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Discussion Starter · #1 ·
I bought some Ibis factory $500 wheels that come, it turns out, with (black) aluminum spoke nipples.

Why anyone would choose to use aluminum spoke nipples, especially when they aren't anodized some blingy color, is beyond me. But use them they did. Brass is less likely to fracture, and has the additional merit of being more forgiving if the spokes are slightly too short (again, WTF Ibis/).

First the ones in the front wheel started to fail. After the second one failed, I had the wheel re-built with brass spoke nipples, and it has been fine since.

Now the back one has started to do the same. Walked into the garage, tire was flat. Spoke nipple was broken.

I'm using Orange sealant. Is it ammonia-free? (Ammonia can accelerate the corrosion of aluminum).

This has put me off ever buying anything from Ibis, which is too bad because it is a great local (?) company and makes some nice bikes.

I've never had this happen with any other wheel-set, regardless of how cheap or expensive. What all the others have in common are brass nipples.
 

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Elitest thrill junkie
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Assuming these are not CF rims? It sounds more like the main problem is the spokes are too short? While I find alloy spokes with CF rims to be a time-limited situation, it depends on the environment and many factors as to how long you'll get out of them, but short spokes, yeah, those will generally give out pretty early with alloy nipples.
 
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Discussion Starter · #4 ·
I suspect Ibis specced spokes that are too short, but if so, they managed to do it on both front and back wheels. Also I don't see exposed threads on the spokes, so if they are too short, it is only by a tiny increment.

The rims are indeed aluminum.

The wheels (and bike) are rather under-used. It is my bikepacking bike, and I haven't used it much at all since SARS-CoV-2 (or even much before that). All three nipples spontaneously broke while sitting in my garage.

I suspect it is helped along a bit by ammonia gas liberated from the sealant.
 

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Elitest thrill junkie
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You gotta pull tape and look at the underside of the nipples to see where the spoke threads are. If they are flush or extending a little, usually fine. If they are short by a few mm, bad.
 
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Elitest thrill junkie
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I have a set of 738s I purchased about five years ago as a takeoff. After about a year a nipple cracked on the front wheel. I replaced it and happened to see the Ibis rep at a demo day and mentioned it. He told me they had a batch of wheels where they were built by the supplier with the wrong spoke length. Knowing I bought the wheels second hand he still had a replacement wheel sent to my LBS to replace the one I had.

I don't know how old the wheels are or if they are the older 38 series or newer S35, but I would reach out to Ibis before simply declaring them junk.

For the wheel builds I do, I always use aluminum nipples and have had no problems, but pay careful attention to spoke length and that the spoke clears the nipple bed. I use brass on my DH wheels, not because it is stronger, but cheaper and the weight doesn't matter.

You can easily check to see if the spokes are too short by pulling the rim tape and looking to see if the spokes reach the bottom of the slot in the nipples.
 
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Discussion Starter · #14 · (Edited)
Thanks for mentioning that.

These are 738s I bought a few years ago for a project build (Advocate Seldom Seen -- thread is around somewhere).

I am glad to know there is likely a rational reason for this happening.

I haven't taken it apart yet to look but will. At this point I would be surprised if they weren't too short, especially given that it is a known issue.

BTW I wasn't going to junk them. I was going to replace the nipples (as I did with the front wheel), but now maybe both the nipples and spokes (unless Ibis has a better idea).

Again, @Cary thanks!
 

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Discussion Starter · #15 ·
Ibis never got back to me. The back wheel started to do the same, so had it rebuilt with brass nipples as well.

I think for now on it will be boutique over-priced hand-built brass nipple wheels for me. The original price plus the rebuilds is now approaching the price of my aluminum Chris King wheel-set.
 
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