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Corrosion or tubeless goo on XM819 rim?

1446 Views 8 Replies 5 Participants Last post by anotherbrian, Jul 26, 2010

anotherbrian

Discussion Starter · Jul 25, 2010

I was originally going to post this in Wheels and Tires, but I thought there's a better chance folks here will know if I have a corrosion issue or not.

I'm relacing a 5+ year old XM819 to a new hub.

All of the nipple cups have some degree of white build-up on the threads, as do all of the heads of the brass nipples. All but one of the nipple cups came out reasonably easy. One nipple cup felt like it was cross-threaded, though after dribbling a few drop of water onto the thread and working it back and forth it came out more easily (though still very tight) and its full threads were covered in the white.

Given the white stuff was on the heads of the nipples where there wouldn't be the same galvanic corrosion as between the nipple cups and the rim, I'm assuming it is dried up Stan's that leaked passed the valve stem. The nipple cups have been soaking in soapy water for more than an hour and the crud hasn't loosened enough to remove it with a toothbrush.

Should I keep soaking the cups in water, or is there something better? Should I find a stiffer brush (brass?) than a toothbrush or will it eventually loosen up? The threads in the rim also look gunked up, and I don't want to damage those (chase them using a nipple cup later?).

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anotherbrian

Discussion Starter · #2 · Jul 25, 2010

Mod please move to Wheels and Tires?

Could a moderator move this to Wheels and Tires? This was not a "general" question.

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shopcat_cycles

· #3 · Jul 26, 2010

Yes, general is the wrong place.

Photos would help with this. I'd be inclined to think corrosion given that you used stan's sealant, which is known to cause aluminum corrosion.

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shiggy

· #4 · Jul 26, 2010

anotherbrian said:
I was originally going to post this in Wheels and Tires, but I thought there's a better chance folks here will know if I have a corrosion issue or not.

I'm relacing a 5+ year old XM819 to a new hub.

All of the nipple cups have some degree of white build-up on the threads, as do all of the heads of the brass nipples. All but one of the nipple cups came out reasonably easy. One nipple cup felt like it was cross-threaded, though after dribbling a few drop of water onto the thread and working it back and forth it came out more easily (though still very tight) and its full threads were covered in the white.

Given the white stuff was on the heads of the nipples where there wouldn't be the same galvanic corrosion as between the nipple cups and the rim, I'm assuming it is dried up Stan's that leaked passed the valve stem. The nipple cups have been soaking in soapy water for more than an hour and the crud hasn't loosened enough to remove it with a toothbrush.

Should I keep soaking the cups in water, or is there something better? Should I find a stiffer brush (brass?) than a toothbrush or will it eventually loosen up? The threads in the rim also look gunked up, and I don't want to damage those (chase them using a nipple cup later?).

Since the rim and nipple cups are both aluminum, there would be no galvanic corrosion.

The build up on the nipples could be corrosion, could be spoke prep. Less likely to be sealant, as it would show up in other places inside the rim, too.

The nipple cups should have been installed with blue Loctite, which can turn white with age. I do not see a reason to remove it.

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deoreo

· #5 · Jul 26, 2010

anotherbrian said:
I'm assuming it is dried up Stan's that leaked passed the valve stem.

Did you ever ride this wheelset across a shallow stream or creek crossing?
Maybe in the rain, or through a mud puddle?

That water will get into the spoke cups from the spoke side, just like it will get into the
spoke holes on a normal rim.

Somehow I don't see this as a sealant problem, just a thought.

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anotherbrian

Discussion Starter · #6 · Jul 26, 2010

Shiggy, could you move the thread to Wheels and Tires please?

= = =

The wheel was built by Speedgoat in early 2005. If this is dried up Loctite or spoke prep, they used a whole lot of it and got it to places I would have thought were impossible (see pics below).

The wheels have certainly been immersed in water.

The valve stems have come out a number of times when I had to put a tube in on the trail. Once I had goo sputter out at a nipple when I didn't completely clean the dried up residue off the valve stem during reinstallation, so I do know goo has gotten inside the rim though I don't think it was a tremendous amount.

After soaking for 18 hours in soapy water, the crud hasn't loosened. Scratching it with my finger nail takes off the paint/plating on the head of the nipples, but doesn't do a whole lot on the cups. I've tried soaking a few of the cups in gasoline and after an hour it is softening.

The threads in the rim are in the same condition as the threads on the cups. Lots of white powder is floating around inside the rim as well as a result of removing the cups.

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shiggy

· #7 · Jul 26, 2010

anotherbrian said:
Shiggy, could you move the thread to Wheels and Tires please?

= = =

The wheel was built by Speedgoat in early 2005. If this is dried up Loctite or spoke prep, they used a whole lot of it and got it to places I would have thought were impossible (see pics below).

The wheels have certainly been immersed in water.

The valve stems have come out a number of times when I had to put a tube in on the trail. Once I had goo sputter out at a nipple when I didn't completely clean the dried up residue off the valve stem during reinstallation, so I do know goo has gotten inside the rim though I don't think it was a tremendous amount.

After soaking for 18 hours in soapy water, the crud hasn't loosened. Scratching it with my finger nail takes off the paint/plating on the head of the nipples, but doesn't do a whole lot on the cups. I've tried soaking a few of the cups in gasoline and after an hour it is softening.

The threads in the rim are in the same condition as the threads on the cups. Lots of white powder is floating around inside the rim as well as a result of removing the cups.

Well, that is much more extensive than what I read in your OP. Pics and relevant details always help get straight to the point.

I would not reuse the rim in the first place.

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jeffscott

· #8 · Jul 26, 2010

Geez i have had that type of build-up...

Salt from the road in winter....

Could also be from salt water or hard water...

Try soaking in a dilute solution of CLR....that will probably cut it, and that would mean Ca or Mg...

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anotherbrian

Discussion Starter · #9 · Jul 26, 2010

Thanks for the move.

The wheels have never seen salt water or salty air. Any dips/immersions are in the seasonal creeks in the Sierra's, and I try to avoid those as much as I can to keep my feet dry.

I was going to try brake cleaner next, then carb cleaner after that. I'm not sure if we have any CLR, but I'll try vinegar on one right now and see if it has any effect.

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