nipple pull through rim failure
 

Bike Gurus,

I have a specialized crosstrail with the stock alexrims, CT 700's. Owned and ridden almost every day for about 2 + years, mostly on Berkeley and Oakland city streets. Can't say enough about how great the bike has been. Now I am experiencing rear rim failure. Specifically the spoke nipples are starting to pull through on the back rim. I have never experienced this type of problem before and am turning to the community for advice.

Given the research I have done, I know it's a potentially dangerous situation so I am retiring the rim & planning on building a new one with my existing freewheel and cassette. I have also heard that purchasing a rim with "one-piece, double wall steel eyelets" will help prevent this sort of failure.

I ride a lot, 8 miles 5 days a week but not real hard, curbs occasionally, and the inevitable pothole & am looking for suggestions on what to replace this rim with, that will last me more than this one has.

Cheers,
Mike

Attachment 137569

Thats pretty bad. When you rebuild make sure spoke tension is right. Over tightening could cause that kind of failure.

I think the failure is more likely from impact with chug holes, curbs, etc. Double wall rims would be better.
Also be sure to inflate the tires before each ride.

@DOS & Al1943
I had the wheel trued a couple of times at my LBS and they failed to mention the failures, the one pictured is the worst & I have about 6 more minor ones. They are double walled rims & while not religiously checking my tire pressure I do check it about once a week.

I wore out a pair of armadillo tires before this started to happen.

Double wall rims would only be more resistant if they had a "double eyelet" which transferred some of the forces to the other wall, otherwise the spoke would be pulling on the same (though now possibly thinner) inner wall.

BTW this has become a more common type of failure because today's high dish wheels require so much tension on the right spokes. Using double butted spokes will help, and so will using lighter gauge spokes on the left flange to offset some of the tension differential.

What led to this particular failure, could be anything from it simply being it's time, to a prior re-alignment causing excess tension on the one spoke. But you're right, the rim is toast. Not to start a huge debate because there's legitimate differences of opinion, but I'd replace the spokes and nipples as well.

you have either a freewheel or a cassette on your wheel.

yes a better quality double wall rim with double eyelets is much better, be cause the eyelets help distribute the load over a larger area of the rims, and of course a rim of that type is just a bettter quality rim

I was about to say 8mi 5 days a week was not alot until you said you wore out a pair of tires, that is alot of miles but a rim should last a bit longer.

if you have 6 cracks like this you should have noticed them before the LBS. if you ride/commute everyday you should be at the very least looking over you bike onece a week. I give my bikes a quick walk around every time I ride.

Do you have a reciept for the truing? It looks to me that they might have overtightened the spokes. Are the spokes still tight? I never trust the LBS and if they ever work on your bike keep the receipt in case they mess it up.

On the rebuild- if your streets are bad then you definately should build up a stronger rim. Id recommend a rim with eyelettes-just about all rims with eyelettes are double walled, but check the ones you want to buy to make sure. Make sure you have a 3 cross lace pattern too, the tension on a 3 cross is not nearly as high as spokes with 1-2 cross or radial lacing.

You haven't said what size tires or how much pressure but for most road bikes with narrow tires you really need to pump them up before each ride.
I doubt that the spokes had too much tension. Unless the rims are really crappy they should be able to take more tension than the shop mechanics can put on the spokes.
Double butted spokes probably would have helped.

Sooprvylyn....if you are going to comment on stuff like this - in lieu of actual wheelbuilding - at least read up in depth and in detail...otherwise don't...


...anyhew...


The described symptoms usually are the result of 1 or a combination of the following:

1. Lotsa miles...
2. Lotsa direct and instantaneous torque/power being driven and released into the wheel.
3. Bigger riders...

More often than not when one of my rims return with the same thing (double-wall non-eyeleted rim) it's a customer who is in the 200+ lbs. range with an attitude:

"Ha! There's hill! And here's a badass!"

...who then proceeds to hammer sitting or standing with pedal strokes that probably make the frame cry.

Heavier rim is not automatcially called for - but moving up to double-eyelets is definitely a helpful upgrade.

If my Taiwan generics don't have the option available - it's typically a move to a double-wall double-eyelet Alex, DT, Mavic or Sun rim.

Even then you are still crossing your finger cause some riders can really drive an awful lot of torque into a wheel that'll make just about any rim do this - even with double-eyelets.

I envy them really...

:D

Unless the failure was immediately after an alignment, it it isn't reasonable to blame the shop. Rims do fail, that's a simple fact of life.

Eyelets help somewhat, by spreading the forces over slightly more area than the nipple head. Single walled rims come both with and without eyelets, double walled rims come with no eyelets, single eyelets, or double eyelets.

As I said earlier, there's no way to know the proximate cause of the OP's problem. He can spend more for a better rim, but better in the rim world often means lighter, not stronger. In any case 2 years, isn't terrible life depending on conditions, and if he sinks more dough into a wheel up front, there's no assurance that it won't find a pothole, or trolley track and die a premature death anyway.

My recommendation is that he ask around to find a local wheel builder of good repute, and follow his advice rather than try to digest the conflicting advice he'll get on the forums. For my part, when clients come to me to have wheels built, then proceed to tell me how, I decline the work.

I didn't mean to insinuate that the shop is definately to blame. But if the problem arose within a few days of the truing then, yes the bike shop could be to blame. Keep your receipts, there are a lot of Hack mechanics in bike shops, and unless you can tell the good from the bad you better keep your receipts. That is all I meant. Anyone who disagrees with this statement lives in a fantasy world where everyone is good at their job.

yes a heavier rider causes more stress on the rims, especially if he cranks up steep hills without even pedal pressure. A heavier rider should have beefier wheels, both the rims and the number of spokes play a part here.

Yes rims wear out. and 2 years on these stock alex rims aint bad.

Yes bad roads and potholes can f up a rim- a beefier rim will help here too.

that being said, I still recommend a double walled rim with eyelettes on the rebuild, unless you are a weight weenie and dont mind replacing your rims every couple of years.


If you do decide to go to a shop, ask around and see which one has a reputation for good wheel builds. And keep your receipts!

Quotes:


"Make sure you have a 3 cross lace pattern too, the tension on a 3 cross is not nearly as high as spokes with 1-2 cross or radial lacing."

[Are you talking tension measured by deflection per distance - or "feel"]


"especially if he cranks up steep hills without even pedal pressure."

[Wasn't aware that uneven pedal pressure is able to discriminate during its input spoke by spoke to an independent circular rotating object.]


"I still recommend a double walled rim with eyelettes on the rebuild, unless you are a weight weenie and dont mind replacing your rims every couple of years."

[Wasn't aware that DT 1.1's and Mavic Open Pros were tanks...]


=8-)

MrRabbit,
You are a D!ck. =8-)
hope you feel better about yourself now.

This thread makes my head explode

1) Determine average reading of spoke tension on drive side right/front wheel
2) How much higher than normal is it, on average?
3) You can't blame the shop for truing a wheel. Unless they did such a ****ty job that they also brought up the tension on the wheel as a whole
4) Crappy rims will fail like that, alex CT700's are spec'ed OEM because they're cheap and they suck

I can't tell you how many people I've met who did just that, even shop employees. Their logic was the wheel must have lost spoke tension over time, so they only tighten spokes when truing and never loosen.

Soop: Still, I agree with Operator that you can't blame the shop unless you could prove such a case. I don't see where MrRabbit was being a d*ck. Just disagreeing, and rightfully so.

I have the receipts from my last couple of spoke replacements and wheel truing but don't plan on going back it would be too difficult to prove that the shop messed up & I agree that a couple of years on these rims is what it is given the type of riding I do. S

I'll be picking out a better (not lighter...) double wall with double eyelets.



Thanks for your responses, I know enough about this stuff to be dangerous & getting this kind of feedback is great for me. I appreciate everyone's input.

In the 700c range that can take a 28 through 45mm tire I would recommend to Mavic A719. I have a pair right now i built last year and they are quite nice. Double walled, eyelet through both, welded seam, finished sides. Everything you could want in a long lasting rim.

I would recommend these as well - great rims especially for touring. I don't like most Mavic rims but that is one I will recommend for the right application.

Actually, he's one of a few people on this forum who knows what he's talking about.

From the the instruction manual that came with my Minoura Wheel Truing Stand TRUE-PRO:

"Understand that the nipple should not be loosened
at any time. Nipples are made from softer alloys or
brass and are prone to stripping easily."

It was inconsistent with the info I found on youtube so I ignored it.

Kam

Interesting, but definitely wrong. You can strip a nipple just as easily by tightening it (actually easier) as loosening it. I don't see why it would be a problem, and I have definitely needed to when truing older wheels... apparently the ones previously trued by people who own Minoura stands :D

I'm guessing translation error, possibly made worse by an intern with a slight, but incorrect, understanding of how wheels are trued.

That's kinda weird of Minoura to say, At least for the few wheels I have built and trued so far, I never had a problem with de-tensioning spokes and re-tensioning them again. Sometimes I have to do this when I'm not getting anywhere with the truing job and I want to start back to a good baseline so I de-tension all the spokes to start over again. Never had spoke or nipple threads (I use brass nipples) gall and seize on me yet. I think you should be OK to do this as long as you adequately lubricate the spokes and nipples
As for rim cracking/failiure at the spokes, Maybe there might be cases when a rim material wasn't tempered correctly at the factory, but failure like this is not as uncommon as one would think. I have read stories of lightweight rims like the Mavic GEL280 cracking at the spokes as the miles build up. It could be that sometimes rims crack when they are used not as intended by the manufacturer too.

Chombi

I can't believe no one has mentioned the number of spokes. Maybe I missed it within all the bickering going on. If you're going to get a new wheel built, 32 spokes should be a minimum, 36 is way better.
eyelets are nice, but not totally necessary. I've seen 30 year old wheels made with non-eyeletted rims that were in fine shape. I feel, and a number of well known wheel builders feel the same way, and the more spokes the better. (40 is great, but overkill with today's higher quality materials)
What I'm trying to say, is get whatever rim works for your budget and get the wheel built by hand, by an experienced wheel builder. A handbuilt wheel with 36 properly tensioned balanced spokes will always outlast even the "best" machine built wheels.
That being said, double walled rims are good, eyelets are good, double eyelets are better. wheelsmith, dt swiss, sapim spokes are the only ones you should be using. if you can get them custom cut, that's even better. there are a few bike shops in the bay area that have a spoke cutter (alameda bicycle comes to mind, and their wheel builder, dan, is the shizznit).

Open Pros.

/thread