Carbon steerer tube cutting

[fraz101]

I plan on cutting my carbon steerer tube on my giant tcr pro.

I have read some conflicting advice on what to do. Here are the opinions.

1) if I want to remove 20mm of spacers I cut 20mm of tube PLUS 3mm extra for the expander plug which will sit on top.

2) If I want to remove remove 20mm of spacers , simply cut 20mm off the steerer as the extra 3mm will already have been accounted for on the initial set up.

3) if I want to remove 20mm of spacers I should remove 15mm of tube and fit a 5mm spacer above the tube before I tighten the top cap.

Opinions please!

 

[fossyant]

Assuming you have the bike and want to remove a 20mm spacer, you cut off 20mm - you do already have a gap for the top cap ?

The extra 3mm is for a new fork, not one that's fitted. Measure twice though !

 

[Venod]

I always go for a 5mm spacer especially with a carbon steerer, it ensures the whole of the stem is clamping on the steerer, but having said that if it wasn't possible I would be happy with a 3mm unclamped gap.

 

[Sharky]

Cut it so that you still have at least one spacer above the stem when you've refitted it. This will allow tweaking in the future to raise the bars a bit.

 

[biggs682]

Why cut it ?
The next owner might be grateful of the extra 30mm and so might you in a couple of weeks, I know I would 😜

 

[ColinJ]

You can use up some of any extra space above the stem with a steerer Garmin mount like this.

 

[cyberknight]

You can use up some of any extra space above the stem with a steerer Garmin mount like this.

Looks interesting I could do with them

 

[cyberknight]

Why cut it ?
The next owner might be grateful of the extra 30mm and so might you in a couple of weeks, I know I would 😜

My thoughts too I would only cut a steerer if I knew I was going to Keep it for a long time and allow a bit just in case .in the last 10 years I have shortened my stem by 10 mm and raised by 5 mm.
Of course if you want to cut it go ahead and if your not sure get a lbs to do it

 

[wafter]

I'm with @biggs682 on this one; not only does cutting it irreversibly alter it potentially to the detriment of future saleability, CFRP's not an easy material to work with and cutting it risks delamination. Finally, given the perculiarities of composite there's a strong argument for keeping a number of spacers on top of the stem so that the clamp is positioned further down the steerer tube; reducing the stresses at the end of the tube and again reducing the predisposition to failure.

There's a good leuscher Teknic (sp) video on youtube about stem selection for CFRP steerers that touches on this, if you fancy a look

 

[Venod]

CFRP's not an easy material to work with and cutting it risks delamination.

I would recommend a fine tooth hacksaw blade or cutting disc to avoid delamination, I have cut carbon steerers with both with no problems, also a cutting guide is useful to get a straight cut, I think you can buy such a guide, but two jubilee clips work well.

 

[Jameshow]

Assuming you have the bike and want to remove a 20mm spacer, you cut off 20mm - you do already have a gap for the top cap ?

The extra 3mm is for a new fork, not one that's fitted. Measure twice though !

Ten times on different days!!

 

[sevenfourate]

I would recommend a fine tooth hacksaw blade or cutting disc to avoid delamination, I have cut carbon steerers with both with no problems, also a cutting guide is useful to get a straight cut, I think you can buy such a guide, but two jubilee clips work well.

^^^Good advice. Wrapping the area in (Masking ) tape; can also help alleviate problems associated with the cutting of Carbon Fibre. ****I’ve been building + hence cutting golf clubs using Carbon / Boron / Graphite shafts for 30+ years……

 

[wafter]

I would recommend a fine tooth hacksaw blade or cutting disc to avoid delamination, I have cut carbon steerers with both with no problems, also a cutting guide is useful to get a straight cut, I think you can get buy such a guide, but two jubilee clips work well.

Indeed, I think ideally something like a chop-saw with an abrasive disk rather than something with actual teeth.. or if it is then fine ones as you suggest. Think I'd probably be inclined to use a rotary tool with slitting disk, although one would have to be careful to avoid heat buildup or the epoxy clogging the disk; while an even cut would probably be difficult if using a small disk that has to be run around the steerer's circumference.

Again, all good reasons to leave it alone IMO!