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Tiny gap between spacer & -17 stem because geometry?

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Tiny gap between spacer & -17 stem because geometry?

Old 05-30-22, 08:28 AM
  #1  
the sci guy 
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Tiny gap between spacer & -17 stem because geometry?

Is this normal/ok? Slid my -17° stem onto the steerer and because of the angle it doesn’t fully clear the spacer width so it kind sits slightly off kilter and there’s a small gap where you can see the steerer.
Will this cause bad wear/tear on the stem or mess with anything? Is it because it’s only an 80mm stem and if it were longer it might clear?


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Old 05-30-22, 09:05 AM
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Was the frame faced when headset install? I always have a pro install headset, because I don't have the tools to check the frame. I think your headset is crooked.
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Old 05-30-22, 09:16 AM
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It is hard to tell from the photo provided. That Zipp stem has rounded contours whereas the spacers are squared off. The angle on the stem looks like it is beyond horizontal making it look like a track stem. Bike shops may have a stem facing tool where they can freshen up the mating surface.
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Old 05-30-22, 09:20 AM
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God I love my quill stem…
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Old 05-30-22, 11:19 AM
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Originally Posted by masi61 View Post
It is hard to tell from the photo provided. That Zipp stem has rounded contours whereas the spacers are squared off. The angle on the stem looks like it is beyond horizontal making it look like a track stem. Bike shops may have a stem facing tool where they can freshen up the mating surface.
it’s a +/- 17° stem which when you flip it over makes the stem pretty parallel to the ground - depending on your headtube angle. It’s not as drastic as a track stem.
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Old 05-30-22, 12:12 PM
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If you flip the stem from how you have it in the picture, it will be not almost parallel to the ground. It will be rising 17 degrees in relation to the head tube. With it oriented like you have it in the picture, that is the closest it will be to parallel on that bike. I am not an expert, by far, and not sure from the picture, but it does look like the head set cup could be set crooked. Look at the interface between the top cap and the spacer below it. Does it look like the top cap is centered and square on with that spacer? Depending on the shape of the underside of the cap, if it is not, it could interfere with the stem seating correctly when the cap is torqued.
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Old 05-30-22, 09:53 PM
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It may or may not be an issue. If the head tube ends are not parallel to each other, (and perpendicular to the head tube), and the steerer is not centered, it will probably cause more stress on the bearings at a particular point since any impact will not be absorbed evenly over the headset bearings. How this effects longevity, in miles, is hard to say.

It may also impact how smooth the handlebars turn through the entire arc.

If it is a spacer issue and you are able to pre-load the bearings so they are smooth with no play, it probably has no impact once the stem is tightened to the steerer tube.

John
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Old 05-30-22, 10:55 PM
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Take the stem off and examine the mating surface. It should have been machined flat where it meets the spacers.
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Old 05-31-22, 03:10 AM
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Originally Posted by the sci guy View Post
Slid my -17° stem onto the steerer and because of the angle it doesn’t fully clear the spacer width so it kind sits slightly off kilter and there’s a small gap where you can see the steerer.
Are you saying that the steep downward angle of your stem causes the stem to ride up from the spacer below the stem at the front of the steerer? Somehow that does not seem too likely.

Originally Posted by the sci guy View Post
Is it because it’s only an 80mm stem and if it were longer it might clear?
No. Stem angle and length do not affect each other.
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Old 05-31-22, 04:19 AM
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After checking to make sure the headset was installed square, I'd bevel the spacer and call it good.
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Old 05-31-22, 04:29 AM
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That looks like a knock off stem that was not properly faced to make the mating surface flat.
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Old 05-31-22, 08:20 AM
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Originally Posted by dsaul View Post
That looks like a knock off stem that was not properly faced to make the mating surface flat.
Good point. Here's some photos from the SRAM/ZIPP site of the current model. The Zipp logo is larger and there is a sharper bevel at the steerer clamp area groove and slightly extended tapered area on the top and bottom clamp in the photos. The OP's stem is shorter and could account for using a smaller Zipp label and graphics come in different versions over the years from what I've seen. It could also be an older version stem that doesn't look exactly the same at the steerer clamp or just distortion from the photos but maybe worth contacting SRAM about. Service Course SL Stem | ST-SC-SL-B2 | Zipp (sram.com)

Last edited by Crankycrank; 05-31-22 at 08:25 AM.
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Old 05-31-22, 09:21 AM
  #13  
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Originally Posted by Crankycrank View Post
Good point. Here's some photos from the SRAM/ZIPP site of the current model. The Zipp logo is larger and there is a sharper bevel at the steerer clamp area groove and slightly extended tapered area on the top and bottom clamp in the photos. The OP's stem is shorter and could account for using a smaller Zipp label and graphics come in different versions over the years from what I've seen. It could also be an older version stem that doesn't look exactly the same at the steerer clamp or just distortion from the photos but maybe worth contacting SRAM about. Service Course SL Stem | ST-SC-SL-B2 | Zipp (sram.com)
As far as I know it’s a legit stem. It came from a bike shop and came in normal Zipp packaging:




The stem on the website you linked to is showing the +/- 6° stem, so the angle is much less than the +/- 17° stem I ordered.
And the logos are slightly different due to its shorter length (80mm) than what’s usually shown on websites (100mm or more most likely.)

I ordered a cheap headset press that should arrive today and I’ll double check making sure the cups are in and straight. I will also try a different spacer though pretty sure it won’t matter because they all came in the same package.

Stay tuned?
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Old 05-31-22, 09:32 PM
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Update:

got the tool today and pressed the headset cups more snugly and straight - as far as I could tell. So I’m happy about that.

The spacers are a bit thick I guess their circumference is a little more. Than the stem steerer clamp area.

The kicker is, once I got the stem on there after putting on a different spacer, the gap looked closed on the right side. But still persisted on the left side (same as first pic in first post)

Looks good? (Zoom in )


and the left side (zoom in to see gap)





so now my question becomes why is it showing on one side and not the other? Is the internal facing of the stem uneven? Is the headset uneven? Is the…?
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Old 05-31-22, 09:34 PM
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Oh and the angle of the stem still barely clears the upper edge of the spacer. The metal black spacer I had before, the stem was still laying on it so it raised it a mm or so like in my first post.
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Old 06-01-22, 04:51 AM
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Certainly looks like the stem isn’t properly faced. I would take it back to the shop where you bought it, ideally still on the bike, so they can get eyes on the problem.
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