Trimming/Sanding Carbon Steerer

dannbodge

A while ago I moved my handlebars to be a lot lower than standard.
My LBS cut down the steerer tub to accommodate the new height + 5mm spacer.

Since then it was making creaking noises, so I let them check it out.
They came back with "the steerer is too long, so we've changed the 5mm spacer for a 10mm to get the correct pre-load)

They've said it's only 1-2mm too long, so I want to trim it down to go back to the 5mm spacer on top.

How is the best way to trim this 1-2mm off?
I have access to a proper bench belt sander, so could I do it with that (it's got a proper bench so I can get it 100% perpendicular)
Or does it have to be cut?

paulbnix

Surely take it back to them so they can correct the mistake they made in not cutting it short enough.
Next time cut it yourself with a hacksaw.

dannbodge

paulbnix wrote:

Surely take it back to them so they can correct the mistake they made in not cutting it short enough.
Next time cut it yourself with a hacksaw.

That's miles more effort.
I can sand it in my lunchtime (and replace the headset bearings at the same time). Taking it back to the LBS involves booking it in, taking it then collecting it again.

Matthewfalle

mark stem where you want to cut it

remove good stem and spacers.

stick an old stem so you can use it as a cutting guide where you want to cut it.

get a hacksaw and cut it

smooth off.

reassemble.

you don't even have to take the forks off if someone holds it for you.

its just cutting a carbon tube. no need for belt sanders etc.

Alejandrosdog

Or stick a thin spacer on top of your stem. No cutting required, this gives you flexibility if at some point in future you fit a deeper stem (some aero stuff). You’ve also got room to move if you ever need to rise it up

Ben6899

Wear a suitable mask.

Matthewfalle

Ben6899 wrote:

Wear a suitable mask.

full Romeo 4 I'd suggest.

then again, if doing it outside with no intention of sniffing or licking anything absolutely no reason to wear a mask. it a carbon tube.

Romeo 4 or nothing

#livingontheedge

Ben6899

Matthewfalle wrote:

Ben6899 wrote:

Wear a suitable mask.

full Romeo 4 I'd suggest.

then again, if doing it outside with no intention of sniffing or licking anything absolutely no reason to wear a mask. it a carbon tube.

Romeo 4 or nothing

#livingontheedge

Which is worth pointing out to someone who is worried about the actual cutting process. One doesn't want to be breathing in carbon fibre dust voluntarily though.

dannbodge

Okay I'll give sanding it a go.

I don't think I'll be taking enough off to actually cut it.

I'll make sure the extraction is on and I've got a mask on

Alejandrosdog

3mm is plenty to cutoff. but since you have concerns about this, leave it there and a a spacer. Plenty of pros have that set up. Next time it goes to the lbs they can rectify their mistake if you want them to still.

Sanding is just fannying around.

dannbodge

Alejandrosdog wrote:

3mm is plenty to cutoff. but since you have concerns about this, leave it there and a a spacer. Plenty of pros have that set up. Next time it goes to the lbs they can rectify their mistake if you want them to still.

Sanding is just fannying around.

It's only 1 or 2 that need to come off.
I already have a spacer. I just want to go back to a 5mm rather than the 10mm that it currently has on it.

Matthewfalle

or just do it properly and slam it

#PRO
#doitproper

keef66

If they needed to add 5mm to the setup to get it to work, you'll need to chop 5mm off the steerer to remove it, otherwise you'll be back where you started...

I'd recommend sawing. Sanding 5mm off is going to put a lot of sideways strain on the very end of the steerer.

Alejandrosdog

Matthewfalle wrote:

or just do it properly and slam it

#PRO
#doitproper

Go pro or go home

Alejandrosdog

err Dan, just a small point, the upper clamping point of the stem will be on the steerer tube still wont it???

#deathtrap

keef66

Alejandrosdog wrote:

err Dan, just a small point, the upper clamping point of the stem will be on the steerer tube still wont it???

#deathtrap

Could depend on the type of steerer bung and what the manufacturers of the fork say.

Some bungs can sit below the top of the steerer tube and have the potential to allow clamping at an unsupported point. Some manufacturers insist on a spacer above the steerer to avoid clamping the very end.

Others like the one supplied with my CR1 sit slightly proud of the top of the steerer so it is supported internally right to the top. Scott say no spacers above the stem.

Matthewfalle

Alejandrosdog wrote:

Matthewfalle wrote:

or just do it properly and slam it

#PRO
#doitproper

Go pro or go home

this x 1,000000000000000

leaving c.5mm is just pointless. its like getting a date with TDSD but deciding to take Janet Street Porter instead.

#goPRO

dannbodge

keef66 wrote:

If they needed to add 5mm to the setup to get it to work, you'll need to chop 5mm off the steerer to remove it, otherwise you'll be back where you started...

I'd recommend sawing. Sanding 5mm off is going to put a lot of sideways strain on the very end of the steerer.

No I want to run a 5mm spacer above the stem.
The current set up was cut slightly too long to allow me to do that with the top cap that I use, so I have to use a 10mm one.

They said the steerer is too long to run the 5mm one (I was getting clicking and creaking issues).

I just want to lose the 1-2mm to let me run my 5mm spacer again as the 10mm looks crap.

Alejandrosdog wrote:

err Dan, just a small point, the upper clamping point of the stem will be on the steerer tube still wont it???

#deathtrap

Yeah of course. I'm not silly
There is still steerer coming out of the top of the stem (2-3mm)

Alejandrosdog

Dannbodge wrote:

keef66 wrote:

If they needed to add 5mm to the setup to get it to work, you'll need to chop 5mm off the steerer to remove it, otherwise you'll be back where you started...

I'd recommend sawing. Sanding 5mm off is going to put a lot of sideways strain on the very end of the steerer.

No I want to run a 5mm spacer above the stem.
The current set up was cut slightly too long to allow me to do that with the top cap that I use, so I have to use a 10mm one.

They said the steerer is too long to run the 5mm one (I was getting clicking and creaking issues).

I just want to lose the 1-2mm to let me run my 5mm spacer again as the 10mm looks crap.

Alejandrosdog wrote:

err Dan, just a small point, the upper clamping point of the stem will be on the steerer tube still wont it???

#deathtrap

Yeah of course. I'm not silly
There is still steerer coming out of the top of the stem (2-3mm)

Worth asking around here

Matthewfalle

why do you want that spacer out of interest?

dannbodge

Matthewfalle wrote:

why do you want that spacer out of interest?

Just prefer a little spacer above the stem.

Done it now.
Ended up cutting it anyway as there was more poking out the top than I originally thought.