Abe_Froman

So, I have a set of wheels, double walled alex rims, 36 spoke, 700c rim. Mileage on them is somewhere between 5000-10000. I have not had any trouble with them in 5 years, now 2 broken spokes in ablut 100 miles.

Both non drive side, both broke off at the nipple. I guess my question is, how worried should I be? I picked up a spoke at yhe local bike how to just throw on and see what happens, but I would like to know that this wheel is solid. It's on my regular commuter/longer distance rider, so if multiple spokes pop I'll either be late or stranded likely pretty far away from home.

So, recommendations? I'm considering:

New wheel
Replace spoke and pray
Handbuilt wheel from bike shop
Rebuild existing wheel myself with new spokes (I've never built a wheel...)

TimothyH

Others more experienced than I can probably say with more certainty but I don't think a couple of broken spokes is a reason to replace the wheels.

I recommend prayer whether you replace the spoke or not.


-Tim-

Andrew R Stewart 

Well not sure I agree with Tim. But the only test that counts is your future experience. There is a value to peace of mind. After a few spoke repairs the cost of a new wheel is already been had... Andy.

Abe_Froman

Well I'm replacing them myself so the cost there is negligable. And I'd really hate to scrap the whole wheel as I just replaced the bearings and regreased, but I would if the consensus is the wheel has just reached 'old age.'

Andrew R Stewart 

So self repair does shift the equation a bit but at the bottom line is the reliability of the wheel when you're riding it. At some point that threat will be greater then your cost to replace. Only you can make that value judgment. Andy.

Bill Kapaun

The analogy FBinNY uses is that spokes are like popcorn. After 2 or 3, they increase in frequency.

I guess the cheapest way would be replace NDS spokes only. Using new nipples will save many times their cost in frustration.

dsbrantjr

New BRASS nipples especially so.

Abe_Froman

I was sort of hoping I could shrugnoff the responsibility of decision making onto others. Oh well lol.

I guess I'll replace the spoke and hope for the best. If I pop another one...I'll just switch to winter bike a bit early and rebuild the wheel at my leisure.

FBinNY 

I don't count a set number of broken spokes per se, but I look closely at the amount of time between breaks and by how much it's diminishing.

I like to think of spoke breakage as being like making popcorn. First you get one early pop, then a second, and soon things are happening faster until the entire mass seems to be popping at once.

So, you need to decide whether you're still at the early bird stage, or if things are about to happen faster.

Part of this has to be consequences. How bad does the wheel go out when a spoke breaks, and can you still ride either bt opening the brake release, or maybe a quick true job to get it rideable. Then how badly are you inconvenienced. My commute used to be six miles, so if the west thing happened at exactly midpoint, I'd be looking at a 3 mile walk at worst. That's fine and I'm willing to accept that, but if this were my touring or sport bike, I'd be much more concerned because 50 miles or more is a pretty long walk.

CliffordK

Fortunately NDS spokes are the easiest to replace on the road, so you could bring a spare spoke or two with you. Also pack a spoke wrench to true the wheel to 35 spokes. Easy to do, but a pain to undo.

But, the question is why you're breaking spokes at the nipples, and why on the NDS side.

The angle of the spokes are slightly greater on the NDS side than on the DS side. I'd look at the remaining spokes carefully and see if there is a bend right at the spoke nipple (slight?)

It is possible the wheel was assembled backwards. I.E. The spoke holes have a R/L orientation (generally same for both sides). If you put a Right spoke/nipple into a left hole, then you put stress at the nipple.

Also, I've read that low spoke tension is as bad as high spoke tension.

As far as rebuilding the wheels... if you can true the wheel, you can rebuild it. It just takes lots of patience.

Make the brake track is very good. No sense in spending a few hours rebuilding a wheel with a worn out rim.

TimothyH

This is what I was getting at in post number 2.

Why do the rim and hub have to be replaced if spokes are breaking? Can't the OP just take the wheels in for service?

I took old Ksyrium SL's to ProWheelBuilder.com. He replaced two spokes, loosened all the others, cleaned, tensioned, trued, etc, all for $55. As long as the brake track has life in it, why can't the OP do the same, take it to a good wheel builder in Chicago and have it serviced for a couple of bucks?

Asking out of ignorance. Not trying to challenge.


-Tim-

cyccommute 

I would agree if the spoke had been the part that broke. However, for a spoke nipple break which is extremely rare, I wouldn't be that concerned about the overall strength of the wheel. I would suspect that the nipples are aluminum and the spokes aren't long enough to be buried all the way into the nipple. Detensioning the wheel and replacing the spokes with brass ones should fix the problem without a complete rebuild.

Abe_Froman

No no...the nipples are fine, the spoke is what broke.

cyccommute 

I'm still not convinced that the wheel is "bad". Spoke breakage at the nipple is rare and not indicative of the same problem as the spoke breaking at the elbow is. Two breaking is extremely rare and might warrant watching the wheel but simply replacing the broken spokes is a good course of action.

That said, if you break more spokes at the nipple, it may be a materials issue...i.e. poor manufacturing of the spokes...rather than a mechanical issue like broken spokes from over- or under-tensioning.

Bill Kapaun

He stated they have 5-10k miles on them.
I'd expect the spokes are simply dying.

FBinNY 

Of course this may be a case where the OP describes the issue poorly, but he twice referenced SPOKES breaking at the nipple, not the nipple breaking.

So, most likely it's a case of fatigue failure at the first thread. This can happen either when there's misalignment, or when the nipple is held very rigidly in the rim and the spokes are flexing relative to the nipples as opposed to taking the nipples with them.

Elsewhere you mentioned the issue of spokes being short and not reaching fully into the nipples. This is the leading cause of nipple failure, and easily confirmed by looking at the broken end, or by removing the tire and looking at the tops of the nipples.

nfmisso

Each of us has a rule of thumb, from casual observation, it seems to make a big difference if we build our own, or pay to have someone else do it.

My rule: one breaks - replace one, two break - replace all. But I build and service my own wheels. BEFORE replacing any spokes, the rim needs to be checked for brake track wear and spoke hole cracking. The hub also needs to be checked - bearings, cups, cones and spoke holes. There is no addition labor in replacing a rim (and/or a hub) when replacing all of the spokes. Even though I build my own wheels, my time is very valuable to me.

Given the number of miles on the OP's wheels, I would probably do a complete check out of the rim and hub, and if good, replace the spokes and nipples.

Abe_Froman

I actually replaced the bearings and regreased the hub when I replaced the first spoke.

I'm thinking the wheel is actually a bit undertensioned and the spokes are fatigue breaks. I picked up a used Park Tool tensionometer a while back from my bike store that I used to check spoke tension at the time of the first spoke break. At the time I just went by the bike shop comment of "spokes should be 20-25" on the tensionometer. Since then, I've done some research and am thinking that In reality tension has been on the low side, a fairly consistent ~100kg, even though it was in the middle of the very broad range given by the bike store.

So now my plan is to replace spoke, retension drive side spokes to 120kg, and make necessary tension adjustment to non drive side spokes, and hope the spokes are not overly fatigued already.

cyccommute 

That's hardly high mileage on the wheels. While I don't agree with many that spokes have a nearly infinite life, they should be be able to handle mileages several times higher than 5K to 10K miles.

Bill Kapaun

We have no idea of the build quality. If typical machine built wheels.......

veloz

I've broken multiples on several wheel sets. Because money was short, I replaced them and rode thousands of miles further. If you're running 36h I doubt you'll ever get stranded. Plan B: If no cracks in the rims, replacing spokes is a good off season project.

Abe_Froman

So anywho... a short update. Replaced the broken spoke again, and checked tension on the spokes. The tension was around 100kgF drive side, and 70KgF non-drive. Dish was off center a few millimeters to the non drive side as well. I'm assuming these issues combined would make it not surprising to pop a few spokes after thousands of miles. I tensioned the drive side up to about 130 KgF, and improved the dish just a smidge...it's still off maybe 2mm from center now. I still need to do a bit of truing though so maybe I can get it closer. I'm assuming a mm or 2 won't be a big deal if the wheel is tensioned properly.

On a side note....I just had a light bulb go off in my head as I was contemplating whether it would be worth it to pick up a used truing stand at my LBS. I can just use my indoor trainer with an adjustable roller! I can use the roller itself to measure roundness, and just lean a piece of wood or something against the roller to measure lateral trueness.

davidad

40k miles is old age. Sounds like the spoke tension needs to be raised. Start on the drive side and then recenter the rim. This also raises the NDS tension.
Carry a few extra spokes on the bike just in case.

davidad

Good quality spokes never die. If they are not kinked they can be reused indefinitely.

davidad

What brand of spoke is in the wheel? There should be an identifying mark on the spoke head.