Jimbo64

Anybody have sudden catastrophic air loss on Tubeless Tires? Tires ridden 8 months with no problems and sealant added every 6 months.

Rims: Giant SLR Tubeless Wheels
Tires: Continental 5000 Tubeless

Front tire deflated on Rt hand turn using 80 psi in tires. Speed 10-15 mph. Riding 33 mins and 9 miles at the time of incident.

Steve B.

Maybe you left in the summer air ?.

Swap out to winter air, ASAP

Jimbo64

Needing SERIOUS reply’s only.

just prior to ride, air was added to 80 PSI IN THE 25 mm road tires. Crash resulted in stitches and concussion.

shoota 

did you cut the tire on something?

DrIsotope

If the tire went out on you mid-turn, there's really no way of knowing what happened. I hit a shadow-obscured pothole at +30mph, which effectively destroyed the rim, but my tubeless tire didn't so much as burp. I've also had slow leaks bring a tire down below 10psi and ridden it just fine, at least until I could get somewhere to stop and air it up. Even if you burped a bead, it wouldn't lose all of the air all at once. If I were to wildly guess, I'd guess glass cut that was either pre-existing and "popped" in the corner, or glass cut inside the corner itself. It happens.

Some years back, I had a rear tire suddenly go to 0psi during a +20mph right hander, and essentially high-sided the bike. Cracked helmet, wheel destroyed. Absolutely no way to tell post-incident what precipitated it. Maybe the rim failed and took the tire out, maybe the tire failed and took the wheel with it. All I know is one second I was turning, and a second later I was flat on my back in the middle of the street.

Koyote

"Catastrophic air loss" generally means that the tire was punctured. That happens on occasion.

If you inspect the tire and provide more info (and perhaps photos), we might be able to provide more info.

Sorry about your accident. I hope you are healing up!

Jimbo64

Thanks for the thoughts.

to add more detail. I was doing laps around my neighborhood. I was on the 3rd Lap. The bike had not been ridden in 8 days. The last ride was 64 miles. Prior to riding, I inflated the tires to 80 psi. On the 3rd lap, I took a left turn and felt nothing out of the ordinary, went 50 yards downhill and braked down to 10-15 mph before turning right. Was out for an easy ride. There was no potholes or debris on the pavement. No sound was heard when the tire went down. Suffered concussion and cut requiring stitches.

the next day, I looked over the tire for sealant leak signifying a cut in the tire surface. nothing appeared on the tire signifying a cut. I did see sealant leak on the right side (inside of turn) of the wheel where the rim and tire met. I pumped tire back up. About an hour later the tire was flat. I re-inflated the tire and placed it in my tub to find the leak. This time no leak was found and the tire has remained inflated.

Andrew R Stewart 

So it seems we can rule out significant casing cuts or rim strip ones as these don't self fix. Any puncture/cut large enough to cause immediate loss of all air generally is too large for the sealant to seal. Valve failures also don't tend to self repair but also tend to be slow in air loss. Burping a tire bead on a road bike tire (only 25 labeled mms wide) can result in total or nearly so loss, there's not much volume of air in a skinny tire. Some sealant smearing on the bead after air loss is not unusual.

What I suspect might have happened was a slow puncture that allowed the tire to loose enough pressure so a burp (at moderate speed) around a corner happened. The puncture object was so tiny that it wiggled out once the tire was floppy. No evidence of a sealant "plug" was found as none had started. So the after incident inflation was with a still punctured tire. But now the sealant did do it's job (for whatever reason, like the sealant finally found the hole) so the second reinflation has held.

We have done many dozens of MtB tubeless tires and found that sometimes weird things happen then go away later. We attributed many to the sealant not doing it's job or not yet coating the point of leak enough to initially seal but did later. The, maybe couple dozen road tubeless tires we've mounted have seen a more disappointing service record. Small punctures that didn't seat till most all pressure was lost, more issues with rim tape leaks being the common issues.

Sorry to hear of your injuries. Andy

dim

are those rims hookless? .... if so, read this:

https://www.renehersecycles.com/safe...e-herse-tires/

tomtomtom123

Aren't tubes safer in respect to sudden air loss?

djb

just wanted to mention Andy, thanks for this (and all) your insights into stuff.
Ive never used tubeless, would only consider it if I were ever to ride the Divide stuff, and even then only the bottom half.
Anyway, its good to hear some experienced details of funny stuff going on and to at least bury these details into my brain to hopefully surface again one day if I have to deal with things...

to the OP, crappy instant accident. Years ago I had a front tire go down on a downhill, but thankfully it was slow and the steering felt funny and slowing, and was able to pull over in time. Losing the front instantly aint fun, we've all had it happen, and whether on a motorcycle, or a bicycle, on ice or pavement or whatever, its never good....

masi61

When you say you inflated the tires up to 80 psi prior to the ride, I’m wondering if that amount of pressure was insufficient to (re) mount your 5000TL’s fully. What I’m wondering is this: when you don’t ride your bike for a week or so and the tire gradually deflates lower and lower, the bead sort of pulls away from the rim shelf. When you use your foot pump to take it back up to 80 psi, the pressure is building back gradually and it might appear that all is well and that there are no leaks.

But I wonder if in actuality there is some retraction of the bead over the time of the gradual deflation that “sticks” the bead out of position in a way such that it holds air in the garage but fails on the road.

My thinking is that when re-inflating tubeless tires, it might be better to do a high pressure re-mount using a pressure canister (giving an initial blast of >120psi) to re-pop the bead fully out to the edge of the tire shelf on the interior of the rim. The tire could then be deflated down to the final pressure of 80 psi. Kind of the opposite direction of typical tubed tire inflation.

I’m just speculating here & hoping to prompt further conversation on this topic.

Sorry about your crash & subsequent injuries BTW. Hopefully the concussion left no lasting after effects.

Jimbo64

I appreciate all of your thoughts. Regarding the slow leak, I thought the sealant was supposed to stop slow leaks? I’ve been on rides before where a tubeless tire was punctured and slung a little sealant out hitting others, but he kept going. So shouldn’t the sealant have stopped the slow leak?

ThermionicScott 

I'm far from a tubeless expert, but that thought crossed my mind as well. We're sort of in the place where the automotive industry was when tubeless tires were introduced. The old-style rims didn't have humps for retaining the bead, so tubeless tires could unmount themselves if you let them get too low.

djb

To those familiar with tubeless, does low air pressures pose problems generally?
i weigh 135 140 and the narrowest tires I ride are 28s, so I'm not sure I would run 25s at 80.
How much do you weigh Mr crasher?

The questions about low pressures and beads and all that made me think of this aspect.

Steve B.

Not really. You can get a rapid loss of pressure in a tube, pinch flat comes to mind. You hope it doesn't happen while descending at speed or in a corner.

Amt0571

It cap happen, but it's less likely. Pinch flats happen only when you don't have the right pressure or are not looking ahead and hit something you shouldn't have hit in the first place.

I only had an "explosive" flat once, when a thick metal wire punched through my tire, my inner tube and almost managed to punch the rim. I've had several rapid deflations due to glass cuts that made me bin the tire as I could see the tube through the hole, but all of them gave me enough time to stop.

As I said, it can happen. But the tube is an extra barrier, and it's less likely.

tomtomtom123

Tubeless seems to me to be like going commando without underwear. You'll dirty your pants and get uncomfortable chaffing.

djb

The couple of times I've had rapid deflations have also been from weird rare "shiskabobing" from a long nail that got flicked up and stabbed rear tire, another time same thing but a long flat piece of metal flicked up again. Luckily not going fast.

jbucky1

Sounds like something cut or punctured the tyre for the air to evacuate rapidly. Can be pretty normal if you roll over some sharp metal or glass that tears a hole in the tire.

That would be my reasonable explanation without any other info.

- james

www.buckyrides.com

squirtdad

tubular are, but this is tubeless

squirtdad

this was my question also....80 on a 25 seems low.....but I am not a tubeless guy, so this is an education question as a big guy (245) i ride my 28's at max or close (115 psi for gp5000 28) and like 130 in a 25mm tubular

Reynolds 531 

I'm really liking this scenario:


When you say you inflated the tires up to 80 psi prior to the ride, I’m wondering if that amount of pressure was insufficient to (re) mount your 5000TL’s fully. What I’m wondering is this: when you don’t ride your bike for a week or so and the tire gradually deflates lower and lower, the bead sort of pulls away from the rim shelf. When you use your foot pump to take it back up to 80 psi, the pressure is building back gradually and it might appear that all is well and that there are no leaks.

rickpaulos

I got to watch one last year on RAGBRAI. Kaboom, followed by the rider squirreling all over and not crashing when he went off the road onto loose gravel. It was impressive to watch. Sheer luck he didn't crash. The tire was completely off the rim by the time he stopped. I offered to help as he seemed pretty clueless. Turns out he was putting 90-100 psi in and the sticker on the carbon rims said 65psi max. He didn't have a suitable inner tube so he had to walk back in to town for service.

Amt0571

IMHO it's not worth it for amateur riders even on a mountain bike. Replacing or patching a punctured tube is fast, easy and doesn't involve messy sealant liquids.

Lots of people disagree with me though. I can't say that I'm positive about the crap that manufacturers are pushing on us.