Kevalar Bead Failure???

Steelhead said:

Hi, all. I recently had a tire bead jump over the edge of my rim resulting in nasty blow-out. I re-seated the tire and tried it again with the same result. Bead stretches over the rim, tube blows out the side and bang: rapid deflation. Not good. I sometimes go all out, often with heavy city traffic buzzing by.

I've never seen this before. Has anyone else ever had this experience?

Tire: Vittoria Rubino Pro (new) 700X23
Rim: Velocity Aerohead (many miles on it, but very true)
Pressure: 115 lbs

I just bought these wheels used. They seem fine, good hook all around, true, and no blemishes or flat spots. Tires (even Contis) seem to go onto them a bit too easily. I'm wondering if rims possibly compress inward from spoke tension as they get older. Seems far-fetched, but possible???

Thanks in advance for sharing your experience/advice.

Never had the problem.Rims would more likely get hosed by running way too much pressure in them.

Buy another tire and try it out. Even a cheapie. If it comes off the rim, you may have been sold a defective product.

Steelhead said:

Hi, all. I recently had a tire bead jump over the edge of my rim resulting in nasty blow-out. I re-seated the tire and tried it again with the same result. Bead stretches over the rim, tube blows out the side and bang: rapid deflation. Not good. I sometimes go all out, often with heavy city traffic buzzing by.

I've never seen this before. Has anyone else ever had this experience?

Tire: Vittoria Rubino Pro (new) 700X23
Rim: Velocity Aerohead (many miles on it, but very true)
Pressure: 115 lbs

I just bought these wheels used. They seem fine, good hook all around, true, and no blemishes or flat spots. Tires (even Contis) seem to go onto them a bit too easily. I'm wondering if rims possibly compress inward from spoke tension as they get older. Seems far-fetched, but possible???

Thanks in advance for sharing your experience/advice.

Steelhead said:

Hi, all. I recently had a tire bead jump over the edge of my rim resulting in nasty blow-out. I re-seated the tire and tried it again with the same result. Bead stretches over the rim, tube blows out the side and bang: rapid deflation. Not good. I sometimes go all out, often with heavy city traffic buzzing by.

I've never seen this before. Has anyone else ever had this experience?

Tire: Vittoria Rubino Pro (new) 700X23
Rim: Velocity Aerohead (many miles on it, but very true)
Pressure: 115 lbs

I just bought these wheels used. They seem fine, good hook all around, true, and no blemishes or flat spots. Tires (even Contis) seem to go onto them a bit too easily. I'm wondering if rims possibly compress inward from spoke tension as they get older. Seems far-fetched, but possible???

Thanks in advance for sharing your experience/advice.

I've been riding Vittoria Diamonte Pro's for the last few months. They seem to seat over the rim easier than they should, and I've been concerned about them blowing off the rim, although it's never happened. I don't know if Vittoria is using a softer rubber compound. There rated to 150psi, in your case, you were well under the limits (although it sounds like pressure isn't really the issue anyways). I would do as the others suggested and try a different tire.

OCRoadie said:

I've been riding Vittoria Diamonte Pro's for the last few months. They seem to seat over the rim easier than they should, and I've been concerned about them blowing off the rim, although it's never happened. I don't know if Vittoria is using a softer rubber compound. There rated to 150psi, in your case, you were well under the limits (although it sounds like pressure isn't really the issue anyways). I would do as the others suggested and try a different tire.

Thanks. My sense is that it's probably a defective tire. I've had other loose fitting tires that I have ridden down to the threads at high pressure without the bead stretching over the rim like this. . . I'm just wondering how often this happens to other riders.

Is the tire the right size for the wheel? There is a difference between 1.25 and a 1 1/4" tire. Also, if the tire is too wide for the rim this can happen. For a given rim width there is a limited range of tire widths that will work reliably.

See:Sheldon Brown

TD

tyler_derden said:

Is the tire the right size for the wheel? There is a difference between 1.25 and a 1 1/4" tire. Also, if the tire is too wide for the rim this can happen. For a given rim width there is a limited range of tire widths that will work reliably.

See:Sheldon Brown

TD

Methinks he said 700x23, and Velocity aeroheads. Hard to go wrong there. I gots a couple of the same setups.No issues with several different kevler bead tires in 23.

boudreaux said:

Methinks he said 700x23, and Velocity aeroheads. Hard to go wrong there. I gots a couple of the same setups.No issues with several different kevler bead tires in 23.

Well, I just got back from a pretty brisk 35 mile spin after putting a new Conti Grand Prix on the rim, and it seems fine. . . On closer inspection the bead on the Rubino Pro is very lumpy and uneven. I think the tire is just plain defective.

I would advise people to avoid these tires, or at least inspect the beads and make sure they're even, then pump them up to max pressure and let them sit a few days before riding on them.

Man, it's still cold here in NYC. . . just getting some feeling back in my toes.

p.s. I like these Aerohead rims. They're very nice.

Steelhead said:

Well, I just got back from a pretty brisk 35 mile spin after putting a new Conti Grand Prix on the rim, and it seems fine. . . On closer inspection the bead on the Rubino Pro is very lumpy and uneven. I think the tire is just plain defective.

I would advise people to avoid these tires, or at least inspect the beads and make sure they're even, then pump them up to max pressure and let them sit a few days before riding on them.

Man, it's still cold here in NYC. . . just getting some feeling back in my toes.

p.s. I like these Aerohead rims. They're very nice.

Construction is VERY important in bead seating. If the plies "slip", equalizing tension in the outer and inner plies, the bead no longer will have enough projection to hook into the rim, resulting in a blowoff.

You can cut the beads completely though with no ill effects as long as the bead properly hooks into the rim. Proper tires will show no bead on the inside surface of the tire.

Sounds like a duff tyre to me.

Take it back , it should be replaced FOC by the retailer. If not, Vittoria are very good and will refund you no probs.

Cheers

bicyclerubber.com