tomtomtom123

The way I see it, all this talk of "burping" from a hard bump or something pressing against the sidewall seems to be quite an inconvenience for saving a bit of weight by not using a tube. With a tube, you won't (usually) get any accidental release of air from bumping into something. I've never gotten a "snakebite", but maybe others have (although I have always had tires wider than 1.6" (40mm) in thickness). Perhaps it's something more common for people doing jumps and drops (or riding on extremely narrow tires) compared to simply riding on smoothly paved roads.

Pinching of tubes between tire and rim is avoidable with careful tire installation. Punctures, at least for me, are usually not a sudden loss of air, but happens over at least several seconds with enough time to slow down and stop. I've been told that the sealant in tubeless setups will seal punctures of the tire, but if you really wanted to, you could also fill tubes with slime, although some people tell me that tubeless sealant is more effective than tube slime. You're still getting less chances of catastrophic air loss with a tube when riding on paved roads.

Someone on another thread mentioned "ghetto tubeless" for rims that aren't designed for tubeless. It involves wrapping the rim walls with a tube sliced down the center, installing the tire, filling it with sealant, pumping it with air, and then trimming the excess tube that sticks out from in between the rim and tire. Then, every time you want to remove and reinstall your tire, you have to sacrifice a new tube. Seems kind of pointless when you can just use the tube normally instead of cutting it up.

djb

tubeless clearly has advantages when riding in areas with thorns that are all over the place and result in getting ten flats a day or more.
this fellow made it clear that there was no apparent and clear cut or tear or whatever on tire, so it wasnt that.

jimbo--you didnt get back on your weight re wondering about the 80psi thing? Maybe you are sick of the discussion, but I would be curious to know if this was a factor.
I have no plans to run tubeless in the near future, but like to learn new things and get good info to stick in my craw for future reference to hopefully avoid something like what happened to you.

oh, I have witnessed someone go down in a turn with a regular tubed wheel, where it was pretty obvious that the guy had had a slow leak but hadnt noticed it, but going around the 90 degree corner had either the tire simply slide/fold due to lowered pressure. After checking up on the guy with other people, one of us moved his bike and noticed his front had gone down. Didnt appear to be a regular rider and probably didnt feel or notice the front going down before he turned---maybe not connected to this event, but I can see the similarity at least to some extent despite being a tube story.

Sy Reene

No comment on the rest of your post, but a tubeless tire generally weighs the same compared to a standard tire + tube (using a Conti GP5 comparison of 25mm -- 295 vs 221 grams for TL vs Std).

djb

and thorn goat head issue aside, I generally ride about 5000kms per year and maybe get one flat a year average over many many years. And can have seasons with no flats. So for my riding area and where I have toured, Im a touring guy, so far its not been an issue using tubes from a pragmatic side of things. Have toured through Central America and about half of Mexico (and lots of touring over the decades) and no flat problems at all really, so I'll be sticking to what I know and am used to....for now anyway....maybe one day.

TiHabanero

Like Andy, the first thought that came to mind was he rolled the tire. Seen this happen with tubular tires and I suspect if the rim is hookless, it is very possible to do with a tubeless tire, except with a tubeless tire it may roll just enough to allow a massive rush of air out and then settle onto the rim again. Speculation for sure, but certainly this needs to be looked at.

2old

Seems like there are occasions in which tubeless bike systems "bloot", at least in the MTB world (I don't know anything about road bikes). Happened unexpectedly to a friend, but no injury and he aired it back up and has had no more problems. My son was part of a group that rescued an individual who had that occur on a gnarly section off road. The guys face wasn't a petty sight. The best "protection" that I "know" (but maybe not really) of is a tight fitting tire on the rim.

djb

to you guys with lots of experience, what do you think of the 80psi thing, could that be a factor?
As a 135lb er , I sometime run my 28s with tubes to maybe 80 rear or a bit less, and then less psi on front tire, for riding on really rough stuff, but thats about my limit--but I ride light also and am careful, and prefer a bit more pressure for hard cornering.
I may be wrong but I assume that this person is heavier than me, so would 80 be a factor in this theory, or would it necessarily need a lowering from that from a slight leak like Andrew thought?

jadocs

I think there is a tolerance issue with the wheel and tire. I googled your rims and found more than one example of total blowouts.

https://www.google.com/amp/s/amp.***...uring_descent/

https://www.velonews.com/2019/10/bik...nd-more_501233

aggiegrads

I'm still skeptical of road tubeless in general. I won't run tubeless unless I can run less than 60 PSI or greater than 35mm rubber.

The only way that I would run road tubeless up to 90PSI is with a "matched set" of tires and rims from the same manufacturer. This is one area where the bike industry really needs to get its act together.

DrIsotope

While I wholly understand people exercising caution, the avoidance of high-pressure tubeless isn't really founded in anything real-- it's a phobia, I suppose. I have a good bit past 10k miles on tubeless 700x23 and 700x25 tires, and have never really had an issue that I would consider unique to tubeless. I've used four different wheelsets and at least half a dozen different brands of tire, and never had a problem with any of them.

Jimbo64

Sorry that I’ve not responded to questions about my accident. I appreciate everyone’s thoughts and feedback.

In initially checking with Giant regarding the setup on their tubeless ready wheels, they recommended 70-80 psi for the 25 mm tires @ my weight, which is 185 lbs.

The time & day of the accident, it was a sunny afternoon about 45 mins before sunset & the temperature was 47 degrees.

BTW, the tire is still holding air as of 11 days post accident.

Going forward, I’m taking the tubeless tires off, putting on Continental 4000s and tubes.

As a side note, I had a new Bontrager Web Cell helmet. It advertises as a 48x (times not %) less likelihood of concussions vs typical foam helmet. I notified them of the accident t and as part of their Accident Replacement Guarantee has one delivered to my house yesterday. I am sending the damaged helmet along with a description of the accident and injury. My “morning after” facial photo would be the mother of all mugshots!

jimbo

Road Fan

Once on the MUP I came on a fully-kitted road rider at the side of the path staring at her flat tire. Wife and I stopped, and my wife asked her to let me take a look. The tire was about 23 mm (narrow racing clincher rims) and tubeless and the tire was totally separated from the rim. She had just taken delivery of the bike and was out on her first ride. There was no clear sign a puncture or outer surface damage or otherwise of how it started. The sealant was gooey all over the outside of the tire. I tried to realign the tire edges inside the beads and get some air it it, but it didn't work and we were out of options - she had to walk back to her car. I assume that for some reason, perhaps a bump, the bead separated and there was sudden deflation. Tire traction then pulled the beads loose completely.

Just an idea. Can a tubeless bead be knocked out of engagement by riding over a bump with insufficient tire pressure? Is there some kind of bead adhesive that could have helped keep the air in?

DrIsotope

Yes, it's called "burping." The rider on the MUP had it worst case, because the air volume in a 23c tire is pretty small-- so when it burped, it just went dead flat. The tire was either not fully seated to begin with, or run at far too low of a pressure.

A blast from a CO2 inflator might have gotten it to re-seat. Shame on whatever shop sent her out on the road as a tubeless neophyte on 23c tires.

jbucky1

Nowadays tubeless is great. Yes its more fussy and specific than tubes, but if you have tubeless rims and tubeless tires, following pressure and mounting guidelines they are fine. If you slice your tire and develop an unfixable leak, simply pop a tube in to get you home (thats what should have happened with the 23c rider in story above Road Fan )

Fussy is the key, generally tubeless is more fussy / specific increased maintenance for the advantage of less punctures or more grip.

Gravel : 37 C tire I am at 38ps on a 75kg rider,
Road : 25c I am at 90psi on a 75kg rider

But always go by manufacturers recommendation, that is key.

thanks
james
www.buckyrides.com
instagram : @jbucky1

Eggman84

And therein lies the crux. Consider that their are tycially manufacturers; the rim manufacturer and the tire manufacturer. And sometimes there instructions are conflicting, or one or both don't really give instructions. Then their are the bike stores setting these setups and sending people out (like the women on the MUP) with no clear instructions. Even "experts" on this forum can't come to agreement on procedures and compatibility. So yes, by all means convert to tubeless but understand you are part of the learning curve,

Russ Roth

I'm starting to agree with this. I switched mine and my wife's mtbs over to tubeless and so far I'm not fully impressed. Her bike has had zero trouble but then her tires weigh almost 900g, I can do a good tire and tube less than that and might even be able to get tubeless tires lighter. At least hers could be set up with a floor pump but we're not really seeing a benefit to it with hers. My tires were not tubless specific but claim to be compatible and are on stans rims, they really jam into the bead on it but require a compressor to seat the tire. Even at 40psi I've burped the back tire twice so I'm not getting any benefit of lower pressures it seems. Thinking if I run into any troubles I'll put latex tubes in and add some sealant and just save the weight while having a sealable tire.
From my experience so far I'd never bother with road.

ThermionicScott 

Yeah, until everyone gets together and agrees on one spec and set of tolerances (I'm not holding my breath), it's up to the tire installer to make sure the pairing is solid. One good practice I've heard is to mount up the tire dry, pump up to full pressure to seat the beads, then let the air out and see how difficult it is to unseat a bead. If it can be pushed off easily, another layer of tape is a good idea before proceeding with sealant and riding. That would help protect against blowouts as well as having the tire come unmounted if it were to lose air out in the field.

jbucky1

ThermionicScott That practice is a good one, I have done this quite a bit especially when using road / thinner tires and do notice a large difference between manufactures. I think the dry fit is always a good thing to do anyway with tubeless. (excluding mtb)

www.buckyrides.com
ig: jbucky1

NumanR

Ref Jimbo64, I’ve just had exactly the same thing happen, same wheels, same tyres, only I was doing 20 mph on the straight when it happened, no puncture and running 100 psi on the rear. I’m going back to tubes

DrPhyzx

Well... I came across this thread via google search, and several others that are eerily similar, after my own experience.

I've been riding road tubeless on American Classic Argents since late 2014, and have logged 7000-9000 miles a year on them in steep terrain (SF Bay Area): so something like 60000 miles or so. For the first few years I ran IRC Formula Pro Light tires (23C and then 25C), which were light and had good ride quality, but weren't the toughest. I would occasionally get a cut that wouldn't seal well, and even had a pinch once on a sharp stone that was hiding in dappled shade and had to put in a tube to get home. More recently, about 3 years ago, I started riding Continental 5000 TL 25C, which I found to be just as light and fast (if not fasters) but a lot tougher. I have had only minimal loss of sealant with a couple of cuts since then: basically 20000 miles without a flat. I am 165 lbs, and always run between 85 and 105 psi, never less, never more. I have always used Orange Seal, and in the last few years, Orange Seal Endurance, which I have found seals well and lasts longer without drying out and making big gumballs in the tire.

A few weeks ago, I headed out from my house on my shortest loop - 25 mi. / 3000' climb - a ride I do a couple of times a week year round. About 5 minutes from home at 25-30 mph, I banked into a turn I do about 2X as often as that, maybe 200 times/year, turning from one two-lane road to another where the center line one crosses has a center line rumble strip:

commons.wikimedia.org/wiki/File:Centerline_Rumble_Strip.jpg

(sorry, cannot actually post links as new user, but you can search and find yourself.)

While I cannot rule out a stone or other object I didn't see, I ride this so often I likely would have noticed even the smallest thing out of the ordinary. Roughly as, or just after, I crossed the centerline, my rear tire blew out like a gunshot, and I low-sided onto the ground. After sliding only breifly, the rotational momentum of my body in the turn I was executing put my axis of rotation perpendicular to my direction of travel and I started rolling. Rolling turned into tumbling a few times, which resulted in being slammed into the pavement exactly on that spot near the top of my thigh where you can feel the bone (femur) right at the surface. My femur was broken near the top of the shaft, and I've had surgery to insert a Ti rod inside (intramedulllary antegrade nail). No weight bearing on it or riding for 6 weeks. in principle 100% functional recovery is expected (Stanford ortho trauma surgeon very bullish based on my conditioning), but I figure I'm looking at 8-12 months to get back on form at my age (54) with a **** ton of hard work and suffering. Having tumbled more than slid, I had almost no road rash (a few square inches) and my helmet didn't even touch the pavement: not a scratch on it. No other notable bruises even. So, some good luck (no head/neck) and some rotten luck (I smoked my femur, my surgeons words, LOL.)

Examining the bike, the bead rolled off the rim on one side, but does not appear to be damaged. At the scene, there was sealant spilling out, although this was not the kind of event that is likely to get stopped by sealant anyway. The magnitude of the gunshot sound (memorably loud) of the bead breaking tells me that prior pressure loss was not likely a problem - the tire was freshly inflated to 100 psi on this occasion. The tire was mounted 3-4 months prior, so had already seen maybe 2000 trouble-free miles and was still showing tread above the wear indicators, so it was not freshly mounted nor worn out. When I'm ready (and more mobile) I'll do a full inspection of this, and believe me... I am thorough: it's a professional hazard (I am an experimental particle physicist). Frankly, I was half expecting my cursory examination to reveal something obvious I had missed (natural tendency to blame myself - hazard of being a control freak and perfectionist), but it didn't, and now after very easily finding a half dozen stories online that are incredibly similar to the above (although few with my level of injury), I am no longer so sure.

So, why am I writing this? I'm not looking for answers or suggestions, although I imagine some will gladly chime in to tell me what must have gone wrong, or what I should have done differently. I'm also not looking for sympathy: I can get that at home. I'm writing this so when the next person comes along googling for "road tubeless air loss crash" they'll have one more story to consider.

Naturally, being a purist and very stubborn, I started days ago shopping tubeless replacement wheels - I really have like how they run. However, I have a feeling I just won't be able to do that, unless I am able to identify a clear error in my setup or maintenance that I think can be 100% avoided in the future. It'll be hard enough to get back on the bike and go at speed at all. Although I didn't move to CA to ride on the trainer (which I haven't done since racing days back east), it'll be Zwift for me for the first few weeks until I can get my nerve up to get on the bike and point it downhill.

If I learn more on my case, I'll come back and update this.

Cheers,
Tim

Kapusta

I'm going with the "rolled the tire" hypothesis. You might have had a puncture or leak that sealed itself up, but not before losing enough pressure to leave the tire susceptible to "burping" in turn.

Also I would check the taping job on this. If the bead is not tight against the bead shelf, then it is more susceptible to losing air if the bead is briefly unseated.

DrPhyzx

On the first: maybe, but I have broken the bead on a lot of tubeless setups including some that are partially inflated, and this was insanely loud. People that came to the scene from nearby homes actually thought it was a gunshot: this was not a burp, but a complete loss of air in one shot that had me immediately riding on rim. Additionally, I've briefly ridden on 10-20 lbs. in the case of a severe puncture, and unless all the air is gone, I have never had a bead break. So... this "burp" must have released all, or nearly all the air to put me on the rim. I don't call that a burp: maybe you do. In any case, if one can lose 80+ of 100 psi without it being obvious to the rider (sealant spraying on legs - been there many times) then tubeless cannot be safe. There is no sealant on the frame, FWIW, so hard to see how this makes sense. Even small leaks where you lose 10-20 psi always leave a lot of sealant on the back of the seat tube. Please explain why there is no sealant on the seat tube.


On the second: I'm not an amateur with the taping and installation, and it was perfect when the tire was installed. Since I have become more skilled with tubeless, I install dry (and never any tools) and bleed down/remove valve core to check that the bead seats tightly and doesn't slip off when installing sealant. I also check the entire circumference carefully to ensure even seating around the entire circumference. I also always seat with a compressor: a pump doesn't always cut it - sometimes there is a spot where it's not fully seated if pumped up gradually. The tire was never dismounted after this. Also, the tape has nothing to do with "seating the bead on the bead shelf" unless I misunderstand you. I mean, it can leak if not taped well, but the tape cannot prevent the tire from being seated properly - the force there (wall tension per unit circumference) is quite large and the tape serves no function with respect to seating the bead. See also: 1500-2000 miles (and probably 80 rides through the same turn on the same tire) beforehand. I take this turn on at least 2/3 of my rides every year. Also... I was not cornering particular aggressively: I was already pedaling (so within pedal clearance) when it blew out.


Next! (I fully expect everyone who rides tubeless to show up with the idea that it can't happen to them, because they are too careful. Would have been me a month ago to: I am insanely - perhaps infamously - anal with this kind of stuff at home and at work. But, people listen to me because I am too often right.)

Kapusta

If you are running enough pressure to avoid snakebites with tubes, then you are running WAY more than enough pressure to avoid burping a tubeless tire.

Kapusta

You are under a few misconceptions here (including what you think I am referring to in the taping job), but you make it pretty clear that your are not that interested in hearing about it.

Good luck with whatever you decide to do here.

DrPhyzx

Do tell. Perhaps you have simply not made your points clearly.

I have edited the last post for more clarity on the points you raised.