[Closed] Cracked rim?

You need to put your image on a hosting site, you've just posted a Google Photos link that nobody else can access.

Edit. Here's the picture.

Hopefully the new links work?

Wow, that doesn't look good, get them warrantied ASAP.

Not sure I'd be comfortable riding that.

Trail wides? I found the sidewall too flimsy.

Never seen a rim crack like that before!

Who makes Hunt rims?

Cannondale.

Odd crack, possibly a flaw in the lay up.

Layup? That's an alloy rim isn't it not carbon.

Never seen a rim crack like that before!

That looks more like a manufacturer fail than damage from riding.

I'm sure hunt will want that back and warranty it.

My bad, too early, without looking at the thing properly and seeing word hunt, I autothought of carbon! 🙈🤣

😂 either way it's stuffed.

I've not had much luck with wheels on the Cotic. The Hunt set were replacements for a duff set of Superstar-hubbed wheels that came on the bike originally!
I'll hopefully hear from Hunt on Monday (or I'll call them) as this is my only bike and is now unrideable. I'll keep you posted.

The single biggest introduction of load to cause a failure like this would be bead seating.

"The single biggest introduction of load to cause a failure like this would be bead seating."
Sorry, I'm not sure what you mean by this? FWIW, the tyre was fitted by Cotic in August last year, I've done approx 1100km on the bike without touching the tyres, so when you say "bead seating" is that refering to a design issue at Hunt or an incompatability issue between tyre and rim?

Just a comment on how the load has cracked the root of the rim bead. The lifetime loading that will have introduced the greatest single instance of load in this location. When we hear a bead snap into place with a satisfying crack that is a hammer blow. Dry assembly of tubeless tyres with excessive pressures result in the biggest loads and the biggest shock loads. I have no way of telling what this rim has suffered, but this is a conceivable manner by which a single peak loading would have been experienced.

From a purely engineering POV, this will be a fatigue failure. Aluminium alloys fatigue. The further the loading stays away from the material limits, the longer aluminium structures last, but even with moderate loadings aluminium alloys eventually fatigue. When a structure reaches fatigue failure earlier than we expect we look for the cause of initiation. In examining this rim I would look for stress risers in the design or treatment of the rim. Is the failure anywhere near the join? Could it be heat treatment related after welding?

In the absence of evidence of a mechanical initiation, you then have to consider the nearest the structure has come to overload. Hence, I mention the bead seating on a 2.6 inch tyre. Hunt's specification for this rim says maximum 30psi for a 2.6" tyre. If you didn't overpressurise the tyre, the fitting of the tyre is the most likely time 30psi was exceeded and the bead seating would be a likely event for overloading.

But this is conjecture and circumstantial evidence at best.

We always chase optimum performance from lightweight components. Manufacturers chase thinning of wall profiles to meet market expectations. "Strong, light, cheap? Pick two", etc. Material for material, thinner profiles are weaker.

Fatigue in aluminium happens. It has a statistical likelihood of occurring. Without evidence, you are just unlucky. If the component is marginal for your use, either change your use or replace with a stronger alternative. Light rims with big tyres? Such a combo is always going to be challenging at exactly the point where your rim has failed.

Ah, gotcha!

Tyre pressure varies between about 20-24psi, so within "regular" tolerances. Not sure about tyre installation though...

Would an issue caused in August last year (say when the tyres were being installed) show up now though?

I'm interested to hear what Hunt say.

Interesting post peaslaker.👍

Good luck with getting it sorted asap op, annoying eh?

So Hunt got back to me and have sent out a replacement rim for me to get built up at my LBS. They'll refund the cost of wheelbuilding. The process has been pretty smooth and pain-free thus far.
I could have got Hunt to rebuild the wheel but it would have been probably close to a two week turnaround, so easier to get it done locally.
Pleased with things so far.

That's well done from Hunt, most places wouldn't offer the local wheelbuilding

I've probably installed thousands of tubeless tires and this has never been an issue. I'd say the sound / impact that is caused from the tire seating is more akin to being spanked rather than hit with a hammer 😉

Yeah, fair play to Hunt good response.

Pretty alarming looking failure though, and sounds like they haven't asked for the rim to be sent back, suggests they've seen it before.

suggests they’ve seen it before

They have. I know of two riders with exactly this issue, and google images shows the same but on a road wheelset under 'cracked hunt rim'.

Snap!

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30 -35 psi with rimpact insert fitted - boo
19 month old rim, hunt happy to sort under warranty no quibble - yay
Found another crack packing the wheel up for collection - boo
Can't be sorted until mid-late oct earliest as no TW 27.5 rims in stock - boo
Hunt offered loan wheel in the interim (seconds from their return scheme) - yay
But had already picked up a second hand wheel to keep me rolling in the interim - boo

Feeling a bit conflicted here - fab service, perhaps could have been quicker to let me know about delay, and should this have failed so spectacularly? Seems to be a common fault too. I've been a big advocate of Hunt to date, prob would recommend again, but with a 'careful on the rocks' caveat.

I think I can see the reason yours failed, though - the OP's seems to be missing that

Oh I'm not denying there's some culpability here! Just cool they've cracked in the same place. And shout out to Hunt service. I think.

Your looks to have been caused by whatever made the impact dent on the rim but, the cracks all seem to run along the joint area where the bed of the rim meets the side wall.

Maybe this is a defect in manufacture or design, which hasn't been picked up on stress tests or simulations that the factory do when designing rims in the first instance.

Good work by Hunt for sorting them out quickly although it does make me wonder just how much work goes into R&D for what is probably a pile em high, sell em cheap generic rim.

The replacement rim came, I dropped it down to my LBS at lunchtime yesterday and picked up the rebuilt wheel at about half one today.
So (1) very pleased with the Hunt warranty service, (2) very pleased with the wheel building service at Slam69 but (3) now a bit nervous about rim integrity with this wheelset. A careful eye will be kept on them, particularly after any rockier rides.

I had a rear 29er Trailwide fail in exactly the same way as the OP this time last year.
No dent, just noticed the crack after a (non gnarly) 36 miler on my SolarisMax.
Was running a 2.4 Ardent at 24psi. I'm under 80Kg kitted out for reference.

Wheels were 4-5 months old.
As with the OP, Hunt warrantied without issue and re paid me via PayPal for the local rebuild.
No issues, or dents, since then.

P.S. Hunt didn't ask for the old rim back.

I had the same thing happen on my trail wides. I eventually had a warranty replacement after a three month wait. The new run dented on its first ride.

Bit unfortunate for them that the cracks appear by the logo!

Am I being overdramatic here, but if that was happening on cars on a seemingly regular basis the manufacturer would be doing a recall? I've had a number of Hunt wheels and their service has been exceptional but those images are slightly worrying.

Presumably all on alloy rims not carbon?

Is this an example of a place where carbon is actually better than alloy? (As opposed to just sexier)

If it is, it’s a modest boast being better than a cheap Alu rim with design and manufacturing issues.