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Old 11-13-10, 08:41 PM   #1
Cowboy905
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seat keeps slipping down roughly half an inch

Hello,

my seat post keeps slipping down a bit. i've tightened it as hard as i can....it takes a small allen key that i can't get a lot of torque from.

it's a carbon seat post and a carbon frame so i'm scared of tightening it too much.

clearly i need a torque wrench.... a couple questions.

what is a good torque wrench to get?

how come every torque wrench i've seen online is a socket wrench? my fastener takes a small allen key.

thanks.
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Old 11-13-10, 08:49 PM   #2
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are you using carbon assembly paste on the post? for torque wrenches i like dial or open beam type for the stems and seatposts. i have a sturtevant open beam. hex bit sockets are available from many manufacturers and fit right on the torque wrench
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Old 11-13-10, 09:09 PM   #3
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Always use carbon assembly paste on carbon parts and you will have no need to over tighten bolts.

http://www.qbike.com/cgi-bin/find.cg...assembly+paste
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Old 11-13-10, 09:51 PM   #4
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Quote:
Originally Posted by Cowboy905 View Post
Hello,

my seat post keeps slipping down a bit. i've tightened it as hard as i can....it takes a small allen key that i can't get a lot of torque from.

it's a carbon seat post and a carbon frame so i'm scared of tightening it too much.

clearly i need a torque wrench.... a couple questions.

what is a good torque wrench to get?

how come every torque wrench i've seen online is a socket wrench? my fastener takes a small allen key.

thanks.
It'll most likely be a 4mm or 5mm seat collar he's tightening. In which case, it is definitely possible that it is already damaged from overtorquing. And what #2 said, use carbon assembly paste, in addition to double checking that the post is actually the right size for the bike. e.g. 27.2 and 27.0 looks awfully close.
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Old 11-14-10, 03:43 AM   #5
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Warren & Brown make great torque wrenches. You can convert from socket to allen key by buying the socket of the same hex size as the allen key.
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Old 11-14-10, 07:06 AM   #6
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Originally Posted by operator View Post
It'll most likely be a 4mm or 5mm seat collar he's tightening. In which case, it is definitely possible that it is already damaged from overtorquing. And what #2 said, use carbon assembly paste, in addition to double checking that the post is actually the right size for the bike. e.g. 27.2 and 27.0 looks awfully close.
mis-matched seatpost diameter would be my guess, too. or is there something else, e.g., you are a clyde *and* the allen wrench's handle you are using is only 5mm long off the center?
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Old 11-14-10, 09:17 AM   #7
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Quote:
Originally Posted by Cowboy905 View Post
Hello,


clearly i need a torque wrench.... a couple questions.

what is a good torque wrench to get?

how come every torque wrench i've seen online is a socket wrench? my fastener takes a small allen key.

thanks.

A torque wrench is a good investment, but make sure you get one that has the range you need. Do a survey of the fasteners and take note of the recommended torque. As with most tools, price is proportional to quality. Those who wrench a lot often don't use torque wrenches because they've developed the feel with experience. Personally, I use one. I've been eye-ing this wrench and it come with 6 hex bit sockets:
http://www.artscyclery.com/descpage-SHTW.html

Also, these hex bit sockets adapt the square drive on a torque wrench or socket handle to the fastener. You'll need to match the drive of the wrench to the drive of the socket. I use these hex bit sockets almost exclusively in my workshop. When mated to a socket handle or driver, it makes wrenching nice.
http://community.craftsman.com/Craft...-Drive-reviews
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Old 11-14-10, 04:24 PM   #8
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thanks guys. i don't think it's damaged as i've been tightening it with a smell hex key, it's pretty tough to get the strength to over tighten it with such a small key. As for the post size, i imagine it should be the proper size, i bought the bike new fully built already.

thanks for all your help.
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Old 11-17-10, 08:32 PM   #9
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hello, two more questions.

i'm looking to add a Torque Wrench to my Xmas List ( tis the season). i've looked at my bike and it says "max torque 70kgf-cm" what does that mean? is that 70kilograms?

i need to know what to shop for.

also, with the carbon paste, is that a glue? what if i one day needed to adjust the saddle height and the paste is on, would i have trouble?

thanks everyone.
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Old 11-17-10, 09:20 PM   #10
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It means ....Kilogram-force per square centimetre

U need a torque wrench in inches or cm to start with.
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Old 11-17-10, 11:29 PM   #11
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Quote:
Originally Posted by Cowboy905 View Post

i'm looking to add a Torque Wrench to my Xmas List ( tis the season). i've looked at my bike and it says "max torque 70kgf-cm" what does that mean? is that 70kilograms?

.
70 kgf-cm means apply "70 kg of force at 1 cm distance".
It's confusing since force in the metric system is expressed in Newtons (N) and it's more common to see torque expressed as "xx N-m", which means apply "xx N at a 1m distance."

Note, 1 kg-f = 9.81N.

Then 70 kgf-cm = 686.7 N-cm = 6.867 N-m. Thus you will need a torque wrench that can measure up to 6.867 N-m.

Here's an easy to use conversion web site: http://www.onlineconversion.com/torque.htm

By the way, check all the fasteners and see the range of torque values. IIRC, the highest torque value I have is 40 N-m. If you're lucky, one wrench will cover all the fasteners.
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Old 11-18-10, 12:17 AM   #12
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Have a friend that runs a bike shop and swears by these. He tries to sell one to each customer that buys a Trek frame with an aerodynamic seat mast. At $114 per seat mast it is a money saver.

http://www.ritcheylogic.com/dyn_prod.php?p=05-252-100

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