Rusty Nipples (ok corroded, but where's the drama in that?!)

[alvintc]

OK - So I have everyones attention now.

pretty much all the spoke nipples on my wheels have corroded. The wheels are Mavic Aksiums as came fitted to my Cannondale SuperX Hi-Mod.

The bike is only 4 months old & cleaned regularly so this was a bit of a shock. Found it when I couldn't tighten a couple of spokes.

So the question - is this normal? How can I prevent this, I'm not really looking for new wheels as everything else is working great for me.

 

[Yellow Saddle]

Yes it is perfectly normal and it can be prevented by...ahem....not being a weight weenie.

Aluminium nipples corrode readily and are rubbish. Brass nipples don't corrode and live forever. Unfortunately bass nipples weigh 12 grams or so more than aluminium nipples and since the primary criteria for choosing wheels is weight, the manufacturers are between a rock and a hard place and choose the hard place - lightweight nipples.

Your symptoms are spot-on. Corroded nipples present as frozen nipples. If you force them they usually split or shear off right below the spanner square.

The mechanism by which this happens is the aluminium oxide molecule that's twice as large as the aluminium molecule it is seeded from. The thread hole literally shrinks violently.

Replace them with brass nipples, go for a ride, have a beer and never worry about nipples again.

 

[accountantpete]

This has come up before https://www.cyclechat.net/threads/mavic-aksium.144410/

It's either because of corrosion or Mavic use "self-locking" nipples ie with some sort of threadlock applied.

If it is the latter then you have to apply quite a bit of force to turn the nipple and when it moves it will usually issue such a loud 'crack' that you think the frame has just broke in two ( always loosen the spoke one turn first and then tighten 1 1/2 turns if you need to tighten the spoke so you are not trying to break the threadlock and tightening up in one go).

 

[Yellow Saddle]

Useful info from @accountantpete Alumunium corrosion is easy to spot. White grainy crystals like fine table salt will be present on the bare aluminium parts (i.e. inside the hole and spilling out) rather than on the anodized (coloured) bits of the nipple.
Threadlock compounds are usually some form of anaerobic sticky glue which can be softened by applying heat. Even a hairdryer will produce enough heat to help with all but the strongest threadlock. Pete, I understand that the "crack" method will work but sometimes the nipple will give before it loosens and then you have a double problem. Threadlock on nipples is evil, but that's for another discussion.

 

[alvintc]

Ok - this could actually be the issue rather than corrosion! There's definitely thread lock in there - bright blue.

Asking the silly question - what can I use to hold the nipple while turning the spoke nut? I assume there's something akin to a nipple socket but no idea what size & everthing I read says they take a normal flat head screwdriver, they definitely do not!

 

[Yellow Saddle]

Ok - this could actually be the issue rather than corrosion! There's definitely thread lock in there - bright blue.

Asking the silly question - what can I use to hold the nipple while turning the spoke nut? I assume there's something akin to a nipple socket but no idea what size & everthing I read says they take a normal flat head screwdriver, they definitely do not!

Blue is definitely the threadlock.

Spoke nut and nipple is one and the same thing. The nipple screws directly onto the spoke and you need a dedicated spoke spanner that connects the square on 3 1/2 sides. Do NOT attempt using a shifting spanner or pliers. Nipples come in 3.2mm, 3.4mm and other weird sizes. The screw slot is in line with the spoke and accessible from the tyre side via holes in the rim. It may not be successful from there but try, if you strip the slot, you still have the square side. Do heat the nipple either with a heat gun or perhaps soldering iron.
You may have to old the spoke as well. If it is a round spoke don't try. If it is a flat spoke you could use any slotted instrument like a piece of wood or preferable strong plastic.

 

[alvintc]

Many thanks again for the help.

Using a spoke wrench just has the nut spinning (the spokes on mine are free to rotate at the hub end - straight pull spokes?). There's definitely not a screw slot visible, had the tyre & rim tape off the other day and it's not visibile on any of the nipples.

Unfortunately round spokes on this one so it looks like I'm limited on options!

 

[Yellow Saddle]

Many thanks again for the help.

Using a spoke wrench just has the nut spinning (the spokes on mine are free to rotate at the hub end - straight pull spokes?). There's definitely not a screw slot visible, had the tyre & rim tape off the other day and it's not visibile on any of the nipples.

Unfortunately round spokes on this one so it looks like I'm limited on options!

I can't picture the nipple here. Picture?

 

[alvintc]

I can't picture the nipple here. Picture?

I'll try & get some tonight, but it looks a lot like this:

 

[Yellow Saddle]

OK, it seems as if the spoke (everything black) is a simple straight-pull spoke. See it as a long bolt. The silver bit is the nipple. The nipple is the "nut"

The nipple screws onto the spoke with standard right-hand thread. Righty tightly, lefty loosy. As you say, the nipple hasn't got a screw slot but luckily for you a more secure hex head. Probably 6mm hex. You need a thin-walled socket driver for that.

You have to hold the spoke when turning, otherwise it will just spin, as you say. You can prevent it from turning using pliers but try not to scratch the spoke. Scratches beyond the black or more than cosmetic, they cause weakness. The blue b.t.w. is nylon, so don't heat it. It is a so-called nylock nut.

 

[lpretro1]

There is a special little tool available for holding Mavic spokes

 

[Yellow Saddle]

There is a special little tool available for holding Mavic spokes

Yeah, a piece of plastic with a slot in it. A piece of screwdriver handle-like plastic with a hacksaw blade slot in it will do for a once-off DIY job.

 

[alvintc]

You guys are awesome.... So where to get something small enough to hold my nipples? Or the mavic tool/ thin walled socket if we're being grown ups

 

[Yellow Saddle]

You guys are awesome.... So where to get something small enough to hold my nipples? Or the mavic tool/ thin walled socket if we're being grown ups

Professional bike tool suppliers have such tools but you can get one from a good hardware shop. Ask for a socket driver in the relevant size. This will be either like a screwdriver with a socket in line or like one of those T-drivers with a T-handle. The trick is to get one thin enough. Thus, you need to know

a) the size of the hex (I'm guessing 6mm but guesses are dangerous)
b) the diameter of the hole in the rim. This you need to assure that the socket will fit into the hole. Space is limited.

To hold the spoke, just use pliers for now but be gentle. Actually, even a small shifting spanner will work.

 

[Ajax Bay]

Now that you've bottomed out the OP's solution/options, please can you share your insights into 'evil'.

Threadlock on nipples is evil, but that's for another discussion.

Why would wheel builders do that? Is there any risk spokes will spontaneously loosen? The challenge the OP has had, given his spokes are straight pull, makes it seem particularly unwise in such spoke design.