Bought a Specialized Camber a couple of years ago. Rode in the rain. Aluminium nipple heads started shearing off ever second ride. Had wheel rebuilt with brass nipples. Apparently very common problem in Sydney. Why?

Views: 283

Comment by Neil Alexander on October 6, 2016 at 7:41am

Correlation does not imply causation...

Could be over-tensioned wheel?

Comment by Donald Rintoule on October 10, 2016 at 11:02pm
No nipple heads are corroded
Comment by AdamM on October 11, 2016 at 9:22am

My guess would be that Sydney is a coastal city and the salt air doesn't do the nipples any good.

Comment by Neil Alexander on October 11, 2016 at 9:32am

@DonaldRintoule

I am guessing you mean "No, nipple heads are corroded." As opposed to: "none of the nipple heads is corroded". Punctuation is important!

So, wheel NOT overtensioned, then. OK.

–Ed

Comment by Jon on October 15, 2016 at 2:13pm

Aluminium really is a poor material. It is soft, cold flows/ creeps and is damaged easily. If you put a thread in aluminium, it will only really hold once, and repeated adjustments or undoing and re-tightening will strip the thread entirely. A spoke nipple's entire job is pretty much to be a thread. So aluminium is really a poor choice unless you're willing to inspect and replace on a repeated fashion. Which is totally fine for the racers here.

Aluminium is also really reactive. Sure, it creates a stable oxide layer, but if that layer doesn't form for some reason, it won't last long. The textbook example of this is where some genius puts a stainless steel bolt into aluminium at the sea side.

Most aluminium corrosion that I’ve come across on bike wheels (which don't live near the ocean) is often caused by tyre fitting and washing agents. I think it's the caustic that does it from memory. For rims, it is usually not significant as they are thicker.

I assume it's an aluminium rim? does it have eyelets on the spoke holes?

Comment by Tim on October 22, 2016 at 9:31am

I have a Camber too, and once when I give the bike a good hit, it was a nipple that broke not the spoke.  Obviously the nipple is the weakest part of the chain.  Not such a bad thing, easier to replace a nipple than a spoke, especially on the rear wheel.

Comment by Donald Rintoule on October 24, 2016 at 6:53am

Agree not breaking a spoke is a good thing but when tubeless changing nipples every second ride is a pain. Wheels rebuilt with brass nipples now seem stiffer. When cycling in southern highlands for two days Wingello and Welby and had a faultless time. Wingello single tracks have s a brilliant flow - way better than Bantry Bay!

Comment by AdamM on October 24, 2016 at 9:56am

Two Camber bikes breaking nipples? I wonder if Specialized specified slightly too short spokes for those wheels? Alumnium nipples really do need the spoke to extend all the way through to the outside of the nipple to maximise their longevity. If the spoke is a mm or two too short the spoke fatigues much more quickly, which might lead to the breaks we are seeing here, regardless of corrosion.

Comment by Donald Rintoule on October 24, 2016 at 11:41am

Thinking back you could be right on this. I don't recall any spokes past the top of the nipples or even really level with their top. Also living on the Northern Beaches, the salt might have had a part in their corrosion.

Comment by AdamM on October 24, 2016 at 12:02pm

I have a friend who rides VERY high end components on his MTBs, and builds all of his own wheels. He has successfully used aluminium nipples for at least a decade, even in Scotland with their salted winter roads, but he is fastidious in his wheel building and the spokes always extend to the top of the nipples. It plays a big part in reducing any shear loads on the nipples themselves.

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