerer tube might be able to rock the stem...forward and back....over and over....until it gets loose. Remember.....I'm guessing that most people that spend enought to install a Thomson Stem probably are also running a King HS....therefore no problem. (that's my theory and I'm sticking to it )

    I'm going to re-install the Thomson today and mark the screws to see if they're actually turning or if it's simply the clamp relaxing causing the screws to get loose.

  26. #26
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    Quote Originally Posted by Blue Shorts
    Lateral movement of the steerer tube might be able to rock the stem...forward and back....over and over....until it gets loose.

    I can't really think of anyway that the bolts could loosen up unless there is some movement there someplace. The only other thing I can think of, is perhaps the steer tube itself is dented and not allowing the clamp to sit flush on the steer tube. For example, if the bike shop overtightened the stem enough to dent the steer tube during preliminary assembly, and then added or removed a spacer under the stem during re-assembly, perhaps the surface wouldn't be flush under the clamp. But that's kind of a stretch. Or, if the steer tube itself was compressing, but that's even more of a stretch.

    Whatever you do, be careful. It can be a bit dangerous to ride with a loose stem. When I was still having problems with mine, it loosened up enough that in the middle of a short rocky descent, my front tire caught on a rock and the stem spun on the steer tube 90 degrees leaving the front tire perpendicular to the bike. Not exactly what you want during a rocky descent .

  27. #27
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    Quote Originally Posted by Bikezilla
    Buzzzz! Nope, I have a Z1 and it has a very rough steerer tube too. No problems sliding the top cap. Blue's got the same deal.
    Must just be production tolerances then. Mine was tight! After a couple of minutes of tapping, I only managed to get it to slide about 1/8" down the steer tube. It didn't seem right to me, so I decided to take it back off and ask King first (they never answered tho). But, I couldn't pull it or twist it off by hand. Had to use a hammer.


    Quote Originally Posted by Bikezilla
    Denting is a possibility. But if it were dented, he could still tighten the screws and tight is tight...right?...hmm unless the stem could rock itself loose under riding pressure. Gaaaah! Now this is bugging me!
    I don't know. Maybe if the bike shop dented it during inital assembly, and then later changed the number of spacers under the stem? Then the steer tube wouldn't be parallel to the surface of the clamp. I just can't really think of any way the bolts could come loose unless there was some movement someplace.

    It will be interesting to find out what the source of the problem is.

  28. #28
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    i didnt bother reading the whole thread, but it sounds like your doing nothing wrong. HOWEVER, thomsons are very easy to over tighten. and seeing as your running a fork that has a aluminum steerer, you may have dimpled you steer tube. if this is the case it wont be visible by eye. i had the same thing happen to me on a boxxer team last year. as far as the headset is conserned. it shouldnt be a part of the equasion. the way that you can tell if your st is dimpled is with a micrometer. good luck.

  29. #29
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    oh and as far as using grease on the steertube/inside of the clamp. DO NOT do this. also, using loctite is another very bad idea.

  30. #30
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    Quote Originally Posted by Tullebukk
    I can't really think of anyway that the bolts could loosen up unless there is some movement there someplace. The only other thing I can think of, is perhaps the steer tube itself is dented and not allowing the clamp to sit flush on the steer tube. For example, if the bike shop overtightened the stem enough to dent the steer tube during preliminary assembly, and then added or removed a spacer under the stem during re-assembly, perhaps the surface wouldn't be flush under the clamp. But that's kind of a stretch. Or, if the steer tube itself was compressing, but that's even more of a stretch.

    Whatever you do, be careful. It can be a bit dangerous to ride with a loose stem. When I was still having problems with mine, it loosened up enough that in the middle of a short rocky descent, my front tire caught on a rock and the stem spun on the steer tube 90 degrees leaving the front tire perpendicular to the bike. Not exactly what you want during a rocky descent .
    I think I'm gonna cut my losses. I'll try installing my Bontr@ger stem from another bike onto the Spot. That should tell me if simply changing stem types will solve the problem. If the answer is yes, then Bikezilla has graciously agreed to send me a 100 X 5* stem. I'll install the stem (racef@ce, I believe...and be done with it).

    If another stem does not solve the problem, then I'll have to look elsewhere. The Bontr@ger stem has massive bolts so that I can really torque it down. My gut is telling me that the Thoms0n stem really doesn't clamp as well as other stems, but used in conjunction with a good headset, it works well enough.

  31. #31
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    I don't like the small hardware and noise....

    Quote Originally Posted by WarrGuru
    Has anyone here had this problem?

    I've been using a Thomson (Don't buy the stem from Jensen) stem on my 5 Spot for about 1 year. The stem constantly loosens up. I have to tighten the steerer clamp screws before every ride. If I don't, the headset starts creaking after a couple of rides. When I check the screws for torque, they're always looser than spec.

    Thomson asked me to send it to them, but I don't believe that it will help. I went out and bought a new Thomson stem and I have the same issues...What gives?

    The stem is used with a Cane Creek headset and a Marzocchi Z1FR (2003) (Don't buy the fork from Jensen) .

    Any help or suggestions would be appreciated. Does anyone have any good stem recommendations? I need a 100 X 5*.
    You have to grease the crap out of their bolts or they creak. Also, you can't get at all heavy handed or you can bust something because of the small hardware. I also don't like the way you adjust the stem. Nonetheless, I'm a Thomson fan. I have never bent or broken either a stem or post. I have bent plenty of other posts. ]

    Is your steerer tube completely straight? No angle? Just a thought and comments.

    Jaybo

  32. #32
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    my friend, your problem is that you ARE using a torque wrench - just tighten down the stem steerer clamp bolts til they are TIGHT. If it still loosens up, tighten it up a little more!

    Torque setting are a baseline guide - not absolute. Feel the force! Let go......

    After living w/ two thompson stems for two years, I have never ever had any issues when I just cranked down on em til they were good to go.

  33. #33
    meh....
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    I have a Thomson stem that's never come loose. When I tighten it I tighten one side, then the other side, then the other side, then the other side. It seems to take about 4 trips left and right to get it tight. If you are torqueing one side to spec, then torqueing the other side to spec then stopping it will come loose for sure. You need to go side to side 3-4 times.

    Monte

  34. #34
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    Quote Originally Posted by Bikezilla

    Blue, when your stem gets loose, is your headset loose too? Did your stem ride up the steerer tube as Tulle' describes?
    Yes and no. Initially, that was the symptom. I'd be riding along and my headset would start to creak. I'd get home and re-do the preload and tighten the stem. Eventually, I started checking the stem bolts before each ride.

    So it appears that the stem screws loosen first and then the headset loosens. Sounds like movement to me.

    I now have to decide if I just want to switch stems, or do a few experiments, first.

  35. #35
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    Quote Originally Posted by jokermtb
    my friend, your problem is that you ARE using a torque wrench - just tighten down the stem steerer clamp bolts til they are TIGHT. If it still loosens up, tighten it up a little more!

    Torque setting are a baseline guide - not absolute. Feel the force! Let go......

    After living w/ two thompson stems for two years, I have never ever had any issues when I just cranked down on em til they were good to go.
    After speaking with Mr. Thomson about the issue, he told me that I could increase the torque up to 60 in-lbs. I did that and the stem bolts did't get loose.....as fast. They still worked their way loose.

    I'm going to check the steerer again this weekend.

  36. #36
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    Quote Originally Posted by Monte
    I have a Thomson stem that's never come loose. When I tighten it I tighten one side, then the other side, then the other side, then the other side. It seems to take about 4 trips left and right to get it tight. If you are torqueing one side to spec, then torqueing the other side to spec then stopping it will come loose for sure. You need to go side to side 3-4 times.

    Monte
    I've done that. In fact, I've even tried such small increments on each side that it took about 25 alternations......didn't help.

  37. #37
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    I researched stems about two years ago in the reviews section and stayed away from thompson for the very reasons you are describing. I went with the Race Face Dues it has a four bolt removable face and is light and stiff. I use a CK headset and it has never loosened up. It seems that it is a crap shoot with the Thompson stuff.

  38. #38
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    is steerer tube out of round?

    I suggest some testing is in order. I'd try a different stem and/or borrow another fork (or entire bike) to try one of the Th0mson stems on. Marking the bolts would prove useful (as some has suggested) to see if they are twisting.

    I have a feeling that problem has more to to with the steering tube than the stem. I'm guess that the steering tube is a bit out of round, or even flexing.

    Only lightly grease the bolts. Too much grease will ooze into places you don't want it.

    Did you send the first stem back to Th0mson? What did they have to say?
    Last edited by t0land; 06-03-2004 at 07:37 PM. Reason: evil auto-link work around
    Matthew
    God, grant me the courage to sell my car.

  39. #39
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    Correct steerer tube length?

    Is the top edge of the stem 3 mm above the end of the steerer tube? If the distance is less, the top cap can fail to preload the headset properly. If it's more, the clamp doesn't have enough surface to grip. I actually use a torque wrench on both the top cap and the stem. I've used about a dozen Thomson stems without any of them loosening for up to 3 years, most of them on Marzocchi forks, but 3 so far on Fox forx.

    Yes, grease the bolt threads, yes degrease steerer tube and handlebar, yes alternate bolts (takes lots of back-and forth), no Loctite.

  40. #40
    meh....
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    Quote Originally Posted by Blue Shorts
    I've done that. In fact, I've even tried such small increments on each side that it took about 25 alternations......didn't help.
    If you are using a torque wrench just torque it to spec on one side and then do the other and so on until they don't require further turning to come to spec.

    What's the diameter of your steerer tube?

  41. #41
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    Quote Originally Posted by Monte
    If you are using a torque wrench just torque it to spec on one side and then do the other and so on until they don't require further turning to come to spec.

    What's the diameter of your steerer tube?
    I suppose that could work since the opposite side "loosens" as you tighten the other side, but that method seems odd to me. You might end up with the cam pulled lop-sided inside, even if it does end up tight.

    I don't think you should spec torque any multi bolt system one bolt at a time. I think you should alternate bolts until all are tight enough to torque to spec.
    Faster is better, even when it's not.

  42. #42
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    Issue Resolved - Thanks Everyone!!!!!!

    Quote Originally Posted by WarrGuru
    Has anyone here had this problem?

    I've been using a Thomson (Don't buy the stem from Jensen) stem on my 5 Spot for about 1 year. The stem constantly loosens up. I have to tighten the steerer clamp screws before every ride. If I don't, the headset starts creaking after a couple of rides. When I check the screws for torque, they're always looser than spec.

    Thomson asked me to send it to them, but I don't believe that it will help. I went out and bought a new Thomson stem and I have the same issues...What gives?

    The stem is used with a Cane Creek headset and a Marzocchi_ Z1FR (2003) (Don't buy the fork from Jensen) .

    Any help or suggestions would be appreciated. Does anyone have any good stem recommendations? I need a 100 X 5*.
    Well, the issue is now resolved. The fix involed doing 2 things:

    1) reduced gap between top of steerer to top of stem from 5mm to 3mm (Thomson_ spec is 7mm max)

    2) replace mis-matched spacers with new spacers

    I've now gone 74 miles, about 6000 feet of climbing, railroad tracks, small jumps and drops, fast stutter bumps.........the stem is now holding fine. I've got to believe that it was the gap...it was too large. I was within the Thomson_ spec, but maybe the spec is wrong, or my steerer is slightly dimpled and moving the clamp gave it a fresh spot to clamp.

    Either way.....thanks everyone for all of your help!!!!!!!!!!!!!!!!!!!!!!

  43. #43
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    Quote Originally Posted by Blue Shorts
    Well, the issue is now resolved...but maybe the spec is wrong, or my steerer is slightly dimpled and moving the clamp gave it a fresh spot to clamp.
    I'm thinking it was a dimple, or maybe mismached spacers, either way glad you worked it out!

    Cheers
    Faster is better, even when it's not.

  44. #44
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    Quote Originally Posted by Bikezilla
    I'm thinking it was a dimple, or maybe mismached spacers, either way glad you worked it out!

    Cheers
    Me too! Thanks for the stem offer, even though I ended up not needing it.

    Tell me more. What's your theory on the spacers? They were definitely mismatched, but I can't, for the life of me, figure out how the spacers could have contributed to the problem. Can you?

  45. #45
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    Quote Originally Posted by Blue Shorts
    Me too! Thanks for the stem offer, even though I ended up not needing it.

    Tell me more. What's your theory on the spacers? They were definitely mismatched, but I can't, for the life of me, figure out how the spacers could have contributed to the problem. Can you?
    Not with any meaningful logic. Just that if, for example, they didn't sit flush on oneanother or could slip back and forth, that could have allowed some play to rock the stem loose...that's a longshot though. The dimple theory seems the most likely to me, but I've always run the steerer about 2-3mm below the top of the stem clamp. 7mm seems like a helluva lot. I recall at least one of my headset mounting instructions saying use 3mm or less. I'll have to go back and look. I think it was my Cane Creek C2, I don't recall my CK instructions being very different. I gave that priority over the stem instructions, don't ask me why.
    Faster is better, even when it's not.

  46. #46
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    No Loctite?

    [QUOTE=Yes, grease the bolt threads, yes degrease steerer tube and handlebar, yes alternate bolts (takes lots of back-and forth), no Loctite.[/QUOTE]

    I see a lot of posts in this thread saying no loctite. What's the reasoning?
    The stem on my spot was coming loose on every ride. King headset, Z1 FR and
    some kind of specialized stem. I used blue loctite on the bolts
    and have had no problems for several months.

  47. #47
    Brass Nipples!
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    Loctite

    Thomson instructions call for just grease on the bolts, and that's always worked fine for me. Loctite is useful for lots of things, especially if a part is assembled according to instructions and still comes loose.

    I always use Loctite for cleat screws on shoes and the self-extracting bolt covers in the center of previous generation XTR cranks, as I've had them come loose before. Mavic UST rims need Loctite on the rim inserts that hold the nipples in place.

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