Cutting a carbon steerer

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dennetti

Active Member
Location
Bristol
Hi. I am building up a new bike and need to cut the steered. Not sure where to cut it, and am concerned I'll cut it too short. Can anyone suggest where I should cut it. I am early fifties but fit, so don't want too extreme angle, but am looking for fairly low front end. Is there a rule of thumb, or perhaps a middle of the road setting I should aim for. It's a Planet x ec130.
Thanks for any advice.
 

I like Skol

A Minging Manc...
Leave it long to start with and use lots of spacers. Move the spacers a bit at a time to vary the stem height with different amount of spacers above and below the stem clamp until you are happy with the position during test rides.
Then, and only then, you can make the final cut to the steerer. You could still leave a small stub above the stem just in case. IMO a 10mm spacer above doesn't look bad and leaves you a little wriggle room if you find you have gone too low.
 
U

User6179

Guest
If you dont want a 10mm spacer at the top, just set the height with the stem flipped down then you always have the option of flipping it up.
 

I like Skol

A Minging Manc...
You could start off with 40-50mm of spacers below stem, then gradually over a couple of weeks of rides drop the stem 5-10mm at a time, adding the removed spacers above the stem so you don't have to cut each time and always have the option to go back to the highest position if you find this suits you best.
 

greenmark

Guru
Location
Geneva
You could start off with 40-50mm of spacers below stem, then gradually over a couple of weeks of rides drop the stem 5-10mm at a time, adding the removed spacers above the stem so you don't have to cut each time and always have the option to go back to the highest position if you find this suits you best.

As you gradually move the stem down, be careful not ever to leave too many spacers above where you clamp the stem.
If you over-tighten the stem then you can crush a carbon steerer. This can be avoided if the stem clamps around the expander plug. If you have too many spacers above the steerer then your stem will be below the plug. You can safely get away with up to 20mm in spacers above.
 

Milkfloat

An Peanut
Location
Midlands
One last bit of advice. When you do make the cut, you need to make sure that cut is slightly below the level where the top spacer will be. Otherwise you won’t be able to preload the headset.

This photo is not perfect as it does not show a spacer on top of the stem , but this is the sort of gap you need between the top of the steerer and the top of the spacer.

808168d1371235975-uncertainty-regarding-stem-installation-fork11.jpg
 

Hugh Manatee

Veteran
Also, do not get anywhere near to the dust. I am a member of a knife making forum and carbon scale (handle) posts never happen without a mention of wearing the best ppe dust filter you can find.
 
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dennetti

dennetti

Active Member
Location
Bristol
Thanks. I've taken all that on board. Much appreciate your advice. Just buying all the parts and tools need, so will get busy with this in the next couple of weeks. If you see my new ec130 forks for sale on the forum, you'll know it hasn't gone well!
 

Tommy2

Über Member
Location
Harrogate
IMG_1265.JPG
Measure twice cut once.... that is my advise, and don't rush into it, you can always take more off but can't put more back on.... you can probably guess why I advise this :sad:

So when you've found your position, put any lower spacers on, then the stem, then cut 5mm above the top of the stem so when you put a 10mm spacer on top the steerer tube will be 5mm below the spacer allowing for pre loading the headset.

It's advisable to put a spacer above the stem so that the stem is clamping round a complete steerer unlike the picture of the stem a couple of posts above (although that picture is not a carbon steerer so may not be applicable).

If you need to borrow this tool, let me know.

If I'm incorrect with anything I've said someone please correct me.
 
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dennetti

dennetti

Active Member
Location
Bristol
On a related subject, what sort of top cap and bolt do you recommend. Would normal star type do the job, or are there other solutions which might be better for he planet x ec130?
 
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dennetti

dennetti

Active Member
Location
Bristol
Thanks a lot. That's good advice. I'd like to borrow the tool if you don't mind. I have been trying to buy the x tools version of this tool but seems to be sold out everywhere.
 

Tommy2

Über Member
Location
Harrogate
Thanks a lot. That's good advice. I'd like to borrow the tool if you don't mind. I have been trying to buy the x tools version of this tool but seems to be sold out everywhere.
Pm me your address when you want to borrow and I'll post it out.
 
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