Cutting a carbon steerer

[ishaw]

I need to trim a new rockshox carbon steerer. Its a new old stock sid works cup, so I don't want to make a mess of it, nor do I want to cut it too short if I decide to move it on to another frame in future.

What's the best way to cut it?

How much extra would you leave on it, just in case?

I don't mind running spacers above the stem as long as it doesn't look too fugly.

 

[Woz]

I've used a hacksaw with a deliberately blunt blade to cut carbon steerers without issue.

 

[spacehopper]

Re:

ive used the park carbon saw blade to great success.. (on handlebars)

plenty of water on the area whilst cutting to contain the dust.. a dust mask.. and something underneath that can be chucked straight in the bin to catch the dust.. (carbon dust is evil stuff!) nice long gentle strokes.. it cuts much easier than metal..

i turn the bars and cut all the way round now.. if you go straight through.. you can be left with a really uneven cut at the end where the tube essentially just breaks and falls off.. that being said.. its really easy to file it straight afterwards.. but remember to contain the dust somehow!

the spacers above the stem thing is just to ensure the stem is 100% in contact with the steerer to help spread the load.. cut it just right and you could get away with just a 1/2mm spacer above the stem if your topcap allows it..

 

[ishaw]

Re:

Thanks so far. About the steerer length, as mentioned I want yo leave enough to allow flexibility if I want to move to other frames with different head tube lengths. How to determine this is my challenge. Leaving extra with spacers above the steerer, how much is too much/aesthetically ugly?

 

[Woz]

Re: Re:

Thanks so far. About the steerer length, as mentioned I want yo leave enough to allow flexibility if I want to move to other frames with different head tube lengths. How to determine this is my challenge. Leaving extra with spacers above the steerer, how much is too much/aesthetically ugly?

...it's everyone's challenge.

I would say one 5mm spacer above the stem is acceptable, anything more, it's ugly.

You can play around with stems that have a high stack height vs. a low stack height too so you don't cut the steerer
too short. Kore and early Easton for example have a high stack height.

 

[ishaw]

Re:

stem will be a Thompson for current build. Future, no idea.

 

[Yogi bear]

Re:

https://m.youtube.com/watch?v=EWzN6GZeEzs

Proper technique.

 

[danson67]

On carbon, I alwasy use a tungsten carbide grit hacksaw blade, light abrasive 200 grit paper to get rid of any snaggy bits (technical term ), and then seal the cut end with clear varnish to prevent water ingress into the open fibre ends.

All the best,

 

[Madmax1993]

Re:

As above, but I also tape up the steerer where I cut just in case the carbon weave tries to unravel. Then once it's done remove the tape bandage and admire the smooth clean cut.

 

[66 triumph daytona]

Re:

Put some tape over the cut and use a fine tooth junior hacksaw.One thing to keep in mind is carbon fibre dust is lethal so wear a dust mask and disposable gloves and try to cut over a bin so none of the stuff remains on the floor.