trimming steer tub advice for not over trimming

[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]

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.

[digitalnorbs]

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

[5 8 5]

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

[BobSantini]

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'?

[allezkmiec]

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

[NiFTY]

Cannondale recommends cutting 2mm below the top of the stem

[NWSAlpine]

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]

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]

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

[Mikmik]

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.

[5 8 5]

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

[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.

[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]

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.