[dvsman]

Just got myself a brand new '11 Giant Defy 1 and everything is great except the fact that i can 't go more than 5-10 miles without the spoke nipple coming loose to the point where it falls off.

This is the 3rd time its happened. Shop has tried different nipples (brass, alum, 14g, 15g)
and still it doesnt help.

The rims are giant pr-2. Can't find any info on them anywhere.

Any idea what could be causing this? If it helps, im 250lb just started getting into road bikes. I would think a broken spoke would be more akin to too much weight.

 

[brblue]

Just got myself a brand new '11 Giant Defy 1 and everything is great except the fact that i can 't go more than 5-10 miles without the spoke nipple coming loose to the point where it falls off.

This is the 3rd time its happened. Shop has tried different nipples (brass, alum, 14g, 15g)
and still it doesnt help.

The rims are giant pr-2. Can't find any info on them anywhere.

Any idea what could be causing this? If it helps, im 250lb just started getting into road bikes. I would think a broken spoke would be more akin to too much weight.

The spoke tension for a particular spoke varies during the ride , especially when riding out of the saddle. This is more so in case of flexy rims and heavy rider Detensioning the spoke means the nipple can turn almost freely, especially in case the wheel is new and there's no dirt in the rim drilling, inhibiting the nipple to turn.

Also rear wheel non-drive side is very prone to this - especially in case of non-offest rims, in case of the same number of drive side and non drive side spokes, and especially for the wheels with higher spoke count.

If the nipple comes loose then that spoke is not tightened enough to keep the nipple steady / all spokes on that side of the wheel at least, are not tight enough

If the wheel is round and true, and rim had no damage in the past (probably so) the shop can increase tension for all spokes of that wheel.
If that's not doable or it;s not helping try some loctite or some thread - locking compund for that nipple.

If the rim has was hit and spoke tension for that spoke is already low, in order to keep the wheel true, then a new rim can cure this...

 

[FBinNY]

While nipples can vibrate loose, it takes time, and I don't think it would work itself off that fast. Spokes have a fine thread, so if not fully engaged they can seem OK but pop apart under load.

My first suspicion was that the nipple was partially stripped but since you replaced it that's ruled out. But the spoke isn't. if you haven't replaced it, use a caliper to check that the 2mm thread is fully 2.15mm in diameter.

If you're convinced the thread is OK, put a drop of latex paint or liquid paper on the spokes thread and let it dry before threading on the nipple. That'll act like nylok and prevent the nipple from spinning.

Also just in case it's an inadequately tightened OEM wheel, have the shop check tension, and if possible take an extra 1/2 or full turn on all right side spokes, then re-dish the wheel back to the left, and align.

 

[dombey19]

I don't understand how a nipple can "fall off." It comes through the backside of the rim and attaches to the spoke. It might get loose on the spoke, but how can it pull through the rim and fall off?