trimming steer tub advice for not over trimming

Discuss light weight issues concerning road bikes & parts.
digitalnorbs
Posts: 488
Joined: Mon Jul 31, 2006 6:49 pm

by digitalnorbs

so I just got a new frame, Cervelo RS and I want to make sure that I dont trim it to much, but do want to leave enough in case I want to come up higher. So do I measure from the headset carbon cone or from the top of the headset. How much do I allow for the spacers, stem, and maybe one small spacer on top. please adive

daj
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Joined: Mon Oct 12, 2009 6:36 pm

by daj

Assemble the bike without cutting the steerer. Then installed the maximum amount of spacers you think you would need and install the stem. Add 2 mm and cut it there.

by Weenie


digitalnorbs
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Joined: Mon Jul 31, 2006 6:49 pm

by digitalnorbs

is there a max spacers that can be put below the stem?

5 8 5
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Location: UK

by 5 8 5

Manufacturer specific. Check the docs that came with your frame.

BobSantini
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by BobSantini

daj wrote:Assemble the bike without cutting the steerer. Then installed the maximum amount of spacers you think you would need and install the stem. Add 2 mm and cut it there.


Shouldn't that be 'subtract 2 mm'?
r o y g b i v

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allezkmiec
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by allezkmiec

Adding 2mm will allow for a 5mm spacer above the stem, which is generally good practice with any carbon-steerer fork.

NiFTY
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by NiFTY

Cannondale recommends cutting 2mm below the top of the stem
Evo 5.02kg SL3 6.77 Slice RS 8.89 viewtopic.php?f=10&t=110579" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

NWSAlpine
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Location: FL

by NWSAlpine

allezkmiec wrote:Adding 2mm will allow for a 5mm spacer above the stem, which is generally good practice with any carbon-steerer fork.


If it's carbon steerer and using an expander plug then below the stem is usually recommended. You can add a 5mm above but you have to make sure you install the expander plug deep enough.


Although he has a Cervelo RS and there are instructions here http://www.cervelo.com/r/3T%20Fork_instruction.pdf It involves more than normal.

digitalnorbs
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Joined: Mon Jul 31, 2006 6:49 pm

by digitalnorbs

thanks, but I was wondering if there is a limit of how high the stem can be. I been hearing that you can go up from the cone for another 4-5 cm, then stem, then 2-5mm on top. doest that sound right

xnavalav8r
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by xnavalav8r

If you're going to add 4 or 5 cm of spacers, you're on the wrong frame.

Mikmik
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Joined: Tue Sep 28, 2010 10:30 pm

by Mikmik

NiFTY wrote:Cannondale recommends cutting 2mm below the top of the stem


Are you absolutely sure?!?! Cutting 'below' the stem height reduces the effectiveness of the top bolt on the stem as it is not gripping onto the steerer enough. I VERY highly doubt your info is correct.
It's not how much you spend on a bike it's how hard you can ride it.

5 8 5
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by 5 8 5

NiFTY is correct. Cannondale specify not to put a spacer above the stem.

Mikmik
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Joined: Tue Sep 28, 2010 10:30 pm

by Mikmik

That is very surprising to say the least!!

My steerer was cut about 2 or 3 mm lower than the stem and the top of the stem (at the top bolt tabs) closes in when tightening. This does not apply as much grip pressure on the steerer compared to having the steerer protrude past the stem. It reduces the effectiveness of the top bolt and this may not have any negative consequence to your general riding/training/racing but in a max-effort-sprint out of the saddle it would be a little un-nerving.
It's not how much you spend on a bike it's how hard you can ride it.

digitalnorbs
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Joined: Mon Jul 31, 2006 6:49 pm

by digitalnorbs

I'm sorry if not wording my self correctly, I'm for sure going to have few mm of steer tube past the stem. I I was just wondering what is the limit of steer tube that I can have before it gets to the stem

Mikmik
Posts: 313
Joined: Tue Sep 28, 2010 10:30 pm

by Mikmik

As long as you have even a thin shim (mine is less than a 1mm aluminium shim) between is fine. It's generally accepted that putting stem straight on top is not advisable.
It's not how much you spend on a bike it's how hard you can ride it.

by Weenie


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