Tom L

yesterday I was busy in the morning doing some maintenance on my bikes, my mountain bike needed some more sealant
so I emptied the air on both, added my sealant, and like every time I have done this fill the two tires up to 55 lbs., tires are vittoria 29 x 2.25
tubeless ready.tires are rated on the sidewall to 60 psi, I had 55 in them to get the sealant to set.
I moved off to the side to get something and the back tire blew, like a cannon going off, completely took the rear tire off the rim. it was around the frame, all the sealant everywhere,


I wound up putting the tire back on, don't have a spare, re seated it with the compressor, and then filled it to 40 lbs and it holds air
I can't figure how that tire blew up like that, it was fine for 10 minutes than kaboom
my ear is still ringing

do you think this will happen again? is the tire shot? it was tough as usual to put it back on, rims are WTB non hooked from lights rims

anyone have experience with a tire that has blown and then was ok after remounting

blamester

I don't have experience with tubeless but it didn't happen for no reason.
Overinflated, incorrectly installed , tyre damage or rim damge. It must be one of these.
So have a look at it and if there is no damage reinflate and let it sit for a while.

Andrew R Stewart 

Most likely the tire's bead wasn't seated fully. It took a few minutes to work it's way up and off the rim. I also suspect that the sealant acted like a lube between the bead and rim.

This had nothing to do with being tubeless and everything to do with how the tire was mounted. Tube types do this too. Andy

AlmostTrick

I thought for sure this was going to be a carbon fiber asplosion thread.

True, but being tubeless had everything to do with "all the sealant everywhere".

Completely eliminating the possibility of experiencing a sticky sealant mess is a valid reason not to run tubeless.

Tom L

really seems odd, this bike I haven't ridden since september, it hangs from the seat post when stored, tires still had 10 lbs in them after all that time
all I did was remove the stems add sealant and re pressurize, hopefully the 40 lbs holds and the tire is OK

lucky for me it was a nice day outside and after I gave the bikes a bath I was working on them in the driveway, that would have been a real mess if it
happened in my work room in the house, or in the garage for that matter

Iride01 

Anytime you change a tire, inflate a nearly flat tire or just in general, a quick glance at the witness lines on both sides of the tire will let you know that the bead is seated. If one of the witness lines is below the edge of the rim, then it is possible to blow the tire off the rim if on the opposite same side the witness line is way too far above the rim. I've done it myself with tubed tires. And yes it is quite loud. There is a pretty good volume of air suddenly being released.

Bikes that are left unused for several months are prime candidates for having their tire beads unseated if rolled to get them out to where their tires are inflated. Usually no issue, the bead simply jumps up on the seat with a pop or cracking sound. But not always.

DiabloScott

Or a carcass failure, but that would have been obvious.

cpach

From a WTB rim manual:
"With noticeably wider WTB rims, as in the case of the WTB Scraper i45 27.5” TCS Rim, WTB Scraper i45 29” TCS Rim, WTB Asym i35 27.5” TCS Rim, and WTB Asym i35 29” Rim, please ensure that when mounted in a sealant-tubeless fashion, the following pressures, listed in pounds per square inch, or psi, are strictly adhered to: Minimum: 20 psi Maximum: 45 psi Regardless of the tire’s recommended pressure ratings, Scraper i45 27.5” TCS Rims, Scraper i45 29” TCS Rims, Asym i35 27.5” Rims, and Asym i35 29” Rims will need to fall within the 20 – 45 psi recommended range. Narrower tires, fewer than 57mm in Section Width (SW) will need to fall toward the higher end of the 20 – 45 psi recommended pressure range."

55PSI is way too high for a modern mountain bike rim set up tubeless. Tubeless places significantly more stress on the rim than a tube. I never exceed 40PSI on any tubeless MTB setup when setting up tubeless as a professional mechanic for this reason. I would never send a customer out on a tire that blew off the rim as the bead is likely compromised--you should replace the tire, and stop inflating to such high pressures.

shelbyfv

I did this as well, user error in a couple of ways. I usually ran the tires at 40 but pumped this one up to 55 or so to seat. Also, it was cold in the garage so I took the wheel inside and set it near a heating vent so the sealant would stay fluid until it got wherever it needed to be. Thankfully I was in another room when it exploded. It was very loud! The tire was on one side of the room, wheel on opposite side and sealant everywhere including the ceiling. It was hard to see but the tire bead was damaged. It wouldn't hold a seal tubeless and even with a tube it didn't sit evenly. Newish GravelKing into the trash.

Pop N Wood

A life that doesn't occasionally require dealing with a sticky mess just isn't worth living.

Not a bad practice to fill a tire incrementally in pressure massaging and inspecting the tire bead as you do so. In fact with tubes I run the pressure up and down several times while working up to full pressure to help take possible kinks out of the tube.

Realize tubeless tires may want a quick shot to seal, but should still be able to build up in pressure a bit at a time.

yeah, tires can go off like rifle shots at times.

Pirkaus

55 psi to start, nice sunny day outside, black tire + sunshine=KABOOM
Had this happen on a tubed tire in the back of my pick up truck, shredded the bead
I would not run that tire, we want to keep you around