andy_p

Once again I find myself stuck in the middle of another bicycle maintenance saga....

EDIT: I got myself a bit confused measuring things. This is now just a post about aluminium nipples being a bad idea....


I snapped a spoke on my MTB wheel (Bontrager Rhythm Elite 26", from 2009), and noticed the (aluminium) nipple had also cracked. I didn't think much of it, until I started truing the wheel - as soon as I touched one of the other original nipples with my spoke key, the square section would disintegrate! Obviously not happy about using the wheels again until I replaced all the nipples, I then hit on my next problem - the factory nipples have a very short section of thread from the seat in towards the hub, so the spokes also only have a very short section of thread. I can't find anything to replace them, so it's either new spokes, or getting lucky and finding a local with a threading machine...


and towards

Hoopdriver

10 mm of spoke threading is pretty standard. The unthreaded area at the bottom of the nipple is standard as well. It's not a surprise that aluminum nipples on a ten year old rim. Corrosion and metal fatigue take their toll. I'd recommend replacing all of the nipples as the old ones are clearly unreliable at this point. Chrome plated brass nipples will serve you well, unless you don't want to accept the small weight increase.

JohnDThompson 

+1.

tl;dr version: Aluminun nipples fail. Use brass, or expect to rebuild/replace your wheels every few years.

andy_p

EDIT: I had another think about this, and I was wrong about my measurements. However, I still need to replace the alu nipples, and I'm kinda stuffed because I only have 4mm of thread on the spoke. I either need to find someone with a threading machine, or buy new spokes

fietsbob

+ another one..

Cassave

Use washers under the nipple heads. That will move the nipple outward to the spoke end.

andy_p

What kind of washers will work? (This is a socketed rim) I guess they'd have to be pretty small. Do they just deform to match the shape of the seat?

Andrew R Stewart 

I've used tiny brass washers for this before. I don't remember the size spec but a simple nipple diameter measurement and a look up in a supplier's listing should get you the answer.

Question on nipple/spoke threading length issues. Where in relation to the nipple's big end did the spokes come to? It looks like the nipples are extra long at the big head end, as though to make using a nipple driver easier. Or is there a Nyloc insert in that big end?

I fully agree with doing away with alloy nipples and going to standard brass ones for just about any wheel, certainly any wheel you want to service after a few years. Andy

andy_p

Thanks for the info! I have to take up at least 1mm, so wasn't too sure about using washers. Yep, the original nipples have an extra long head with a hex end (and a nyloc insert), and the spokes protrude some way past the seat. I suppose that with a standard amount of spoke threading, you end up with not enough thread for a standard nipple. I found the DT Swiss Squorx nipple, which has a very similar design in brass, but it's expensive and hard to find, and still might not work.

nfmisso

Chrome plating is not done on brass nipples, they nickel plated.

Hoopdriver

Thanks for the correction. Another wrong assumption checked off my list.