Trek is pretty picky about stem design to prevent steering tube damage - they want no open holes on the backside of the stem clamp, clamping bolts spread out and no large holes on the inside of the clamp where it joins to the horizontal tube. Just had my fit redone and I need a 130mm stem, but there isn't a Bontrager 130mm RXL that I can see, they stop at 120 and I don't really want a carbon stem. Any suggestions on a stem that meets the Trek recommendations for stems? The only thing I could find is maybe the new Zipp Service Course SL stem, but I can't see how big the hole is on the inside of the steering tube clamp in any online pictures.
130mm stem for Domane
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Trek is pretty picky about stem design to prevent steering tube damage - they want no open holes on the backside of the stem clamp, clamping bolts spread out and no large holes on the inside of the clamp where it joins to the horizontal tube. Just had my fit redone and I need a 130mm stem, but there isn't a Bontrager 130mm RXL that I can see, they stop at 120 and I don't really want a carbon stem. Any suggestions on a stem that meets the Trek recommendations for stems? The only thing I could find is maybe the new Zipp Service Course SL stem, but I can't see how big the hole is on the inside of the steering tube clamp in any online pictures.
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I wasn't sure if I understood so goolged pictures of Bontrager RXL to get an idea of what you were looking for then took a look at Domanes on Treks web site and it doesn't appear they are following their own advice on all the Domane models.
I think you're safe ignoring those requirements. A carbon steering tube is a carbon steering tube (they're all carbon and all round) so if a stem is good enough for any bike brand, which 99% if them are, it's good enough for a trek.
I think you're safe ignoring those requirements. A carbon steering tube is a carbon steering tube (they're all carbon and all round) so if a stem is good enough for any bike brand, which 99% if them are, it's good enough for a trek.
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Show me where that is printed and I'll believe it.
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I can believe that Trek believes it.
For a while they and many other bike companies would void your carbon frame warranty if you used the frameset in a stationary trainer.
About five years ago, Trek did send out two tech bulletins on incompatible stems for carbon steerers after some steerer failures during races. Can't find either bulletin on the web, but they are cited or summarized on many sites.
From a description of the second bulletin, quote:
"The issues with other stems has to do with placement of cutouts, size of lightness holes, and even angle of the clamp bolts. Proper stems should have no clamp cutaways like pictures on the FSA stem to the left, as according to Trek’s engineers, the cutaways can allow the separate parts of the stem to dig into the steerer.
Also, the lightening hole inside the steerer tube clamp must adhere to a sizing guideline. The hole must have at least 10 mm of stem material between the edge of the hole and either lip of the stem. A lightening hole that is too large can allow the edges to gouge the steerer tube as the bars are muscled around.
The issues with other stems has to do with placement of cutouts, size of lightness holes, and even angle of the clamp bolts. Proper stems should have no clamp cutaways like pictures on the FSA stem to the left, as according to Trek’s engineers, the cutaways can allow the separate parts of the stem to dig into the steerer."
Another issue according to Trek is edge treatment. Sharp edges around cutouts, holes and at the ends of the clamp could dig into the steerer carbon. The recommendation, of course, is "use only stems the Trek bike came with," which (for me, anyway) threw some doubt on all these dire warnings from Trek.
Source of italic quote above: Broken Trek Carbon Steerer Tubes: Result of the Wrong Stems?
From a description of the second bulletin, quote:
"The issues with other stems has to do with placement of cutouts, size of lightness holes, and even angle of the clamp bolts. Proper stems should have no clamp cutaways like pictures on the FSA stem to the left, as according to Trek’s engineers, the cutaways can allow the separate parts of the stem to dig into the steerer.
Also, the lightening hole inside the steerer tube clamp must adhere to a sizing guideline. The hole must have at least 10 mm of stem material between the edge of the hole and either lip of the stem. A lightening hole that is too large can allow the edges to gouge the steerer tube as the bars are muscled around.
The issues with other stems has to do with placement of cutouts, size of lightness holes, and even angle of the clamp bolts. Proper stems should have no clamp cutaways like pictures on the FSA stem to the left, as according to Trek’s engineers, the cutaways can allow the separate parts of the stem to dig into the steerer."
Another issue according to Trek is edge treatment. Sharp edges around cutouts, holes and at the ends of the clamp could dig into the steerer carbon. The recommendation, of course, is "use only stems the Trek bike came with," which (for me, anyway) threw some doubt on all these dire warnings from Trek.
Source of italic quote above: Broken Trek Carbon Steerer Tubes: Result of the Wrong Stems?
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and I fail to see the difference between edges of a cut away and edges at the top and bottom and back where the things tightens or loosens. Edges are unavoidable so if edges are a problem for reasons other than deformity they are essentially saying you can't use a stem on their forks.
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Thanks, for a minute after reading some responses I thought I perhaps was imagining it - but that's information I was referring to. Maybe it's dated and/or the issue was a not related to the stems to start with. Looking at my current Bontrager stems, they all seem to follow the guidance mentioned above though. Hard to imagine why there would be a difference in carbon steering tube design enough so that there would be a special requirement for one manufacturer. Maybe I'm over thinking it.
It's about the edge treatment after the forging or machining. According to Trek, some companies don't clean the edges up enough (de-burr, chamfer, round off and polish).
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Here's a service bulletin - http://www.bike-manual.com/brands/trek/om/assets/pdfs/10bt_ca_steerer_stem_0701PN.pdf
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Just gets new bars with a reach difference to use with the existing stem to the desired reach result.? Excuse to get those chi chi carbon bars... ???
I have an OVAL stem with the canted slot on my Six 13, and that angle stress makes a lot of sense to me the @ 90^ frankly..
I have an OVAL stem with the canted slot on my Six 13, and that angle stress makes a lot of sense to me the @ 90^ frankly..
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Not according to the bulletin you quoted though which clearly refers to cut outs ect. not the machining of cut outs. But regardless bad forging and machining is certainly a legit. thing to avoid with any fork but with 99.9% of stems (probably not literally but you get the point) working fine with other carbon forks there's not much need for concern here, certainly no need for a concern unique to having a trek and buying a Bontrager stem or identical design isn't the only solution.
Sorry, some misunderstanding here. I thought you were talking about my "sharp edges" paragraph ("Another issue......" last para.)
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okay. No biggie. Based on your comment that I pasted below I'm pretty sure we see this the same way despite the apparent temporary disagreement.
"The recommendation, of course, is "use only stems the Trek bike came with," which (for me, anyway) threw some doubt on all these dire warnings from Trek."
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Those are great. Before using one I always thought people who talked about stem flex were full of crap because stem choice didn't matter......but I noticed right away when I replaced a stock cannondale stem with one of those that it felt much better (stiffer, more secure feeling) when sprinting and climbing standing up.
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Good to hear Jay, the little research I did gave these top notch reviews so was hoping for the best - Always good to hear from someone with personal experience outside of a formal review!
For what it's worth, I just measured the inside of a Ritchey stem I had on my desk. That specified dimension for the area above and below the hole is only 8mm vs. the 10mm Trek specifies in those bulletins posted.
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I put the stem on the Niner this morning - and did a 30 mile ride - it sure does feel stiff - I was surprised at the difference!
The one I received had 8mm below with it flipped down, and 10mm above flipped up, so it's pretty close but not as Trek specifies. Interesting how that hole and machining can vary from one stem to the next.
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