Galvanic corrosion …..@#$%%

[Mongoose!]

I have these set of Mavic R sys wheels (ques it can be called vintage) that I want to rebuild on new rims

LBS managed to get all the carbon spokes loose on the front wheel and front wheel rebuild successfully.

They struggled with the rear wheel and was only able to get the carbon spokes on the non-drive side loose. As some might know, there wheels have aluminum spokes on the drive side on the rear wheel.

I believe galvanic corrosion might be the culprit

Does anybody maybe have a hack to   get these spoke nipples loose without damaging the spokes / rim or nipples.  

I don’t think the freezer trick will work as all materials involved are the same (aluminum)

Tried heating them up – did not work.

 *** Drain cleaner ??  ...  🤔

*** Pour Coke in the rim ?? (these rims have no spoke holes and coke will actually  stays inside the rim…)   .....   🤔

Thinking of cutting the rim to save the spokes, but it will be such a shame as they are undamaged.

Got my hands on a pair of black rims (new old stock) so that is the reason for the build.

Any advice will be appreciated - thanks

Edited September 14, 2025 by Mongoose!

[michaelbiker]

You can try dripping some baking soda solution on them to dissolve the aluminium oxide but be very careful. 

[Mongoose!]

Sadly the coke trick and drain cleaner trick dit not work😢

[BuffsVintageBikes]

I very much doubt anything will work in this instance, the surface area you're dealing with is very small so getting good penetration with any fluid is difficult. They often just snap when you apply too much force on them anyway.

[Mongoose!]

41 minutes ago, BuffsVintageBikes said:

I very much doubt anything will work in this instance, the surface area you're dealing with is very small so getting good penetration with any fluid is difficult. They often just snap when you apply too much force on them anyway.

Ag nee man  😭

[nick_the_wheelbuilder]

I have no solution for you, so I'm writing simply to offer commiserations...

Finding some NOS spokes and nipples may be your best bet.

[DieselnDust]

Galvanic corrosion only happens between dissimilar materials. 
min your case the spoke heads have galled in the nipples. The best thing you can try is get as much penetrating oil into the nipples and let them soak. Wet everything where the spoke enters the nippple and the nipple threads into the rim.

the rear wheel was always the problem with the R-Sys wheels due to it carrying the drive torque loads and more of the rider weight.

good luck

[droo]

1 hour ago, DieselnDust said:

Galvanic corrosion only happens between dissimilar materials. 
min your case the spoke heads have galled in the nipples. The best thing you can try is get as much penetrating oil into the nipples and let them soak. Wet everything where the spoke enters the nippple and the nipple threads into the rim.

the rear wheel was always the problem with the R-Sys wheels due to it carrying the drive torque loads and more of the rider weight.

good luck

If it is galling then the rim destruction technique should work by releasing the spoke tension, shouldn't it?

[DieselnDust]

3 hours ago, droo said:

If it is galling then the rim destruction technique should work by releasing the spoke tension, shouldn't it?

Wel yes but that might make it harder to remove the nipples 

if destroying the rim is an option then perhaps cutting it up midway between spokes and then soaking the rim /nipple /spoke interface in new engine oil for a few days. Then clamp in a vice and apply the spoke wrench and hope for the best 

I just figured that applying a lot of penetrating oil and the. Riding the wheel might work the oil into the nipples and this will allow the nipples to be removed 

Edited September 16, 2025 by DieselnDust

[SwissVan]

Mouse milk, even better than spook pee…… if you can find some

Muscle in a hustle... for speedy help in the removal of rusted and frozen studs. MOUSE MILK frees up cables, slides, linkages and bolts. MOUSE MILK is unequalled wherever a lubricant or penetrant is required.

MOUSE MILK will dissolve rust, relieve friction and resist oxidation.

MOUSE MILK has amazing creeping ability. Frozen nuts and bolts can be easily loosened and removed after allowing MOUSE MILK to creep down the threads and break up the rust and corrosion.

MOUSE MILK is an effective cutting fluid when drilling tapping or turning metals.

https://www.mousemilk.com

https://www.mousemilk.com/MM_Tech_Spec_rev1.pdf

Description

MouseMilk Penetrating Oil (Green) was

developed in 1968 and especially

formulated for the aerospace industry.

MouseMilk is composed of a series of

gum and resin solvents with overlapping

boiling points, compounded with a high

pressure- temperature lubricant. This

provides high penetration in hard to

reach places giving relief and

lubrication. MouseMilk will dissolve

rust, relieve friction and resist oxidation.
 

[no calves]

3 minutes ago, SwissVan said:

Mouse milk, even better than spook pee…… if you can find some

 

Muscle in a hustle... for speedy help in the removal of rusted and frozen studs. MOUSE MILK frees up cables, slides, linkages and bolts. MOUSE MILK is unequalled wherever a lubricant or penetrant is required.

MOUSE MILK will dissolve rust, relieve friction and resist oxidation.

MOUSE MILK has amazing creeping ability. Frozen nuts and bolts can be easily loosened and removed after allowing MOUSE MILK to creep down the threads and break up the rust and corrosion.

MOUSE MILK is an effective cutting fluid when drilling tapping or turning metals.

https://www.mousemilk.com

https://www.mousemilk.com/MM_Tech_Spec_rev1.pdf

Description

MouseMilk Penetrating Oil (Green) was

developed in 1968 and especially

formulated for the aerospace industry.

MouseMilk is composed of a series of

gum and resin solvents with overlapping

boiling points, compounded with a high

pressure- temperature lubricant. This

provides high penetration in hard to

reach places giving relief and

lubrication. MouseMilk will dissolve

rust, relieve friction and resist oxidation.
 

Had to double check the "legitness" of this with a name like that!

[droo]

17 minutes ago, DieselnDust said:

Wel yes but that might make it harder to remove the nipples 

if destroying the rim is an option then perhaps cutting it up midway between spokes and then soaking the rim /nipple /spoke interface in new engine oil for a few days. Then clamp in a vice and apply the spoke wrench and hope for the best 

I just figured that applying a lot of penetrating oil and the. Riding the wheel might work the oil into the nipples and this will allow the nipples to be removed 

The bench vise is a useful tool in this regard.

Rereading your post I see you were talking about nipple to spoke head galling, not the threads themselves. So your solution makes sense.

My standard solution for Mavic wheels with the silly spokes involves fire. But I've never been a fan of the system, so YMMV.

[DieselnDust]

5 minutes ago, droo said:

The bench vise is a useful tool in this regard.

Rereading your post I see you were talking about nipple to spoke head galling, not the threads themselves. So your solution makes sense.

My standard solution for Mavic wheels with the silly spokes involves fire. But I've never been a fan of the system, so YMMV.

 The nipples for those wheels shipped with so much thread lock on them that galling likely wouldn't occur nipple to rim, al least during the building phase.

But in use the rims flex so much that the nipple to rim interface would eventually displace the thread lock and replace it with Al oxide from both parts and that would gall. The nipples were also fragile so they're super easy to distort and then they're never coming out

[Mongoose!]

In this case the nipples actually move where in contact with rim but twisting the bladed spoke. So this means the corrosion is between the inside of the nipple and the aluminum spoke. We managed to get all the carbon spokes out. Problem is the rear wheel drive side aluminum spokes😢

[DieselnDust]

1 hour ago, Mongoose! said:

In this case the nipples actually move where in contact with rim but twisting the bladed spoke. So this means the corrosion is between the inside of the nipple and the aluminum spoke. We managed to get all the carbon spokes out. Problem is the rear wheel drive side aluminum spokes😢

yes so those are then galled. Heat isn't going to help here. You need to flush a lot of lubricant into the interface. Whatever you do DO NOT USE WEAK ACIDS LIKE VINEGAR OR HYDROCHLORIC ACID to dissolve the aluminium oxide. This will cause hydrogen embrittlement..

 

Here is an image of the spoke.

 

 

The white threaded bit is the thread lock material. The green bit is a plastic sleeve that's supposed to provide anti seize while the wheel is assembled. This plastic compresses and eventually falls apart and the ball head then galls in the socket inside the white threaded bit.

 

Sooooo your best bet is a lot of thin lubricant down the spoke so it soaks into the nipple and eventually allows the head to move inside that socket.

 

I know your spokes are the carbon version but those have a glass insulator at the bond interface to almost eliminate the galvanic corrosion. That the corrosion is not at the spoke/ threaded head interface tells me its galling .

 

Edited September 17, 2025 by DieselnDust

[Mongoose!]

2 hours ago, DieselnDust said:

yes so those are then galled. Heat isn't going to help here. You need to flush a lot of lubricant into the interface. Whatever you do DO NOT USE WEAK ACIDS LIKE VINEGAR OR HYDROCHLORIC ACID to dissolve the aluminium oxide. This will cause hydrogen embrittlement..

 

Here is an image of the spoke.

 

 

The white threaded bit is the thread lock material. The green bit is a plastic sleeve that's supposed to provide anti seize while the wheel is assembled. This plastic compresses and eventually falls apart and the ball head then galls in the socket inside the white threaded bit.

 

Sooooo your best bet is a lot of thin lubricant down the spoke so it soaks into the nipple and eventually allows the head to move inside that socket.

 

I know your spokes are the carbon version but those have a glass insulator at the bond interface to almost eliminate the galvanic corrosion. That the corrosion is not at the spoke/ threaded head interface tells me its galling .

 

Thanks so much for your valuable input.  Really appreciate.  Will go this weekend to my local Midas and see what kind of penetrating oil is locally available

Something like this?