Aluminum wheels - rapid failure at the spoke holes

Curious if anyone has experienced anything similar.  At the start of my last ride I was surprised by a significant wobble in my rear wheel.  It turns out that about 20% of the spoke holes resemble the one in the photo.  These are OEM wheels from WTB that came on my 2020 GT Grade Carbon Expert.  I'm 100kg and have ridden a bit more than 5000km over two years (or to be more exact, about 26 months or +2 months from WTB's 2-year warranty period).  They've been tubeless from the start, using Doc Blue sealant and a variety of tires.  I ride year 'round.  I've of course grounded the bike and have new wheels on the way, but I find this a bit bizarre and would like to understand what has happened.  The front wheel looks fine (although it will also go in the bin to be safe...).  Anyone have thoughts, or similar experiences?  

I've had that happen before, on well used wheels.  Could be a combination of factors.  Fatigue from use and over tightened spokes?

This how all aluminum wheels end up, but it usually takes decades. You don’t have a lot of miles on them.  I guess they are just low end/weak rims.  

I've never had that happen in 50 years of regular riding on aluminum rims.  Never even had a wheel get noticeably out of true.  But most of my wheels were hand built with 32 or 36 spokes and rims tending towards durable as opposed to light.  I did wear out a couple of rims at the brake tracks.

The same thing happened to some WTB frequency rims I had 10 or so years ago.  There might have been a recall on them because apparently they used too soft of aluminum.  

ljsmith wrote:This how all aluminum wheels end up, but it usually takes decades. You don’t have a lot of miles on them.  I guess they are just low end/weak rims.  

Or over tensioned spoke.  ...and "decades"?   You must be old too. 😝

Thanks all.  The wheel did have to be trued by my LBS very soon after new, as several spokes had completely de-tensioned within a few rides.  Whether the spokes were over-tensioned at that point I can't say, but the shop seems good.  And it's similar in a half dozen places around the wheel.

I can't find much suggestion that sealant can lead to corrosion.  On the last tire swap I replaced the OEM rim tape and noticed consistent corrosion around the inner surface of the spoke holes.  Perhaps there is a galvanic corrosion aspect given the combination of steel and aluminium, but this construction is nothing unique. 

I think more likely is poor quality aluminum, as suggested in your replies, in an effort to keep the price down on a mid-grade OEM build.  My mid-grade MTB has WTB wheels with similar markings and total use, and I've just found a small crack at one of the spoke holes.  A sign of things to come, obviously.

I've shared photos with WTB to see what they say, and will share the reply if they write back -

By the by, this is a photo of a tear in the rim, made by me when squeezing spoke pairs by the side of the road.  I didn't share this photo as it isn't what occurred in the course of riding, but it demonstrates how weak the aluminum has become...

 

Update:  WTB has replied, suggesting over tensioned spokes.  I'm not sure of that explanation, as my MTB with such similar wheels is developing the same problem.  I'm not interested in a replacement of the same - better to be out of pocket where safety is concerned, so more comfortable with something else.  But impressed by their quick response and offer to replace it (out of warranty) nonetheless.
 

For interest, there are the two suspect spoke holes on my MTB's rear wheel - also WTB and with similar sounding markings.  Two years older, but used for half as many miles (although with more abuse, of course).  Less advanced, but it's obvious where this is headed as well...

mike wrote:
Or over tensioned spoke.  ...and "decades"?   You must be old too. 😝

I started riding in 85, does that make me old?

It sounds like this is GT's fault and I suggest contacting them as well. Perhaps it's a common problem and they'll do something about it. WTB's willingness to help is commendable, as they're not responsible.

With aluminum rims, once you over-tension them, they're toast and it's just a matter of time until they fail. I'm not ragging on Al wheel, as it's pretty much all I ride; it's just the nature of the material. It's possible that the reason your spokes loosened initially was because the rims had already started to yield. Re-tensioning may true the wheel, but the damage is done and it will just get worse.

This seems to be more of a problem on anodized rims - hard anodized in particular - as the anodized surface is harder and more brittle than the underlying material, so it's more prone to cracking. Once a crack starts at the surface, it will propagate through the rest of the rim. This can occur when the wheel is initially tensioned, at which point it's doomed to failure. I suspect that's your situation.

I started riding in '62, so no, you're not old! 😋

bnystrom wrote:
With aluminum rims, once you over-tension them, they're toast and it's just a matter of time until they fail. I'm not ragging on Al wheel, as it's pretty much all I ride; it's just the nature of the material. It's possible that the reason your spokes loosened initially was because the rims had already started to yield. Re-tensioning may true the wheel, but the damage is done and it will just get worse.

Thanks very much.  Very helpful and sounds like it could be the history of this wheel.  It was built really badly initially, so maybe doomed at that point.  With luck the replacements (Mavic Allroad S) will come ready to go, and last a long time before they need any spoke maintenance.  When they do I'll research a bit and discuss carefully with the tech first (I can hack through a lot of the maintenance tasks, but would not likely to well at wheel truing...).  In this case it never occurred to me as I thought Aluminum wheels could more or less be maintained with a hammer :-) 

Aluminum wheels are generally very rugged and relatively inexpensive - at least compared to carbon. In a pinch, it's amazing what you can do to an Al rim to get you home. I refuse to pay the exorbitant prices for carbon wheels, as I can build my own Al wheels for a fraction of the cost (typically under $300/pair) and maintain them myself. Speaking of which, one thing to avoid is wheels with proprietary components, such as special spokes or rims/hubs oddball spoke counts that aren't readily available at shops or online. This is often the case with Mavic wheels, but it doesn't appear to be an issue with the Allroad S (worst case, pick up some spare spokes). I've had a few pairs of Mavic wheels over the years and they're generally very well built, and their warranty service is good. I had a hub flange fail on a wheel years ago and they replaced it, no problem.

Glad to hear that.  I chose these rims because the spokes don't pass through the inner rim surface and, whether right or not, I thought this might make corrosion less likely this time around...  

I have a pair of Mavic EN821 rims which use hollow aluminum screws inserted from the underside to hold the nipples.  Nothing but aluminum and rubber contacts the aluminum rim.  A side benefit is no holes on the top side so no tape needed.

If your other rims were properly taped, there would have been no access to the inside of the rim for the sealant, plus the sealants currently on the market don't cause corrosion, so it probably doesn't matter. That said, not having to tape rims is a nice bonus! 👍

Mark_S wrote:For interest, there are the two suspect spoke holes on my MTB's rear wheel - also WTB and with similar sounding markings.  Two years older, but used for half as many miles (although with more abuse, of course).  Less advanced, but it's obvious where this is headed as well...

Headed? It’s dead.
I have had this happen with several WTB and Velocity rims, and at tensions below 125. Once it cracks it is weakened and will crack/tear more easily as your previous pic shows 

Note to self:  Never buy WTB wheels or rims.  😟

ljsmith wrote:

I started riding in 85, does that make me old?

Well, not really.  My first nice french race bike with tubular tires was in 1971, Then I decided to start racing in 1984 and raced for 12 years.  I'm old. 😂

Same thing happened on some the WTB rims (different model) that came as OEM on a bike of mine. I had about 4,000 miles on 'em, and the rear wheel had developed quite a few cracks. I caught them before they became as bad as yours and replaced the wheels.

If you poke around on bike forums, you will see LOTS of reports, just like yours, involving WTB rims. I don't know if they're junk, or if it's just because they provide lots of rims for OEM wheel builds, which may not be done with the greatest care. All I know is that, since it happened to my rims, I have stayed away from WTB.