Head tube compression bolt--what does it connect to?

tlippy

Active Member
In this picture, is the star nut just pressed into the tube? Probably why a specific torque is advised? Looks like an overtighten could pull the nut up and out of position?
 

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JRA

Well-Known Member
More like pounded in. There is a tool that the star fangled nut screws onto then you whack it in there and the tool stops it at the proper depth.
 

Papadevo

New Member
It sets the load on the bearing. Once you clamp them stem down, the bolt and cap are essentially decorative. You can take off the cap without effects to steering etc. There is a safety element in the redundancy so keeping it all there is a positive.
 

grahamB

New Member
Crap.. so my stem bolt sheered off when torquing it fairly flush to the star nut. Not sure if I had a weak bolt or been doing too many weights. I did not see any specific torque guidelines apart from torque it until it does not impede movement of the steering....

Is this an issue or is it really decorative ? It’s gonna be a PITA to get the remaining bolt out. Any suggestions?
 

JRA

Well-Known Member
If you were torquing the stem bolt hard enough to break it you were pre-loading the headset bearings way too much. I don’t think you still have the idea of how it all works....
 

grahamB

New Member
mechanically All is working fine apart from the broken bolt. Just questioning how critical this is for holding stem and fork together once handlebars are clamped down.
 

FlatSix911

Well-Known Member
Crap.. so my stem bolt sheered off when torquing it fairly flush to the star nut. Not sure if I had a weak bolt or been doing too many weights.

I did not see any specific torque guidelines apart from torque it until it does not impede the movement of the steering...

Is this an issue or is it really decorative? It’s gonna be a PITA to get the remaining bolt out. Any suggestions?
The stem top-cap bolt is just a pre-load to hold the fork tube tight against the stem... the stem bolts take all of the load when tight.
You could even remove the stem top-cap and bolt once the stem bolts are properly torqued to spec... ;)

To remove the Star nut, just take a deep socket and hammer to tap out the nut through the bottom of the fork.
I recommend that you replace the star nut with a high quality expanding nut that is adjustable to fit your fork.


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Sierratim

Well-Known Member
The stem top-cap bolt is just a pre-load to hold the fork tube tight against the stem... the stem bolts take all of the load when tight.
You could even remove the stem top-cap and bolt once the stem bolts are properly torqued to spec... ;)

To remove the Star nut, just take a deep socket and tap out the nut through the bottom of the fork.
I recommend that you replace the star nut with a high quality expanding nut that is adjustable to fit your fork.


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I agree. Until you want to adjust your handle bar height, you're OK.

We use a piece of metal conduit with one end split open to the ID of the head tube to install and drive out Star nuts. Very effective, and economical (cheap).
 

tlippy

Active Member
If you were torquing the stem bolt hard enough to break it you were pre-loading the headset bearings way too much. I don’t think you still have the idea of how it all works....
I will test that my torque wrench clicks before I crank on that particular bolt. That bolt doesn't require much torque. I'd think its best to feel that one. Too easy to snap it off
 

FlatSix911

Well-Known Member
I will test that my torque wrench clicks before I crank on that particular bolt.

That bolt doesn't require much torque. I'd think its best to feel that one. Too easy to snap it off
I agree... don't use a torque wrench on the top cap bolt... just firm thumb tight. ;)