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CF frame in a home workstand - best way to clamp?

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CF frame in a home workstand - best way to clamp?

Old 07-03-16, 06:05 PM
  #26  
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Thanks for the all the help and input guys. I tried again today to clamp it via the seatpost and it turns out there's about 1/3" of space left, so I was able to successfully clamp the seatpost.
The other day I was holding it up and just eyeballing it and it didn't look like enough room. So, problem solved!
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Old 07-04-16, 12:53 AM
  #27  
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Regarding clamping the top tube, it's not just the static force of the clamp that can damage the frame. No matter how lightly the tube is clamped, if anything hits or knocks the bike while in the stand it can get damaged by the clamp. It doesn't take a hard knock at the rear wheel for example to translate into a lot force at the clamp.
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Old 07-04-16, 03:04 AM
  #28  
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Some carbon top tubes have been known to crack from fairly light impacts, or sitting on them. Seatposts on the other hand, are designed to handle camping forces.
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Old 07-04-16, 12:21 PM
  #29  
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From everything I have read, seen, and been told, seatpost only.
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Old 07-04-16, 01:29 PM
  #30  
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I'm sorry if I'm missing something or if this comes across the wrong way, but why would you need to secure the bike if all you're doing are adding bottle cages and a seat bag?

For real maintenance, I second the backup alloy seat post argument.
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Old 12-16-20, 02:21 PM
  #31  
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Sorry to revive old thread but putting EMPHASIS on this ...

DO NOT CLAMP THE TOP TUBE ....

I clamped it to the top tube very loosely when i put my fenders on my NEW 2021 CHECKPOINT ... didn't think anything of it as it was not very tight just enough to hold it still ... went to work on it again today adding more accessories and frame tape and found a nice crack on the frame where the clamp goes ... I feel like a total freaking idiot but this is my first ever CF bike and didn't think 'oh ... this might not be a good idea ...

right now I am praying the shop manager can work some magic and get it replaced for me ... cannot be done under warranty (its my fault so why would it ) ... but I really hoping the christmas spirit is shinning on me and they will replace it and not bust my wallet ...

People DON'T be like me ... clamp by the seatpost
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Old 12-16-20, 04:53 PM
  #32  
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Buy one of these! Allen Adaptor Bar Rack Accessory for Non-Conventional Bicycle Frames - 900B
cheap insurance
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Old 12-16-20, 05:03 PM
  #33  
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Originally Posted by EndUser2016 View Post
Sorry to revive old thread but putting EMPHASIS on this ...

DO NOT CLAMP THE TOP TUBE ....

I clamped it to the top tube very loosely when i put my fenders on my NEW 2021 CHECKPOINT ... didn't think anything of it as it was not very tight just enough to hold it still ... went to work on it again today adding more accessories and frame tape and found a nice crack on the frame where the clamp goes ... I feel like a total freaking idiot but this is my first ever CF bike and didn't think 'oh ... this might not be a good idea ...

right now I am praying the shop manager can work some magic and get it replaced for me ... cannot be done under warranty (its my fault so why would it ) ... but I really hoping the christmas spirit is shinning on me and they will replace it and not bust my wallet ...

People DON'T be like me ... clamp by the seatpost
Sorry to hear; that's terrible. I've passed or stopped in at cyclist stopping points and am always a bit surprised to see someone basically sitting on their CF top tube in lieu of a chair being available. I keep thinking it will collapse under them, but haven't witnessed yet.
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Old 12-16-20, 05:23 PM
  #34  
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Originally Posted by mgopack42 View Post
Can't imagine it not marking up a nice carbon frame.

Check this out.
https://roadbikeaction.com/upgrade-y...carbon-frames/
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Old 12-16-20, 05:28 PM
  #35  
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Originally Posted by Sy Reene View Post
Sorry to hear; that's terrible. I've passed or stopped in at cyclist stopping points and am always a bit surprised to see someone basically sitting on their CF top tube in lieu of a chair being available. I keep thinking it will collapse under them, but haven't witnessed yet.

Yeah I was just floored to find this today but i am happy i found it when i did vs later when I was riding and the frame failed at speed ... just totally wrecked when my hand went down to pickup the bike and i felt a rough marker and looked to find this crack ... I was not that hard on the thing with the clamp when i put it on the fenders and 3M tape ...so i thought but obviously it was too much for the frame -_- I really hoping my LBS will have mercy on me ... but I was straight honest with what happened ... occurred to me to play dumb but my conscience tells me always its always best to tell the truth ... it is my screw up and i just really hope it does not cost me much ... plus I do NOT believe i am the first ever moron to do this so yeah ... I just hope I don't have to drop too much $$$ on what has been a $6000 bike after all the bells and whistles i bought plus sales tax ... and worse ... this was a replacement for a STOLEN bike not four months ago ... so i am once again bike-less

Last edited by EndUser2016; 12-16-20 at 05:59 PM.
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Old 12-16-20, 05:43 PM
  #36  
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Originally Posted by GlennR View Post
Can't imagine it not marking up a nice carbon frame.

Check this out.
https://roadbikeaction.com/upgrade-y...carbon-frames/
The adapter i linked clamps on the headset area and the seat post. never touches the frame. the one you linked to is WAY nice, but I seem to remember that one is mucho expensivo!
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Old 12-16-20, 06:02 PM
  #37  
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Originally Posted by mgopack42 View Post
The adapter i linked clamps on the headset area and the seat post. never touches the frame. the one you linked to is WAY nice, but I seem to remember that one is mucho expensivo!
Even a cheap CF bike is over $2000 and some are over $12,000,
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Old 12-16-20, 06:04 PM
  #38  
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Originally Posted by the sci guy View Post
I tried clamping it by the seat post, but there wasn't enough seatpost showing to clamp it.



Bike is a new Specialized Roubaix SL4 Sport.
Here's what the bike looks like, it has a drop top tube. so if there's not enough exposed seat postt hen the bike has to be too big or you have really short legs.

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Old 12-16-20, 06:15 PM
  #39  
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Clamping by the top tube is fine if done properly:

Tighten until the first clearly audible "click" then back off 1/2 turn.
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Old 12-16-20, 06:32 PM
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Originally Posted by Kapusta View Post
Clamping by the top tube is fine if done properly:

Tighten until the first clearly audible "click" then back off 1/2 turn.
You forgot the smiley face.
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Old 12-16-20, 06:36 PM
  #41  
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Originally Posted by mgopack42 View Post
The adapter i linked clamps on the headset area and the seat post. never touches the frame. the one you linked to is WAY nice, but I seem to remember that one is mucho expensivo!

Well as I have had time to read up on my recent goof Trek just recommends you get a aluminum seat post the will go into the place but I like the idea of the BAR with the rubber flaps and clamping to that ... it is no different than a bike rack really ...
.. figured I would order a hitch to go with this rack my neighbor gave me for free ... yeah SORRY ... hanger rack style plus carbon fiber also not good combination! ...

damn world hates my guts right now is my present working theory
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Old 12-16-20, 06:39 PM
  #42  
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Originally Posted by Kapusta View Post
Clamping by the top tube is fine if done properly:

Tighten until the first clearly audible "click" then back off 1/2 turn.

Yeah ... I thought I was very gentle with mine and my reward is a busted FRAME ... NO clamping by the FRAME is a HORRIBLE IDEA!
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Old 12-16-20, 06:41 PM
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Originally Posted by GlennR View Post
You forgot the smiley face.
Oops! I'll try that again

Tighten until the first clearly audible "click", smile, then back off 1/2 turn.
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Old 12-16-20, 06:47 PM
  #44  
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Originally Posted by Kapusta View Post
Oops! I'll try that again

Tighten until the first clearly audible "click", smile, then back off 1/2 turn.
Better
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Old 12-16-20, 07:35 PM
  #45  
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Originally Posted by mcours2006 View Post
I've read that you can buy a cheap alloy seatpost to use for this purpose. Just do do any sort of heavy duty wrenching work on it.
a cf seat post is designed to clamp anywhere along their length, given that the post will be clamped into
the frame at different spots given the height of
the rider.

they are much more durable than many think.

we clamp the stokers bars on a cf seat post on our tandem and have done for years. That introduced forces that are an order of magnitude above clamping
to a stand
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Old 12-16-20, 07:46 PM
  #46  
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I have Silca Hirobel Frame Clamp Really nice and works really well.


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Old 12-17-20, 11:45 PM
  #47  
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Originally Posted by GlennR View Post
Here's what the bike looks like, it has a drop top tube. so if there's not enough exposed seat postt hen the bike has to be too big or you have really short legs.

First off, I asked this question over 4 years ago. Secondly, I no longer even have the bike because the frame cracked at the seat tube collar - unrelated to this - in December 2019.
Third, the bike was sized to me properly, I do have shortish legs, and there was plenty of seatpost showing and it would clamp it, but it basically took up he whole length. I don’t think hat stupid CGR ugly seatpost bird beak helped either.
Lastly, here’s what my bike looked like (my pic)

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Old 12-18-20, 12:12 AM
  #48  
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I gently clamp the top tube with just enough grip so it doesn't fall off. The clamp has rubber on it and frankly I've never worried about it, if you can grab and carry the bike by the top tube, gently clamping it isn't any different. That's good enough for cleaning and fine adjustments so on.

If I need to apply some force to the bikes, like removing the crankset, hammering out the bottom bracket or so on, then I set it on the floor.
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Old 12-18-20, 12:27 AM
  #49  
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Originally Posted by Kapusta View Post
Oops! I'll try that again

Tighten until the first clearly audible "click", smile, then back off 1/2 turn.
Now THIS is funny!

Goddamn.
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Old 12-18-20, 10:21 AM
  #50  
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Originally Posted by TMonk View Post
You're not going to crush a CF frame by clamping it hard, but you could induce some micro fractures that propagate over time.
You can easily crush a lightweight carbon frame with a clamp style stand. Since most of my bikes are Carbon I upgraded to a tray style stand that hold by the fork and BB.
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