Mavic CXP 30 tubular rivet question

[moose8]

So I recently took the plunge into tubulars and on my second ride I had a little problem - I'm not exactly sure what happened, but six driveside spokes broke - I assume I somehow had the rear derailleur adjusted wrong and must of just hit the spokes or something. The derailleur itself was fine though and was set properly, or so I thought, when in the stand. Regardless, six spokes ended up broken. Anyway, the bike shop just called and said that a rivet broke in the inside of the rim and can't be fixed or retrieved so they are beyond repair. A couple of questions:

1) has anyone had this happen, and if so are they truly goners? It sounds like it.

2) would the derailleur be the most likely culprit, or could the rivet have popped before the derailleur? It doesn't really matter either way in the end, but I am curious as to whether it was my bad mechanic skills (which seems highly likely) or if I just got unlucky with the wheel.

Thanks

[christian]

A rivet?

I had a pair of CXP30s and I am 99.999% sure they are welded at the seam, not riveted. Maybe they're referring to a eyelet that pulled out. If you pulled out an eyelet, then yes, they're toast.

And if you pulled out an eyelet, that was surely preciptated by a mechanical force on the spoke - the rear derailleur would be the likely culprit.

[christian]

BTW, those rims are apocalyptic in strength.

[moose8]

Originally Posted by christian

A rivet?

The guy who just called said rivet, but I bet you're right and he meant eyelet. He said there was something in the rim that rattled now. I can't believe the ways I am capable of screwing up my bikes. This one seems to have been pure stupidity on my part caused by rushing to put the bike together the night before my first cross race (where it worked fine). Then I took it out for my commute and it did not work fine. I was attempting to build an inexpensive beater but because of stupidity on my part, it's going to end up a more expensive beater. At least it's just a bike and nothing more serious I suppose.

[Mark McM]

Originally Posted by christian

A rivet?

I had a pair of CXP30s and I am 99.999% sure they are welded at the seam, not riveted. Maybe they're referring to a eyelet that pulled out. If you pulled out an eyelet, then yes, they're toast.

And if you pulled out an eyelet, that was surely preciptated by a mechanical force on the spoke - the rear derailleur would be the likely culprit.

Yeah, I'm guessing he meant a spoke socket, not a rivet.

The CXP rims didn't use eyelets per se; instead, they used sockets that were inserted in through the spoke hole in the tire bed. These sockets weren't crimped in like an eyelet, they simply sat loosely inside the rim, with tabs to keep them from falling back out through the spoke hole. In an unbuilt rim these sockets would rattle if you shook the rim.

The sockets were made from relatively cheap metal castings, and could be brittle. If a socket were to break, then it certainly could be loose inside the rim. That in itself is not catastrophic, but it would have to be replace before a new spoke could be laced, and I have no idea where you could get one of these sockets today.

In any case, it is hard to believe that you could have 6 spokes break without some noticeable event, such as a derailleur or a stick going into the spokes. Are you sure you don't know what event precipitated the breakages? A derailleur going into the spoke can certainly cause spoke breakages, but it generally results in damage to the derailleur itself, too. Where did the spokes break - at one of the ends or in the middle?

[moose8]

Originally Posted by Mark McM

In any case, it is hard to believe that you could have 6 spokes break without some noticeable event, such as a derailleur or a stick going into the spokes. Are you sure you don't know what event precipitated the breakages? A derailleur going into the spoke can certainly cause spoke breakages, but it generally results in damage to the derailleur itself, too. Where did the spokes break - at one of the ends or in the middle?

I think it had to be the derailleur, but what's weird is the derailleur seems fine. I had a previous issue with a bent derailleur hanger on a different bike, and the derailleur got destroyed when it touched the spokes, and it didn't break six spokes either but just a couple - here the derailleur really seems ok. I was pedaling hard because there was a bus coming up in my lane behind me, and all of a sudden the bike made a bad noise and everything froze up so I stopped pedaling and got on the sidewalk. I think the spokes all broke about a third of the spoke length from the hub, so that seems consistent with it being the derailleur - there's really no way I guess spokes could break in the middle without something being stuck in them I imagine. And they were all drive side spokes, so it must have been the derailleur.

[Look585]

No idea on the reason for spoke failure, but this is what's rattling around in your rims. They went in from the "tire side", so they can come out (with enough shaking) if you peel off the tire. Old Potatoe probably has them in stock.

[oldpotatoe]

Originally Posted by Look585

No idea on the reason for spoke failure, but this is what's rattling around in your rims. They went in from the "tire side", so they can come out (with enough shaking) if you peel off the tire. Old Potatoe probably has them in stock.

Yep, I do have some. Where did the spokes break? At the hub? Loose at the rim?

Breaking a number of spokes all at once, w/o knowing you chucked the RD into them, is 'interesting'..Gotta be something else.

I've seen spokes really mangled by a rear der w/o breaking 6 of them.

[Mark McM]

Breaking the spokes in the middle is consistent with something getting lodged in the spokes, but if the derailleur wasn't damaged, it wasn't likely that it was the derailleur. My guess is that you picked up something from the road which was carried up and got stopped by the stays, and that managed to snap the 6 spokes before it got unstuck. I've seen this happen before, although not with as many broken spokes.

[moose8]

Thanks for all the responses - the wheel is still at the shop. I'll have to pick it up to see if I can tell anything further. I did check the rear derailleur again though and it seems like nothing happened to it, and like I said before when I put a rear derailleur in a wheel before there was absolutely no mistaking it, unlike this time. We'll see. If it is indeed salvageable I'll call for that missing piece for sure.

[11.4]

Hmmm. I once picked up a 16-penny nail, jammed the sharp end right through the tubing of the chain stay, and it held so hard that the head of the nail just chopped up several spokes (non-drive side since that's the side where the nail stuck, not that it matters).

Once I encountered a goose on a big nasty downhill. It was either a crash, or a crash cushioned by a goose. I chose the latter. It was a mistake. The goose jammed into the fork and into the seat stay (yup, goose was definitely kaput) and just massacred the frame and also both wheels. Not even enough to walk home with. And I crashed hard anyway. Of course the goose no longer was in any shape to care.

All kinds of ways to break a wheel. That's the morale. But usually you know clearly what happened. That doesn't seem to be the situation here.

In this case there aren't really ferrules with rivets like on most rims. There are the little inserts illustrated above, and yes, they do fall out and you then can't install a spoke. But they don't fall out until you get the tire out of the way. If the issue is really with missing inserts, then your tire had to come off (assuming the rim isn't completely ripped apart). Please do send photos. So far, it isn't really clear what happened, and it should be.

[moose8]

I think the bike mechanic at the shop just diagnosed it correctly when I went in to pick up the remains of the wheel - he said it looked like my chain overshifted in the big cog in my cassette, jammed in the wheel and sheared off six of the leading spokes in a three-cross spoke pattern. That seems consistent with what happened as the chain was on the biggest cog when I pulled over - and everything was sort of frozen up.

I've attached a couple pics, but I doubt they will be very informative as all but one spoke with a loose socket attached were cut out - when he first told me the wheel was trashed he said he would cut the spokes out to make it easier for me to deal with so I said fine. He recommended against trying to rebuild it both because of the missing spoke sockets which are rattling around in the wheel and he thought the indentation by the weld didn't look good - I'm not sure if this is typical or not. Any of you guys know?

So I think I'll probably chalk this up as a learning experience and don't know if I'll build up another rear wheel or not - I may just turn the bike into a single speed with an existing wheel or get a different wheel.