Little black balls in my Roval Traverse SL rims

[flyingdog]

Just wondering if anyone has seen this before?

I've got a set of Roval traverse SL carbon rims on my 2013 enduro. I run em tubeless with Stans sealant.

I was washing the bike after a ride tuther day and as the rear wheel was free spinning whilst in my stand I hear a rattling noise from the back wheel. I think maybe the sealant has dried up into balls so remove the tyre to find heaps of liquid sealant and no dried up balls. Then, when I shook the rim I hear the same noise and it's obvious that there is something going on inside the rim. So, out comes the valve and then I starts shaking little black balls out of the valve hole. These balls are easy to squash between fingers and they look like balls of carbon dust.

Anyone else come across this?

 

[ozzybmx]

It might be alu nipple corrosion which 'possibly' happens by galvanic corrosion... running carbon rims on dry trails with soft alu nipples and a reaction with stans.

I would pull the rim tape off and do a bit of investigation.

3 years ago I had similar balls in the void on my enve wheels http://forums.mtbr.com/wheels-tires/enve-wheel-nipple-corrosion-835853.html

 

[teK--]

Per above I reckon it's your alu nipples disintegrating. Get them rebuilt with brass nips.

 

[John U]

Were they chocolate and salty?

If so recommendation is to suck em.


Sorry, couldn't resist.

 

[pink poodle]

Were they chocolate and salty?

If so recommendation is to suck em.


Sorry, couldn't resist.

It is their best song.

 

[rone]

Seems to be a common problem, not just with Rovals, but with most high end wheels with aluminium nipples. The ammonia in the latex fluid corrodes the alloy and causes them to fail after a year or so. Can't imagine it's particularly good for the carbon, either.

Sells more wheels I suppose. Kind of an unspoken hidden cost.

Hence my preference for tubes.

 

[The Duckmeister]

Seems to be a common problem, not just with Rovals, but with most high end wheels with aluminium nipples. The ammonia in the latex fluid corrodes the alloy and causes them to fail after a year or so. Can't imagine it's particularly good for the carbon, either.

Aluminium nipples in carbon rims corrode anyway, regardless of the presence or absence of sealant, simply because the two materials do not agree with each other. Carbon fibre and the epoxy resins used to bind the stuff are pretty immune to chemical attacks - latex sealant is worse for aluminium rims than it it for carbon.

The bits floating around in the rim could be remnants from the manufacturing process.

 

[notime]

Here are my wife's Roval Carbon 29er nipples.

look fine on the outside but what a mess on the inside. I replaced them all with DT black brass.

I gave them a dose of Penetrene the day before I removed them and all but one (the very last one) came out ok.

 

[creaky]

This thread makes tears come out of my eyes as an owner of 3 sets of carbon roval wheels .... Never looked inside them.

 

[nzdans]

Cool! I removed some of these guys from one of my sets of Roval carbon wheels a few weeks ago.. Was kind of wondering. I'm buggered if I'll be fitting brass nipples, far too much of a weight weenie.. Will just stock up on alloy nipples and replace them every year or two.

 

[Boxer]

This thread makes tears come out of my eyes as an owner of 3 sets of carbon roval wheels .... Never looked inside them.

^ This! I have 2 sets and one set is 2yrs old, never broken a nipple but now nervous

 

[The Duckmeister]

Cool! I removed some of these guys from one of my sets of Roval carbon wheels a few weeks ago.. Was kind of wondering. I'm buggered if I'll be fitting brass nipples, far too much of a weight weenie.. Will just stock up on alloy nipples and replace them every year or two.

You know how much the weight difference is? About 50g in total. If you're that worried about weight go & squeeze out an extra shit before you ride.

 

[slimjim1]

So does this also happen to aluminium wheels with alloy nipples or is it unique to carbon? Seems odd that all wheels aren't built up with brass.

 

[hifiandmtb]

Here are my wife's Roval Carbon 29er nipples.

look fine on the outside but what a mess on the inside. I replaced them all with DT black brass.

I gave them a dose of Penetrene the day before I removed them and all but one (the very last one) came out ok.

Need more photos of your wife's nipples please. Can't quite make them out...

 

[ozzybmx]

Alu nipple = 0.31g and a brass nipple = 1g, so its 32g a wheel versus 10g, so only 22g per wheel penalty for piece of mind and reliability.

Take 5 identical tyres and they could vary by 50g, pick the lightest 2 and build your wheels with brass nipples.

 

[nzdans]

You know how much the weight difference is? About 50g in total. If you're that worried about weight go & squeeze out an extra shit before you ride.

I sure do know, nearly every part of all my bikes has been on the scales at some stage. I even dropped over 20kg of body weight last year (no shit)... Rotational weight is key & bling is best!! Gold nipples on order!

 

[notime]

Need more photos of your wife's nipples please. Can't quite make them out...

I tried to avoid the double entendre but I guess with wife and nipple in the same sentence it's inevitable..


A few other things I noticed, one rim was taped and one rim had the Roval tubeless strip and both wheels where equally corroded.

The rear rim was replaced well inside 2 years ago so check those rims out at 12 months

There is no corrosion where the alloy and carbon meet, those surfaces are clean. The corrosion is only where it's exposed to open space.

 

[hifiandmtb]

I've got Carbon Rovals myself, not a fan of the Revolution spokes either. Spoke windup & stretch is a problem.

I'll likely relace them with Comps & brass nipples when the time comes...

 

[John U]

I sure do know, nearly every part of all my bikes has been on the scales at some stage. I even dropped over 20kg of body weight last year (no shit)... Rotational weight is key & bling is best!! Gold nipples on order!

Sorry disappoint you, but gold is one of densest metals out there.

 

[The Duckmeister]

So does this also happen to aluminium wheels with alloy nipples or is it unique to carbon? Seems odd that all wheels aren't built up with brass.

Not to anywhere near the same extent; because the rim & nipples are basically the same stuff (aside from possible slight differences from the tiny quantities of other elements to make up the specific alloys) there's virtually no galvanic potential, so minimal corrosion. However, the nipples can still oxidise over time, which can cause them to become brittle & fail. Aluminium got a foothold because the mucketing boffins demand that a poofteenth less weight is more important than durability. Keeps me in a job though, 'cos I have to keep fixing the bloody things....