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Corroded alloy nipples

3562 Views 6 Replies 6 Participants Last post by  Squash
I bought a new Scott Spark Ltd 10 weeks ago and this morning i noticed that one of the alloy nipples had snapped when i stripped the wheel done i noticed that alot of the nipples were corroded.

I know that they will corrode but 10 weeks?

Ive been running tubeless with stans and using CO2 to pump them up could this have anything todo with there premature failure?


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Check your other wheel

Go back to the place of purchase and get them working on the problem. This problem may be more widespread than just your situation. Getting the word out might save someone from harm.
Take it to the shop and see about warranty replacement.

But, you should not be using CO2 to pump up your tyres.

CO2 gas is slightly acidic, more importantly when mixed with water you get Carbonic Acid, which could corrode your wheels extra fast. Although it seems odd that it should get through a sealed tubless set up.
Good advice from Spade & Mike, but I can't help noting that neither Stan's nor CO2 should be in contact with your nipples unless there is a problem with your set-up, which should show up as relatively quick pressure loss.
Those spoke nipples are anodized, which is aluminum oxide. I think Stan's sealant has a little ammonia in it since it is a latex based product. Check the facts or ingredients on your Stan's can, if they list any as I don't have any personal experience with Stan's.
What I do know is ammonia and aluminum oxide don't play very well together. 10 days seams like a short time for this to happen, though.
Oops. Ten WEEKS. That time frame is more reasonable for something like this, if the mechanism I described above is in fact what is happening.
That is certainly corrosion damage...

and was most likely caused by CO2 and the amonia in the stans sealant. It most likely will not be covered under warranty. CO2, while an inert gas, certainly can be corrosive, as Fix the Spade noted. It is the main reason that CO2 tanks as used for paint ball markers an other applications, only have a 5 year life span without being tested to ensure the integrity of the tank. I've seen the inside of aluminum CO2 tanks that look just like that. Amonia will react similarly, but usually takes much longer. But what you end up with when you combine water, CO2 and amonina would likely be even more corrosive than plain carbonic acid. The fact that the CO2 and/or sealant actually got to the nipples indicates some flaw in your tubeless set up. I've been using alloy nipples on wheels set up tubeless with Stans sealant for quite some time and never noticed any corroding of the nipples.

In conclusion, yes the combination of CO2 and sealant likely had everything to do with the failure. That and the likelyhood that your tubeless set up allowed both gas and liquid leakage past the rim strip.


1. Stop using CO2 to inflate your tires. Not only does it produce the effects that you've already observed, it can make Stans sealant pretty much useless. Check the Stans website, they highly recommend against using CO2.

2. Double check your tubeless setup. Make sure that whatever you are using for a rim strip goes completely across the spoke bed from bead to bead and is completely sealing the spoke bed. Or use a sealant that does not contain amonia. Other options are to go to a full on UST wheel, or use the split inner tube "gehtto" system. Either would ensure complete seperation of the sealant form the spoke bed.

Good Dirt
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