Continental GP 5000 S TR popped off (Cadex AR 35 wheels)

[stjepan]

Hi,

Had a bit of a surprise yesterday when I came home from my ride. Front tire managed somehow to partially pop off the wheel (Cadex AR 35), never seen something like that. I did hit a few smaller pot holes on the ride, but nothing out of the ordinary. The tire is 28mm (practically brand new), which is compatible with those wheels (also new). Can't see any visual damage on both of them.
Anyone had a similar experience, don't know if this is something I should worry in the future? I mean, I had hookless wheels before (Zipp 303S and 404 Firecrest, also have Cadex 65 now) - none of those had similar problems (albeit didn't run them with Conties GP 5000 S TR).

[warthog101]

What pressure?

[stjepan]

What pressure?

65 psi, so within range.

[stjepan]

Forgot to mention, when I released the pressure the tire seated back in place instantly. Have inflated and deflated them couple of times afterwards - everything looks solid. Just don't know if I can trust them after this episode.

[TobinHatesYou]

I had a GP5K S TR partially pop off during a dumb crash with a hooked rim, but that was a crash...

This just reinforces my hesitation with going hookless despite being an early adopter for just about anything else. While hookless rims can definitely be made lighter, the main reason brands are pushing hookless is because they're cheaper to manufacture.

[stjepan]

I had a GP5K S TR partially pop off during a dumb crash with a hooked rim, but that was a crash...

This just reinforces my hesitation with going hookless despite being an early adopter for just about anything else. While hookless rims can definitely be made lighter, the main reason for brands are pushing hookless is because they're cheaper to manufacture.

Yes, this was not confidence inspiring. As I said, all other hookless wheels didn't present me with a single remotely bad experience so far. But one is enough to make me pause. Not sure how to proceed.

[warthog101]

What pressure?

65 psi, so within range.

Fair enough. Yes a bit of a worry.
I have hookless WR50s.
They are 25mm wide int, 32 ext.
I have a 28 on the front and a 32 on the rear. Not GP5k S TR.
60psi F and R is heaps at my weight of ~77kg.
The wide rim makes them quite large.
The rear stupidly so.

[Miller]

I notice the tyre bead has come off at the valve. Was it properly seated beside the valve beforehand? The space in the wheel well beside the valve can be tight, depending on rim inner width, and tyre beads can be reluctant to sit down properly. I'd recommend, with the tyre seated but deflated, to loosen the valve retaining nut and push the valve up into the tyre a little bit, then retighten the valve nut and inflate tyre. This will ensure a correctly seated tyre bead.

[kervelo]

Yes, this was not confidence inspiring. As I said, all other hookless wheels didn't present me with a single remotely bad experience so far. But one is enough to make me pause. Not sure how to proceed.

I think Continental might be interested in this case. Many years ago I had a strange tyre explosion (I think it was a GP 4000) and when I contacted them, they asked me to send the tyre to them for inspection.

[C36]

The only Cadex wheel compatible with the GP5k s TR is the Cadex 42. Seems to be clearly stated in their website.
Edit: limit seems to be only for 25mm, not 28

[kode54]

Tire stretch? Could be over stretched tire on a wide internal width rim. Not sure I would inflate them and ride on it again given the issue.

[stjepan]

I notice the tyre bead has come off at the valve. Was it properly seated beside the valve beforehand? The space in the wheel well beside the valve can be tight, depending on rim inner width, and tyre beads can be reluctant to sit down properly. I'd recommend, with the tyre seated but deflated, to loosen the valve retaining nut and push the valve up into the tyre a little bit, then retighten the valve nut and inflate tyre. This will ensure a correctly seated tyre bead.

I can't be 100% sure. I did however inflate and deflate them a couple of times + visual inspection before the first ride. All seemed fine. The incident happened on the 5th or 6th ride.
But I will go trough the recommened process, just to be on the safe side. I would very much like to continue using this combo, the tires roll beutifully.

[stjepan]

Tire stretch? Could be over stretched tire on a wide internal width rim. Not sure I would inflate them and ride on it again given the issue.

I don't think so, the tires are practically brand new, 5-6 rides on them so far.

[Mr.Gib]

I just hate seeing this. Guess I will abondon my plans to go hookless.

Yes, interesting that the blow-off happened at the valve, but so what? Even if the tire wasn't properly seated (which I doubt), it shouldn't even be possible for it to go over the top, certainly not at the stated pressure. Rather, the tire should settle in place after a couple of rotations on the road. Something is seriously messed up with that tire or less likely the rim.

Question, was the tire too easy to get onto the rim? The OP has lots of nice wheels and I assume knows what a tire that is too loose feels like, and how to properly install?

[stjepan]

I just hate seeing this. Guess I will abondon my plans to go hookless.

Yes, interesting that the blow-off happened at the valve, but so what? Even if the tire wasn't properly seated (which I doubt), it shouldn't even be possible for it to go over the top, certainly not at the stated pressure. Rather, the tire should settle in place after a couple of rotations on the road. Something is seriously messed up with that tire or less likely the rim.

Question, was the tire too easy to get onto the rim? The OP has lots of nice wheels and I assume knows what a tire that is too loose feels like, and how to properly install?

The rim seems fine to my untrained eye, it has no visible marks of defect or anything really. I will take the tire off over the weekend to inspect more closely however.
Tire-rim combination is at the allowed limit though - 25mm internal width with 28mm tire (supported by both Conti and Cadex in this instance).
To your question - it wasn't too easy to fit them, I had to resort to tire levers in the end to get them on completely (both tires).