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Torque on carbon ba...
 

Torque on carbon bars?

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Nukeproof handlebar blurb says refer to stem instructions

Nukeproof stem says 5nm, but doesn't specify carbon bars

TRP brakes say 5-7nm

Never had carbon bars before. Guessing everything at 5nm will be ok?


 
Posted : 05/11/2023 8:56 am
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In the same boat. Even 5nm felt unnecessarily tight for the TRP lever so I only went as tight as I dared where the lever wouldn't move which was 4nm. Also added a little carbon paste.


 
Posted : 05/11/2023 9:01 am
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The NP bars come with grit applied to the finish at the contact points.

Does this negate the need for paste?


 
Posted : 05/11/2023 9:06 am
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personally I just tighten by feel and leave levers slightly loose so that they will twist round the bar if given a hard impact to protect the levers from breaking


 
Posted : 05/11/2023 9:07 am
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I always tighten brake levers, shifters etc holding the short end of the Allen key, always thought stated settings were higher than necessary, but I've always done stem faceplates to 5nm.


 
Posted : 05/11/2023 9:45 am
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5Nm is enough for a stem faceplate.

As above, I like my controls to love in a crash rather than snap so less than faceplate


 
Posted : 05/11/2023 9:46 am
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6nm on stem faceplate.

3nm on grip locks

Bar furniture clamps tight enough that they don’t rotate in normal usage, but not so tight that they won’t move if/when I crash.


 
Posted : 05/11/2023 9:50 am
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Torque values are usually a maximum figure rather than a target 


 
Posted : 05/11/2023 10:18 am
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Stem at 5nM sounds right, and if that's what it says on the stem then all the better. Given the large surface area and compressive load  I expect that the failure point for over-torqueing would be stripping the bolt threads, not weakening the bars.

Brakes and shifters I do by hand, so they're just tight enough that they stay put but can rotate (with a bit of pressure, not "loose"), so that in a crash they can move.


 
Posted : 05/11/2023 11:47 am
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Sram and Shimano brake levers are 5Nm give or take .5Nm. Stem face plates are generally 5Nm. 

Everyone has their own theories on brake lever torque and protection against damage. Personally I've seen too many bars having cuts in them due to low torque on brake lever clamps and the clamps acting as pipe cutters. Which means I've seen too many carbon bars snapped at the brake lever clamp....

I'd rather snap a brake lever blade than a carbon bar, so I tighten roughly to spec. 


 
Posted : 05/11/2023 8:14 pm
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I’ve seen too many bars having cuts in them due to low torque on brake lever clamps and the clamps acting as pipe cutters.

Yeah - the levers should not actually be loose or move in use, to avoid the above. My idea of “being able to rotate” is with some reasonable force applied.


 
Posted : 05/11/2023 11:47 pm
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I’d rather snap a brake lever blade than a carbon bar,

Most folk are worried about a lever hitting the frame and it not being able to rotate enough to avoid severe damage.


 
Posted : 05/11/2023 11:53 pm
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Does this negate the need for paste?

Yeah they don't need paste.

Just do them tight but not vice-like.


 
Posted : 06/11/2023 9:39 am