On Monday, August 17, 2020 at 2:36:12 AM UTC-7, Sock Puppet wrote:
On 16/08/2020 19:01, AMuzi wrote:
On 8/16/2020 8:58 AM, Sock Puppet wrote:
I have a cheap adventure bike, just over a couple of years old.

After about a year the back wheel spokes started breaking,
so I rebuilt it in January with cheap 10 GBP spokes off
ebay. Now after only 5000km I've had a couple of spokes go
again, from fatigue.

I'm surprised the spokes would go so quickly. Is it likely
that buying bargain basement spokes was a dumb thing to do
and I should have bought more expensive double butted
spokes. Or is it possible there is something wrong with the
rim or hub.

So now I'm thinking of rebuilding again with better spokes
and a new hub (needed anyway). Would I be better buying a
new wheel? This is my first disk brake bike, I assume the
rims are effectively immortal.



The differences between the worst spokes available and the best is a
much smaller range than a hasty sloppy build vs a careful job.


Yeah, you are probably right. I hadn't built a wheel for 15 years. I
just seem to remember double butted spokes being much more reliable.
Maybe, more forgiving of a crap workman.

Did you lubricate your nipple threads? With what?Â* Are you using regular
plated brass nipples or those demon droppings in aluminum? Did you build
with drive spokes inside? How many spokes and what cross pattern?


Lubricant standard lithium grease, steel nipples, 32 spokes, 3 cross.

Did you observe the rim manufacturer's tension specification?


lol! no. I assumed rim manufacturers specs where a maximum, above which
you might rip through the eyelet.

To back up a bit, yes you can have problems with rims, hubs and spokes. I've had all of those, although the spoke issue was well known and design specific (elongated DT J-bends and way back in the early '70s and prior, just crappy spokes). I've had OE wheels with rims that were nipple lathes, but then you get broken nipples and not broken spokes, and those OE wheels usually have aluminum nipples that are prone to breaking anyway. If you have plated brass nipples, that typically will not happen. You can have hub flanges that are too thin or that have sharp holes or other problems -- but assuming proper thickness, most flanges are made out of aluminum and will take a proper shape. Straight gauge and DB are both reliable if well made, and the benefit of DB is lower weight and higher elasticity so the spoke stretches more at the same tension making it less likely to go slack when loaded/compressed. These days, you have to go to really cheap off-brands to get spoke breakage on a well built wheel -- but it can happen. And with enough fatigue, you can break the best spokes.

-- Jay Beattie.