Redbullet

Never happened to me, but I am wondering…
Scenario: Ride tires (and tubes) in good shape, in mid recommended pressure interval and no tough obstacles visible on the road. But still: tire (or tube) blows up on fast descents, while riding straight line or cornering. Does it happen? What can generate it? Can it be avoided?

Elvo

Yes if you have rim brakes and ride the brakes to the point that the brake track overheats, you could burst your tyre/tube

jaxgtr

This.....

popeye

The most common cause is getting the tube under the bead of the tire at some point. With tubeless there is the "burp factor".

WhyFi

Road tubeless? No, not really.

tempocyclist

Yes, by not dragging your rim brakes all the way down 20km long descents.

popeye

Really.
There's an interesting discussion in the latest Velonews 'Technical FAQ' column regarding burping in road tubeless tires. It is discussed that burping of high pressure, low volume (road) tires is more likely to result in a completely flat tire than on low pressure, high volume (MTB) tires, and how this can be safety issue in some circumstances. Jan Heine wrote a blog post titled "The trouble with 'Road Tubeless'" about this same issue. In a recent edition of his Marginal Gains podcast, Josh Poertner of Silca interviewed representatives from Maxxis tires and Stan's No Tubes, and they discussed that there are not yet any universal standards for road tubeless tires and rims, and aren't likely to be for some years.
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This weekend I had a nice ride planned with some climbing. Climbing of course mean descending. I was descending a steep climb (roughly 20-22%) at about 30 MPH when my front tubeless tire instantaneously blew off the rim.

The descent was new pavement with no debris.

It all happened so fast. A loud bang, the noise of my rim on the asphalt, then sliding and tumbling down the road with my bike.

The tire was a Specialized Turbo 2bliss mounted on a Giant SLR-1 wheel. The tire is 2 months old. The wheel is 2 years old.

The bead did not rip out of the tire. In fact I remounted the tire. I’m not going to ride it, I mounted it to see what the level of damage was.

I’ll be changing to clinchers, but I’m also looking to see if anyone else had experienced a tubeless blowout and if anyone has ideas on a cause.

WhyFi

Yup, really. Instead of searching for scary stuff, and dredging up the "latest," "most recent" three year old blog posts, you should actually read and get hands-on - you might learn something.

rsbob 

Had a front sidewall sliced clear through by a piece of metal and the tube immediately protruded though it, created a good size bubble and then exploded like a rifle shot.

The good news is that this happened after a 40 MPH descent just when I hit the flats. The sound it made scared the you know what out of me.

10 Wheels

Front Tire 17 MPH Blow Out.

canklecat

I've never had a tube or tire failure that wasn't attributable to operator error, puncture, road hazards, or equipment mismatch.

My errand bike came with rims that seem slightly undersized, making most tires fit loosely. If I'm not careful to ensure the bead seats properly during inflation the tube will sneak out and rupture. So far that's always occurred indoors shortly after installing the tire. Switching the rear wheel resolved that issue. Now I need to replace the front. Or switch to tighter fitting tires, such as the notoriously tight Continental Ultra Sport II.

One of my latex tubes seemed to have a thin spot, the equivalent to an aneurysm, when partially test inflating it to check for punctures. It would probably hold within the confines of a tire. But I retired that tube after two punctures anyway, since the second hole was at the base of the valve stem and difficult to patch properly. I'll cut it up to use as patches for other latex tubes.

We don't have any mountains here, and no downhills steep enough to require more than occasionally touching the brakes if it's a group ride and others are slowing. No risk of overheating.

DangerousDanR

I have had two Continental GP5000tl tires fail when the bead separated from the tire casing. The short version is now viewable here:

https://www.saferproducts.gov/Public...portId=3455430

If there had been a tube in this tire I have no doubt it would have failed in exactly the same manner. Both tires that failed were near the end of their usable tread life and both were replaced with another GP5000tl. My plan is to replace the tire when the wear dots get close to the ones on the failed tire, which I still have.

But since I have seen others post similar failures here on BF, I passed it along to the CPSC. They in turn passed the information along to Continental Tire. I have also sent e-mails and even called Continental. No answer from them and it has been about a month. I expect that I will hear from them "Pasado maρana"

Carbonfiberboy 

No, you don't "burst" anything. You blow the tire off the rim. The tube comes out through the rim/tire gap and goes BOOM. We did that on our tandem a couple times before we got it sorted: different rims and tires. I've never personally heard of a blown tire.

big john

Really? You've seen this?

WhyFi

I'm sure that this is one of the reasons for the move to the GP5kS TR; bead issues were one of the reasons that the GP5k TL were one of the only high-performance TL tires that weren't approved for hookless use. With the new TR, Conti has finally joined the party with ETRTO compliant tires.

popeye

So the best you can do is to resort to a personal attack when you are unable to debate facts. PLONK

WhyFi

Your "facts" are laughable and a waste of time to debate; if you think that what you've provided is actual evidence of any significant risk of road tubeless burping, nothing is going to convince you otherwise.

Oh, and calling out ignorance isn't a personal attack. It is what it is - you don't know what you're talking about.

ThermionicScott 

ETRTO has already published standards for road tubeless, the manufacturers just need to get with it: https://cyclingtips.com/2021/09/nerd...res-confusion/

WhyFi

Yup, and it was already in play behind the scenes, with high-end compliant tires hitting the market two years ago - so much for the veracity of his "latest" and "most recent" blog posts that said it wasn't on the horizon.

Trsnrtr

Same. We use to have Shimano Sweet 16 rims on our tandem and had similar problem on long descents in the Rockies.

Carbonfiberboy 

Rim brakes or discs?

popeye

SLR is rim brake only.

Carbonfiberboy 

OK, simple. You overheated your rim and blew the tire off. Not the tire's fault. Same thing probably would have happened to a clincher. You should descend steep grades by letting the bike run, staying off the brakes, then braking hard and briefly for corners, obstacles, driveways, etc. Sit up and use your air brakes. On most descents, terminal velocity is only ~55 mph if sitting up. No fear, just pay attention. I've found that deep alu rims provide the greatest margins descending, as they have more mass to absorb heat and more surface area to dissipate it. Light climbing rims are the worst, too bad.

Atlas Shrugged

That pretty well covers it!

Redbullet

So, it looks it can occur primarily due to equipment mismatch or overheating from rim brakes. It sounds somehow encouraging, since both reasons can be avoided.
But what about tubes? Can they suddenly suffer critical failure due to aging? Is there a replacement period for them? I mean really a reasonable "good practice", not just obsessively replacing them 2-3 times a year for some extra security...