Why using this small spacer on the top of the stem (Team Emirates)?

Discuss light weight issues concerning road bikes & parts.
TobinHatesYou
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by TobinHatesYou

TonyM wrote:
Sun May 13, 2018 2:48 pm
Would it still be safe not to use this small spacer on the top of the stem?

Especially in the particular case of a C60 fork with the Deda superleggera stem? And I am not a sprinter.
It depends on the design of the stem. For example my Bontrager XXX integrated bar/stem has the bolts closer to the middle of the clamp. Also the top of the clamp is a slightly bigger diameter so it actually doesn't contact the top of the steerer. It was designed to be used without a 5mm spacer on top if desired.

If you only partially clamp the steerer with most stems, you are significantly reducing the contact area and increasing the necessary pressure to secure the stem. Remember that most steerer clamps are hollow on the front side...You run the risk of delaminating the steerer, especially at the top where the cut fibers are.

Zakalwe
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by Zakalwe

Calnago wrote:
Sun May 13, 2018 4:36 pm
It can’t compress or “cone” the top of the steertube. Even if the lip is ever so slightly smaller (it is by a very small bit) it’s not plastic and still very supportive
I get that, but personally I want the entire length of the stem to be clamping on something rather than only 90% of the steerer. 5mm spacers don’t bother me, so I left the steerer about a mil longer and drop a spacer on top, happy days.

by Weenie


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Calnago
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by Calnago

@Zakalwe: Agreed! Every one of my bikes is set up exactly that way. Enough steertube (or compression plug lip) extending above the stem to provide a lip for a 5mm spacer to set upon and provide an ample gap to provide preload without bottoming out on the compression cap itself. So I’m with you on that personally. But there are quite a few systems that actually are intended and designed with a flush top cap in mind. Colnago’s current top cap is very thin and can sit flush with the steertube only 2mm below. But even still, while I’ve seen lots set up that way, I too prefer full and complete contact and opt for the added assurance of the 5mm spacer approach. Just seems right.
@TonyM: Given that you’re talking about a light stem with a shorter than average stack height, I would err on the side of safety and use the 5mm spacer and get complete contact between stem and steertube. I’ve always been an advocate for that in the past but given how some designs are these days, you really have to look at each scenario case by case and use sound judgement. And in your case, so long as you are using the compression plug that came with your C60, a spacer above the stem will not compromise the most critical area that Deda wants supported, the lower lip of the stem. Yesterday I cut a couple millimeters from my steertube so I could use the new Pro Vibe stem. But I’m using my own top cap which meant I had to purchase a special spacer kit just to get their very proprietary spacer for the top of the stem in cases where you don’t want to use theirs, which requires that the top of the steertube (including any lip from a compression plug), to be 2mm below the top of the stem collar.
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TonyM
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by TonyM

Calnago wrote: @TonyM: Given that you’re talking about a light stem with a shorter than average stack height, I would err on the side of safety and use the 5mm spacer and get complete contact between stem and steertube. I’ve always been an advocate for that in the past but given how some designs are these days, you really have to look at each scenario case by case and use sound judgement. And in your case, so long as you are using the compression plug that came with your C60, a spacer above the stem will not compromise the most critical area that Deda wants supported, the lower lip of the stem. Yesterday I cut a couple millimeters from my steertube so I could use the new Pro Vibe stem. But I’m using my own top cap which meant I had to purchase a special spacer kit just to get their very proprietary spacer for the top of the stem in cases where you don’t want to use theirs, which requires that the top of the steertube (including any lip from a compression plug), to be 2mm below the top of the stem collar.
Thanks for the feedback.
Yes I decided to go safe and have a full contact of the compression plug with the steerer and therefore keep the small spacer on top of the Deda Superleggera stem. Like the Team Emirates.

pdlpsher1
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by pdlpsher1

I use a 2.5mm spacer on the top. This does require the steerer to be cut flush to the top of the stem. For me it’s good enough safety wise and it looks better than a 5mm spacer.


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Calnago
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by Calnago

No, a 5mm spacer looks best.
Plus, if it’s actually flush, there’s no lip for the spacer (whatever size) to fit nicely upon.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
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guyc
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by guyc

Flush looks best!

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Calnago
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by Calnago

Whoops... someone cut his steertube too short. :). It’s fine. Whatever you like, as long as you’re covering that top stem bolt span.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
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guyc
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by guyc

Ha no. It’s getting cut down a little more on Weds but it’s all good anyway. My shop does it. I just like the look of flush.

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Calnago
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by Calnago

You only had a 10mm spacer under the stem. Gonna slam it? Maker sure they end up with no more than 2mm of a gap between the top of the stem and the steertube. What stem are you using again? Is it a standard 40mm stack height?
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
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TonyM
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by TonyM

guyc wrote:Flush looks best!
+1

Yepp look best IMHO also.

Too bad that it seems that it is safer to have a small spacer on top of the stem Image

guyc
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by guyc

Calnago wrote:
Mon May 14, 2018 6:47 pm
You only had a 10mm spacer under the stem. Gonna slam it? Maker sure they end up with no more than 2mm of a gap between the top of the stem and the steertube. What stem are you using again? Is it a standard 40mm stack height?
I am. I’ve been running with one 5mm above and one below for the last fortnight and want it a little lower. Still running the higher top cap anyway.

I will. They do a lot of Colnagos so should be all good. It’s a 3T Arx Ltd so 40mm yes.

Zakalwe
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by Zakalwe

I’ve got a slammed 73d stem on my C60 with a 5mm spacer on top. I think that looks best, personally

Oh, and my Ritchey stem has a lower stack height that normal.

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Calnago
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by Calnago

TonyM wrote:
Mon May 14, 2018 6:53 pm
guyc wrote:Flush looks best!
+1

Yepp look best IMHO also.

Too bad that it seems that it is safer to have a small spacer on top of the stem Image
Especially with the Superlegerra stem you want to use... short stack height and top bolt being quite close to the very top of the stem it seems. I'd use a spacer in that circumstance for sure.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

by Weenie


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Calnago
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by Calnago

Zakalwe wrote:
Mon May 14, 2018 7:21 pm
I’ve got a slammed 73d stem on my C60 with a 5mm spacer on top. I think that looks best, personally

Oh, and my Ritchey stem has a lower stack height that normal.
Got any pics of your setup anywhere, whole bike etc? Not sure I've seen it if you have. Just curious. Post it in the Pics of Colnagos thread if it isn't there already.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

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