Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

CF / Thomson question

Old 04-11-07, 09:49 PM
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CF / Thomson question

I was thinking of picking up a Thomson post (replacing Carbon seatpost) for a CF bike, If I get a Thomson post do I still need to worry about using a torque wrench since by bike is CF?
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Old 04-11-07, 10:02 PM
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There's a good chance your bike has aluminum inside the seat tube area. The use of a torque wrench isn't necessary...just don't gorilla tighten it down. And this is coming from a less than 1 year old 'roadie' who does all maintanence.
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Old 04-11-07, 10:32 PM
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you should really use a torque wrench for EVERY fastener. That being said, as a mechanic that puts together 10's of bikes a day I don't. But on my side I am used to how tight a bolt needs to be by feel. If you're not sure, use a torque wrench.
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Old 04-11-07, 10:40 PM
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I purchased a new made-in-china clicker torque wrench that was less than $30 on Ebay shipped. It said it was accurate +/-4% which is more precise than my guestemeter.

You may want to try that out. Make sure it covers the range of bike fasteners. Most 1/4 drive ones are in that range.

similar item:
http://cgi.ebay.com/NEW-1-4-DRIVE-TO...QQcmdZViewItem
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Old 04-11-07, 10:43 PM
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Harbour Freight is your friend if you need cheap (adequate, better-than-nothing type) tools.

Mac
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Old 04-11-07, 10:56 PM
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Originally Posted by sac02
Harbour Freight is your friend if you need cheap (adequate, better-than-nothing type) tools.

Mac
Thanks for the tip, we have one of those in town!
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Old 04-12-07, 05:21 AM
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I have a Thomson post on a CF bike and it is a great combination. Post retention is much better then the steel frame I had the Thomson in with much less torque. This is mostly because of the seat tube collar design on my new CF bike. The issue of using a torque wrench comes up a lot. For those that have a lot of mechanical experience with the exception of automotive or other machine applications....say torque uniformity like on cylinder head gaskets etc, I never use one for bicycle builds even though I own a couple. This is in part due to I run slightly lower torques on my bike builds then mfr. specs anyway as I am a bit more vigilant about checking my torques over time. Many others like Sheldon Brown don't use a torque wrench on a bicycle either but these are experienced builders. Carbon fiber though very strong has less fracture resistance compared to more ductile steel and hence why torques are generally lower. The good news is CF is very strong and therefore can tolerate a high level of stress though with modest elongation (strain) without permanent deformation, but if you exceed the yield point, unlike steel for example, the material will fracture abruptly. An engineering sidebar is...because CF has such a high modulus of elasticity this makes escalation of torque more abrupt. In other words as you torque against a CF component, torque increases fastest then a steel or aluminum part so you have to be careful on two levels really. Also, aside from abrasion resistance, this is one reason you don't see fasteners made out of CF. For seat post tighting a suggestion is always err on the side of low torque. This btw is not a bad philosophy whatever materials you are working with. What you do is insert the seat post and tighten the pinch bolt collar just over finger tight...a bit more to secure the post. Mark the post with tape and ride the bike. If the post slips then tighten it just a bit more. A CF bike with aluminum seat post...particularly a Thomson post which is mildly serrated is a great combination. Thomson posts like their new X2 stems are beautifully engineered, both being CNC milled out of solid aluminum with material in the right places versus cast or forged counterparts...light and strong but without undo stiffness.
HTH,
George

Last edited by biker7; 04-12-07 at 05:58 AM.
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Old 04-12-07, 06:28 AM
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Originally Posted by biker7
I have a Thomson post on a CF bike and it is a great combination. Post retention is much better then the steel frame I had the Thomson in with much less torque. This is mostly because of the seat tube collar design on my new CF bike. The issue of using a torque wrench comes up a lot. For those that have a lot of mechanical experience with the exception of automotive or other machine applications....say torque uniformity like on cylinder head gaskets etc, I never use one for bicycle builds even though I own a couple. This is in part due to I run slightly lower torques on my bike builds then mfr. specs anyway as I am a bit more vigilant about checking my torques over time. Many others like Sheldon Brown don't use a torque wrench on a bicycle either but these are experienced builders. Carbon fiber though very strong has less fracture resistance compared to more ductile steel and hence why torques are generally lower. The good news is CF is very strong and therefore can tolerate a high level of stress though with modest elongation (strain) without permanent deformation, but if you exceed the yield point, unlike steel for example, the material will fracture abruptly. An engineering sidebar is...because CF has such a high modulus of elasticity this makes escalation of torque more abrupt. In other words as you torque against a CF component, torque increases fastest then a steel or aluminum part so you have to be careful on two levels really. Also, aside from abrasion resistance, this is one reason you don't see fasteners made out of CF. For seat post tighting a suggestion is always err on the side of low torque. This btw is not a bad philosophy whatever materials you are working with. What you do is insert the seat post and tighten the pinch bolt collar just over finger tight...a bit more to secure the post. Mark the post with tape and ride the bike. If the post slips then tighten it just a bit more. A CF bike with aluminum seat post...particularly a Thomson post which is mildly serrated is a great combination. Thomson posts like their new X2 stems are beautifully engineered, both being CNC milled out of solid aluminum with material in the right places versus cast or forged counterparts...light and strong but without undo stiffness.
HTH,
George
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Old 04-12-07, 06:29 AM
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Originally Posted by jjmolyet
I was thinking of picking up a Thomson post (replacing Carbon seatpost) for a CF bike, If I get a Thomson post do I still need to worry about using a torque wrench since by bike is CF?
you don't need a torque wrench if you have experience and a good feel for tightening a multitude of fasteners.
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Old 04-12-07, 06:46 AM
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Originally Posted by mx_599
Are you the dude on here that had the sex change?
George
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Old 04-12-07, 06:48 AM
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Originally Posted by biker7
Are you the dude on here that had the sex change?
George
not sure what you're referring to. do you have a link?
Brian
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Old 04-12-07, 06:50 AM
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Originally Posted by biker7
I have a Thomson post on a CF bike and it is a great combination. Post retention is much better then the steel frame I had the Thomson in with much less torque. This is mostly because of the seat tube collar design on my new CF bike. The issue of using a torque wrench comes up a lot. For those that have a lot of mechanical experience with the exception of automotive or other machine applications....say torque uniformity like on cylinder head gaskets etc, I never use one for bicycle builds even though I own a couple. This is in part due to I run slightly lower torques on my bike builds then mfr. specs anyway as I am a bit more vigilant about checking my torques over time. Many others like Sheldon Brown don't use a torque wrench on a bicycle either but these are experienced builders. Carbon fiber though very strong has less fracture resistance compared to more ductile steel and hence why torques are generally lower. The good news is CF is very strong and therefore can tolerate a high level of stress though with modest elongation (strain) without permanent deformation, but if you exceed the yield point, unlike steel for example, the material will fracture abruptly. An engineering sidebar is...because CF has such a high modulus of elasticity this makes escalation of torque more abrupt. In other words as you torque against a CF component, torque increases fastest then a steel or aluminum part so you have to be careful on two levels really. Also, aside from abrasion resistance, this is one reason you don't see fasteners made out of CF. For seat post tighting a suggestion is always err on the side of low torque. This btw is not a bad philosophy whatever materials you are working with. What you do is insert the seat post and tighten the pinch bolt collar just over finger tight...a bit more to secure the post. Mark the post with tape and ride the bike. If the post slips then tighten it just a bit more. A CF bike with aluminum seat post...particularly a Thomson post which is mildly serrated is a great combination. Thomson posts like their new X2 stems are beautifully engineered, both being CNC milled out of solid aluminum with material in the right places versus cast or forged counterparts...light and strong but without undo stiffness.
HTH,
George
Wow, thanks for the detailed info, it's funny how you can take the time to help out a complete stranger and someone wants to complain that you didn't use paragraphs! Thanks for your time and expertise!
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Old 04-12-07, 06:54 AM
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Originally Posted by jjmolyet
Wow, thanks for the detailed info, it's funny how you can take the time to help out a complete stranger and someone wants to complain that you didn't use paragraphs! Thanks for your time and expertise!
well maybe i wanted to read the good info as well...but i only made it 1/4 of the way through and gave up.
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Old 04-12-07, 07:20 AM
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Originally Posted by mx_599
well maybe i wanted to read the good info as well...but i only made it 1/4 of the way through and gave up.
A common lament among the technically illiterate.
George
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Old 04-12-07, 07:24 AM
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Originally Posted by jjmolyet
Wow, thanks for the detailed info, it's funny how you can take the time to help out a complete stranger and someone wants to complain that you didn't use paragraphs! Thanks for your time and expertise!
You're welcome. Torque and CF are worthy of explanation. Some kind of know why CF needs lower torque but that puts a technical bow on it a bit inspite of outcry from the grammar nazis who base perception on style versus substance. I could punctuate it of course, but don't have time.

Thomson makes the best aluminum posts out there for the money IMHO and you would be well served to try one with CF.
Have fun,
George
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Old 04-12-07, 10:29 AM
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Originally Posted by biker7
A common lament among the technically illiterate.
George
no problems here. just remember to hit the "enter" button on your keyboard. it's really easy. just like this:

brian

ps still waiting on that sex change link or whatever you're talking about?
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Old 04-12-07, 10:47 AM
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Originally Posted by mx_599
no problems here. just remember to hit the "enter" button on your keyboard. it's really easy. just like this:

brian

ps still waiting on that sex change link or whatever you're talking about?
Sorry bro but ain't gonna happen. My lack of attention to syntax is a deliberate effront to board members like yourself who never have anthing of substanstance to contribute. I have to give the trolls like you something to respond to.
George
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Old 04-12-07, 10:52 AM
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Originally Posted by biker7
Sorry bro but ain't gonna happen. My lack of attention to syntax is a deliberate effront to board members like yourself who never have anthing of substanstance to contribute. I have to give the trolls like you something to respond to.
George
wow. someone is having a grumpy day. i make a light hearted suggestion to a post and receive multiple personal attacks. no troll here. i contribute with substance.
brian
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Old 04-12-07, 10:57 AM
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Originally Posted by mx_599
wow. someone is having a grumpy day. i make a light hearted suggestion to a post and receive multiple personal attacks. no troll here. i contribute with substance.
brian
Not grumpy at all. Trolling for grammar is a common theme on here. I grow weary of having to respond which I suppose I shouldn't.
Now run along junior and provide your pansy a$$ grammar advice elsewhere OK?
How's that?

George
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Old 04-12-07, 11:10 AM
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Originally Posted by biker7
Not grumpy at all. Trolling for grammar is a common theme on here. I grow weary of having to respond which I suppose I shouldn't.
Now run along junior and provide your pansy a$$ grammar advice elsewhere OK?
How's that?

George
still the personal attacks. make sure you take an anti-stress vitamin tonight. you really need to relax. i don't capitalize. i made no mention of your recent typos either. where did i make grammar trolling remarks? i didn't know spacing ideas was grammar. just trying to make your knowledge easier to assimilate on an internet forum and this is the thanks i get...



brian
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Old 04-12-07, 11:15 AM
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Originally Posted by blonduathlongrl
**********?
and George, seriously Im saying this in a friendly way. I never read your posts because they are so long and condensed into one paragraph.
You need to use paragraphs a little more
Then I will respond in like kind Karen. Please do not read my posts. Ignore them if you would. I could do without the criticism which this board is so replete with.

We are all fellow cyclists that come from different backgrounds. I for example do not nit pick your syntax in spite of it being replete with errors because I recognize English is your second language. I accept you in other words which is in limited supply on this board.

Re-read what the OP wrote in response. My response was directed to him. He appreciated the technical discourse. It likely wouldn't resonate with you anyway. There are very few technical people on this board including you. That is my contribution. I have never read anything technical from you which is fine, but then I don't expect anything from anybody here other then a bit more acceptance and courtesy.

Please...simply add me to your ignore list.
Thank you,
George
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Old 04-12-07, 11:19 AM
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Originally Posted by mx_599
still the personal attacks. make sure you take an anti-stress vitamin tonight. you really need to relax. i don't capitalize. i made no mention of your recent typos either. where did i make grammar trolling remarks? i didn't know spacing ideas was grammar. just trying to make your knowledge easier to assimilate on an internet forum and this is the thanks i get...



brian
Brian,
I am sorry you took it that way...well kinda
Look, this isn't too hard to comprehend...really.
You fired a shot over the bow first. Get that? You criticized the style of my writing. You made no comment relative to the substance of what I wrote. I accept you for example for not being too smart.
Re-read what the OP responded. He said it perfectly. You try to help out a stranger and you get criticized. Please add me to your ignore list.
Thanks,
George
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Old 04-12-07, 11:19 AM
  #23  
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Back on topic. Of anything CF I have had bad luck with it is seat posts. I had an Easton one that slid on me. I had a cheap no name one that just flat out broke on me and for the longest time I used the Giant Aero post (that came on stock Giants for a while).

I had a Thomson Elite post that someone let me have and I strayed away from it for my blind love of Carbon Fiber. This year I started loosing that blind part and started looking at ways I could improve my bike in areas without carbon...if it truly was a better choice.

The first thing to go was the seatpost.....I am very happy with the Thompson now...Also it weights quite a bit less than the Aero post as well. In fact I have a new frame on order and it comes with its own seatpost, I have not decided what I will do yet....we will see...
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Old 04-12-07, 11:21 AM
  #24  
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Originally Posted by biker7
Then I will respond in like kind Karen. Please do not read my posts. Ignore them if you would. I could do without the criticism which this board is so replete with.

We are all fellow cyclists that come from different backgrounds. I for example do not nit pick your syntax in spite of it being replete with errors because I recognize English is your second language. I accept you in other words which is in limited supply on this board.

Re-read what the OP wrote in response. My response was directed to him. He appreciated the technical discourse. It likely wouldn't resonate with you anyway. There are very few technical people on this board including you. That is my contribution. I have never read anything technical from you which is fine, but then I don't expect anything from anybody here other then a bit more acceptance and courtesy.

Please...simply add me to your ignore list.
Thank you,
George
wow, this is why I had originally taking my friendly post off. I knew if you got critisized even in a positive way that you would resolve this with insults.
It's OK.. I dont really need to read posts from someone who assume not many people are at his level.

ohh.. here's a link to your self admitted favorite video you have posted repetivly about... and yes! I must of not been savvy enough to really enjoy it as much as you do! ahhh, a sign of poor intellectual level again.. poor me, well, life goes on!
like you'd say "lol"!
( post 139)
http://www.bikeforums.net/showthread...21#post4217321

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Old 04-12-07, 11:23 AM
  #25  
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Is another manufacturer of quality non-setback posts? I like the Thompson, and I've had them previously but I don't care to shell out $100 again. I hope to replace my carbon set-back post for fitting reasons...
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