# Carbon fiber everything.....where to clamp?



## jerdawg (Jun 14, 2012)

I am thinking about getting a full carbon fiber bike soon; and came up with this question:

Using a repair stand...such as the "Park Tool" which I own normally clamps on the top tube of the bike ( or atleast that's where I clamp my aluminum framed bike) where do you clamp it if the frame and seat post is all made of carbon?

I hope this is not a dumb question....


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## PJ352 (Dec 5, 2007)

jerdawg said:


> I am thinking about getting a full carbon fiber bike soon; and came up with this question:
> 
> Using a repair stand...such as the "Park Tool" which I own normally clamps on the top tube of the bike ( or atleast that's where I clamp my aluminum framed bike) *where do you clamp it if the frame and seat post is all made of carbon?*
> 
> I hope this is not a dumb question....


The seat post.


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## RoadBoy1 (Oct 1, 2011)

You have two options and only two.

1) You must remove the carbon fibre seatpost and replace it with an aluminum or alloy seatpost and then clamp that seatpost into the workstand.

2) Buy and use a tripod type repair stand that holds the bike by cradling the bottom bracket and clamps the fork ends into some sort of quick release. Park and a couple of others makes this type of repair stand. The Park PRS-21 is an example.

I have never owned a carbon fibre bike, and never will but I have always used a tripod type repair stand. They are much sturdier and safer plus they lower (or eliminate) the possibility of over clamping a frame tube and wrecking a frame.


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## RoadBoy1 (Oct 1, 2011)

PJ352 said:


> The seat post.


It's a carbon fibre seatpost. The carbon fibre enima that can result from a carbon seatpost snapping off after it has been over tightened into a workstand clamp are not fun!!


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## PJ352 (Dec 5, 2007)

RoadBoy1 said:


> It's a carbon fibre seatpost. The carbon fibre enima that can result from a carbon seatpost snapping off after it has been over tightened into a workstand clamp are not fun!!


What do you think support 50% of your weight on the bike? Most manufacturers recommend clamping the bike at the seat post, CF or not. I've done so for years - never had a problem.

As far as over tightening _any_ CF part/ component, user discretion is advised and torque values should be adhered to. 

BTW, FWIW Specialized CF posts have a weight restriction of ~225 lbs.


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## jerdawg (Jun 14, 2012)

2) Buy and use a tripod type repair stand that holds the bike by cradling the bottom bracket and clamps the fork ends into some sort of quick release. Park and a couple of others makes this type of repair stand. The Park PRS-21 is an example.

Iv'e seen these....I guess I should have noted....besides using a tripod stand.

Thanks for your advise gentlemen


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## cxwrench (Nov 9, 2004)

RoadBoy1 said:


> You have two options and only two.
> 
> 1) You *must remove the carbon fibre seatpost and replace it with an aluminum or alloy seatpost and then clamp that seatpost into the workstand.*
> 
> ...



you might want to go around to every shop in the country and let the mechanics know they're doing it wrong. i for one an glad you are so knowledgeable about this even though you've never owned a carbon frame. i guess i'm just lucky that none of the thousands of carbon posts i've clamped over the last who-knows-how-many years has broken. 

i will agree w/ you on the workstand...i love the PRS-20/21 and the Tacx i have.


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## xjbaylor (Dec 28, 2006)

RoadBoy1 said:


> You have two options and only two.


3.









Or of course you could just clamp your seatpost, carefully, in a normal workstand like everyone else does. It takes VERY little clamping force to hold a 15lb bike.


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## mazzmond (Jun 18, 2011)

The seat post, I have a repair stand and all my bikes have carbon fiber posts and have been clamping the post for years. You're not going to hurt it.


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## ParadigmDawg (Aug 2, 2012)

Been clamping to a carbon seat post for years...


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## tlg (May 11, 2011)

RoadBoy1 said:


> You have two options and only two.
> 
> 1) You must remove the carbon fibre seatpost and replace it with an aluminum or alloy seatpost and then clamp that seatpost into the workstand.
> 
> ...


Nice that you're the authority on something you've never used. 
I'd love to hear your rationale of why a seatpost, which can support a 150-200lb person can't support a 15-20lb bike. 

I know you've said there are only 2 possible options. 
But I guess I break your rules with a 3rd option. I clamp mine on the top tube.


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## RyleyinSTL (Aug 6, 2012)

My bike shop clamps everything by the seat post generally, carbon or not. That said, when doing bottom bracket work or the like, the bikes usually end up on a custom made device similar to a Euro/Sprint stand.

I'm eyeing one of these for the house:
Sprint Work Stand


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## laffeaux (Dec 12, 2001)

If you clamp your work stand tight enough to crush a carbon seat post, you likely should likely not be working on your own bike. A moderate amount of clamping force from a rubber-coated clamp will not hurt the post - regardless of material.


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## tlg (May 11, 2011)

laffeaux said:


> If you clamp your work stand tight enough to crush a carbon seat post, you likely should likely not be working on your own bike. A moderate amount of clamping force from a rubber-coated clamp will not hurt the post - regardless of material.


I think more of the concern is cranking on your bike while it's hanging from the seatpost, rather than it getting crushed in a rubber clamp.


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## Erion929 (Jun 10, 2010)

I clamp my carbon seat post all the time, although I use a 1/8" thick rubber tubing or a microfiber towel around it...just for piece of mind.

**


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## bayAreaDude (Apr 13, 2012)

I put my bike in my trainer when I need a workstand, which connects at the rear skewer. Or I just flip it upside down.


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## JonathanGennick (May 8, 2007)

Park makes a seat post replacement just for clamping. At least one local shop I know uses it.


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