Cutting carbon seatpost - should I?

Just bought a Planet X carbon seat post for my steel frame road bike. Trouble is, it's far too long for my needs. Is it a good idea to cut it, or should I just live with it?

If to cut, what's the best way to do this?

Also, should I use carbon assembly paste (Fiber Grip or similar), regular grease or nothing?

Thanks

No. You'll only save a couple of grams, any mistake would be costly or ,at worst, dangerous.

Just don't.

Yes to grease.

Cut it

Wrap some tape around the region you cutting. Use a fine tooth hacksaw. Be gentle, dont force it. Use a mitre to get it straight. Simples, I've done it plenty times.

It had its chance, just ask the unwanted post nicely to leave and try its luck somewhere else.

I vote +1 to cut it, and don't use grease- it can get into the post and cause it to expand, jamming it in there (or so I have been told by a bike shop mechanic).

Use carbon assembly paste.

Use Tynan's Security Paste™

Available in all good bike stores and some shit ones.

Also you dont necessarily need paste. I ran a carbon post in a steel frame dry no probs. Never slipped

Yep, probably fine- but the increased friction from the paste means that you can run even less tension on the seat-clamp bolt.

My post is a max of 5Nm, but I typically do it up to just under 4Nm in order to have some margin for error- and it's rock solid at that torque value.

just to be clear, 5Nm is the force required to dig a teaspoon full of sugar out of a jar

What type of sugar?

Alan

the thread has taken a good turn

What type of sugar?

regular white granulated, stood next to the kettle, so assume 40% humidity

Yes to grease.

You trollin?

No. You'll only save a couple of grams, any mistake would be costly or ,at worst, dangerous.

you trollin?

With this bit...

No. You'll only save a couple of grams,

...probably not.

With this bit...

any mistake would be costly or ,at worst, dangerous.

...probably so.

With this bit...

Yes to grease.

...definitely.

From experience, don't cut (little to be gained?) and definitely carbon paste.

Cut it

Wrap some tape around the region you cutting. Use a fine tooth hacksaw. Be gentle, dont force it. Use a mitre to get it straight. Simples, I've done it plenty times.

This.

But also use a new blade.

And measure several times before cutting.

So it's, yes, no, maybe.

You guys are so helpful

But thanks for the advice on how to go about it.

Lfgss has ranked me as "Elite", so you should listen to me ;)

I use a tungsten carbide blade on carbon. And I always use carbon assembly stuff. Cut it if you are feeling lucky. Don't if you're not.

just to be clear, 5Nm is the force required to dig a teaspoon full of sugar out of a jar

Even if it was true.... just for some sense of perspective LOOK for their classic Ergopost recommend 2Nm tightening force...

Just bought a Planet X carbon seat post for my steel frame road bike. Trouble is, it's far too long for my needs. Is it a good idea to cut it, or should I just live with it?

If to cut, what's the best way to do this?

**Also, should I use carbon assembly paste **(Fiber Grip or similar), regular grease or nothing?

Thanks

The way I've done it: wrapped adhesive tape to the desired length to achieve clean even cut; used dremel micro motor and a thin cutting disc at low speed (higher speed will raise the temp, and eventually burn the composite filler); moved in circular way gently applying pressure and deepening the cut uniformly on all sides; finally smoothed the cut with a hard rubber wheel at low speed. You can get the separating disc and the rubber wheel in tool shops; or if you know a dental technician s/he may give you some).

I always use carbon paste for better friction (some manufacturers advise against using regular grease); and think torque wrench is a must.

Hope this helps.

^ just get a Ritchey torque key... cheap and lets you safely crank @5Nm all the live long day...