Stem is coming loose help please

sigorman85

Hi i have a pinarello with onda front forks and carbon steer tube i have a deada zero stem fitted with 3 spacers its comes loose after about 30 mins in to a ride i don't want to over tighten it as it could cause damage and i have fitted and tightened it the rite way its not extremely loose but enough for the spacers to start rattling. Is this a star nut problem? As it seems the stem is moving its self up the steering tube by about 1 mm or is there another problem????

Any info or help guys cheers

maringirl

If it is a carbon steerer then it won't be a star nut (I hope!!!) but a bung - it may be the bung was not set in tight enough and has moved up a little when the preload has been done?

fludey

Think you will find bung is normally done up just enough to pre load bearings, think its about 2nm, then the others are in range of 7-9nm to actually secure in place. It might be worth getting torque checked when doing all bolts up and also use some carbon paste on the contact surfaces to help with fit.

sigorman85

May have to buy some carbon paste and torque check it again cheers guys

nicklouse

New build? Sometimes you have to adjust to take the slack up as things bed in.

And as there is a bung in there crushing the steerer is unlikely.

And torque figures are only there for the threads not for the clamping force.

g00se

I have a Deda Zero too and had exactly the same issue. It was because I was torquing up the stem bolts to 4-5NM as per the previous FSA stem (and as it seems for most other stems). But if you check the manual, alloy Deda stem bolts need torquing up to 8 NM. I thought this was a bit high, but if you think about it, that toque is what is required to close the stem clamp - not an indication of the force exerted on the steerer itself.

Also, don't forget to use carbon assembly paste too.

sigorman85

Thanks for the help guys