# Broken seat post bolts- help



## nrob592003 (Nov 5, 2005)

I have a 2010 Trek 5.2 Madone with the integrated seat mast with female seat post. Over the last 1.5 years I have been having problems with the seat post bolt snapping off at the bolt head. 3 times now. Quite annoying to get home. I have been using SS bolts and a torque wrench to put new ones in place. 
Is this a known issue ?
Solutions ?
Go to non-SS bolts to get stronger 12.2 steel ?

I am not a big person. 145 lbs, 6' 1". Ride hills in Northern CA about 3500 miles a year and 350K ft climbing. Corrosion not an issue from water.

Thanks for inputs !


----------



## tlg (May 11, 2011)

How much torque are you using? 

Where are you getting your SS bolts from? Maybe they're poor quality. 

A 12.2 steel bolt would be more that 2x stronger. But you have to worry about it seizing from rust. And I'd be concerned that a 12.2 bolt will be so strong, that whatever is causing your bolts to break is going to cause something else to break instead.


----------



## Tlaloc (May 12, 2005)

If you lightly grease the threads it will help it tighten to the required torque and it won't seize. Or, since you shouldn't be removing this again, you could use blue locktite.

The torque spec for this is only something like 60 inch pounds so it is surprising that the bolt would fail. Beware of over-tightening bolts on your carbon frame - you could damage the frame.

Carbon assembly paste will keep the post from slipping.


----------



## cxwrench (Nov 9, 2004)

Carbon paste, grease the crap outta the bolt. Go 12.2 if you want. Why are you adjusting it so often...travel?


----------



## nrob592003 (Nov 5, 2005)

I torque to spec with torque wrench from bike shop.
Bolts came from bike shop
Not adjusting it often at all, the only time I have adjusted the bolt is when it has broken and had to put in new one.
The bike shop has not been any help on defining a solution so that's why I thought I would try here.


----------

