Bicycle Mechanics - Same spoke keeps loosening

..on a set of carbon fairing/aluminum rim wheels that I'm looking at buying.
The seller says that it was lightly crashed quite a while back, and much more recently one spoke has come loose repeatedly. He says that he took it to a bike shop and they couldn't fix it for him (maybe they just wanted to sell him a new wheel, since that was their suggestion?) Though he said that they also didn't have any replacement spokes.
Seems to me that a new spoke & nipple would be the worst case possibility- is there anything else that could cause a particular spoke to come loose on a weekly basis?

FWIW, the wheels are these: http://www.real-design.com/2005/ultrasonic.aspx

I'd be very concerned about any spoke problems in a reduced spoke count wheel like these. Spoke ailments are greatly magnified when you're dealing with those low spoke counts.

As for fixing it... I'd take the thing apart and rebuild it from scratch. Maybe even replace the spokes if any were damaged at all. But I'm picky that way.

I had that problem on some NORMAL rims - it was a bad spoke that had started to fail. it finally broke at the J-bend. I fixed it with a replacement spoke and the wheel held up for a few years but I ended up replacing the rim when some of the spoke holes and eyelets start to fail. I don't know if that was related at all.
YMMV

So generally speaking there isn't a lot else that could be causing a spoke to loosen other than the spoke/nipple? This was my thinking also.

This reminds me of my Cosmic Carbone when an eyelet broke. It was not repairable.

How could the seller tell if the eyelet has broken?
I'm getting a good enough price on these that the rear is basically free anyway.

How could the seller tell if the eyelet has broken?
I'm getting a good enough price on these that the rear is basically free anyway.

You haven't said what the wheel is. If it is a Cosmic Carbone with a broken eyelet you can't really see the eyelet. As you continue to tighten the nipple to straighten the rim, you will run out of threads on the spoke and then there is no way to true the wheel. MAVIC informed me that there was no way to repair the wheel. I think it MIGHT be done if you had the correct eyelet. You also need the correct MAVIC nipple tool.
Someone else was at this forum recently with the same problem.
http://www.bikeforums.net/showthread.php?t=553249&highlight=Cosmic+Carbone+eyelet

..on a set of carbon fairing/aluminum rim wheels that I'm looking at buying.
The seller says that it was lightly crashed quite a while back, and much more recently one spoke has come loose repeatedly. He says that he took it to a bike shop and they couldn't fix it for him (maybe they just wanted to sell him a new wheel, since that was their suggestion?) Though he said that they also didn't have any replacement spokes.
Seems to me that a new spoke & nipple would be the worst case possibility- is there anything else that could cause a particular spoke to come loose on a weekly basis?

FWIW, the wheels are these: http://www.real-design.com/2005/ultrasonic.aspx

Regarding spokes: They seem to be Sapim CX Ray straight pull spokes. Very good spokes, but few have them in the straight pull editions. This store seems to have them though:
http://www.wheelbuilder.com/store/product.php?productid=16181

One cause to why a particular spokes keeps getting loose could be, that the low spoke count wheel requires so high a spoke tension, that it is impossible to reach by just turning the spoke key (which may explain why the LBS had problems). You will then need to side load/compress the rim in such a way that the required spoke tension can be reached. Perhaps not an easy thing to do, and side loading a wheel is always potentially dangerous since wheels aren't designed for lateral forces and may collapse if too much lateral pressure is applied.

There may be other causes such as a cracked rim or hub flange. I would inspect the carefully before buying.

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Regards

Sounds like the nipple is not accessible from the spoke side, and the shop that trued it used a screwdriver from the rim side.

Al1943 (http://www.bikeforums.net/member.php?u=25043), the wheel is a real design ultrasonic 40 as I linked to, above.

Thankfuly, the front (which is the one I really want, he's just tossing in the rear in case I can make it work) was not on the bike when the rear was crashed, and there are not supposed to be any problems with it.

Sounds like the nipple is not accessible from the spoke side, and the shop that trued it used a screwdriver from the rim side.

Al1943 (http://www.bikeforums.net/member.php?u=25043), the wheel is a real design ultrasonic 40 as I linked to, above.

Thankfuly, the front (which is the one I really want, he's just tossing in the rear in case I can make it work) was not on the bike when the rear was crashed, and there are not supposed to be any problems with it.

Ok, different wheel, could be a different problem.

Sounds like the nipple is not accessible from the spoke side, and the shop that trued it used a screwdriver from the rim side.

No wonder they couldn't get the right amount of tension. It sound like the wheel is using Sapim hexagonal nipples. Here is a tool to tension such nipples:
http://www.starbike.com/php/product_info.php?lang=en&pid=10907

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Regards