Colnago C60 fork: are spacer under/ above the stem necessary?

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TonyM
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Joined: Thu Jan 22, 2015 4:11 pm

by TonyM

Hi,

I currently have 2 spacers under my stem on my C60 and no spacer above my stem and I am considering removing these 2 spacers as the position is too "upright".

I read somewhere that depending on the manufacturer you have to keep some spacers under and/ or above the stem.

What does Colnago recommend for the C60?

Can I get rid of all spacers under and above the stem or do I have to keep some?
Last edited by TonyM on Mon May 22, 2017 7:46 am, edited 1 time in total.

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Zakalwe
Posts: 786
Joined: Sun Jun 17, 2012 3:15 pm

by Zakalwe

You don't necessarily need any below the stem, whether you need any above it depends on your stem clamp more than the steerer tube. The C60 comes with two difference risers, one more cone shaped and the other as flat as is practical. You can drop the stem straight into either of those, it's the same preload on the bearings either way.

Personally I always keep 5-10mm above the stem, I'm only going to get older in this life.

moonoi
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Joined: Sat Nov 21, 2015 3:04 pm
Location: Earth

by moonoi

I think you're referring to Trek, who with Bontrager Aluminium stems require that you have a minimum of 5mm below and 5 mm above the stem. This isn't a requirement with a carbon stem.

I don't believe there is such a requirement with the C60, and don't see it mentioned in the manual that came with mine, so you should be fine without.


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Calnago
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by Calnago

Trek says at least a 5mm spacer under the stem and above. That was a result of some snapping steertubes back in the day (carbon, not aluminum). It would lessen the chance of a stress riser at the lower edge of the stem where it meets the fork. The spacer above the stem is just to ensure full contact between the stem and steertube and prevents "coning" the top of the steertube in the case where the top of the steertube is too close to where the top stem clamps. They even had a warning NOT to use FSA stems.
However, that was then, and I've seen Treks with no spacers under the stem, FSA stems etc. It's not hard to find pics of their pro bikes going against these recommendations.
Colnago doesn't have any "recommendations" in that regard, but I do like to use a 5mm spacer above the stem as kind of my "best practice" routine. It allows for full contact between the stem and steertube and provides enough of a gap between the top cap and the expansion bolt to allow for a preload without bottoming out. Also I just like the way it looks with a 5mm spacer above. You don't "have to" however, just make sure if you're going to go with a "flush with the top of the stem" look to make sure the top of steerer is above the clamping forces of the upper stem bolt. And if you use the supplied long expansion plug that comes with the C60, it will extend all through the stem and well past lower bearing providing a lot of extra structural strength. Like was mentioned, your C60 with the Acros headset should have come with two top caps, a very short one and a taller one, so by using the short one you can get it pretty slammed if you have to.
So, to the OP, you are fine to remove the spacers on your C60.
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