Cramic

Fixed my first puncture on my tubeless tyres. (It’s a Giant Gavia Course 1 if that makes any difference, rear tyre.)

Not a huge puncture and I thought ideal for my first one. Used the smaller of my Ryder plugs, refilled with the sealant (Muc-Off No Puncture), reinflated to somewhere around 80-100psi (I usually inflate to 80, but sometimes overshoot to 90) and patted myself on the back for a job well done.

Few days later, a total of around 20km since repair, it failed catastrophically. A very rapid deflation and sealant sprayed everywhere.

I happened to be very close to home so I just walked it in, put it in the shed, and have just come back to fix it now (a few days later).

To find the puncture (pictured) I re-inflated to 80psi. I could hear it, on the ground side, but as I rotated the wheel it stopped. It had sealed itself with whatever sealant remained. Then it started hissing for a second, I rolled it back to be ground facing, and it stopped. It’s still sealed now, 20 minutes later at 80-90psi.

I’m pretty sure it’s the puncture I fixed, mainly because I can’t find another one with a plug in it, although I did think the one I fixed was on the other edge of the tyre.

So:

1) Is it common for plugs to fail? And, if so, when?
2) Why did the tyre seal itself just now, but not at the time? (It’s dry now, but I was cycling in the wet, if that makes a difference?)
3) Any tips for plugging that would improve long term success? I get maybe a bigger plug, but the larger plug looked too big for the hole and the smaller seemed to do the job.
4) Tips for subsequent management of a plugged tyre? Ride lower pressures? I’m a heavier cyclist (100kg.)

Thanks for any tips/advice! Please see attached picture of the sealed puncture.

Crankycrank

Just guessing but that cut looks pretty large for a plug especially if you used one of the smaller ones and cuts are harder to seal than round holes plus combined with having a high pressure tire your odds are not good for a long-term fix. I would recommend using a proper inner patch which should last the life of the tire.

grumpus

Consider plugs to be a trail fix for damage greater than your sealant can handle, and reckon on patching the tyre at some point.

Schweinhund

This ^
Car tires in comparison to bike tires are of much heavier construction. In a car tire it's considered a temporary fix because in order for it to work it's got to be forced into the hole. it moves stuff around inside that's not meant to be moved. They are not approved as a long term fix.
Even less so in a tire that has much lighter construction than a car/motorcycle tire.

CrimsonEclipse

"What did I do wrong?"

You went tubeless.....

urbanknight

This. Some companies even recommend replacing the tire after a cut that large. Other thoughts:
My first (and hopefully last) failed plug was from not twisting enough before pulling the tool out. I can't tell you how long my successful plug would have lasted because I replaced the tire 40 miles later.
Another thought is that those are junk tires in my experience.

tyrion

I've never seen a plugged tire in real life but I would expect the plug to be visible in the puncture if it was plugged.

GhostRider62

I see a big hole and no plug.

I've only had to use my Dynaplug twice so not an expert. There is a rubber tail from the plug that hangs out of the hole, I trim it. But the plug is still obvious. I don't see a plug on your tire. That is a big hole. Not sure a plug will work? I had a smaller hole on a 600km brevet and the plug worked but I junked the tire afterwards.

maddog34

you chose to carry a temporary plug kit, and a bottle of messy liquid, instead of a spare tube.
tip: carry a spare tube on your next ride.

Reynolds 531 

I always patch the inside of the tire when I get home. I usually use a small automotive "radial tire" patch. (radial tire patches have a direction to them to align with the carcass threads)

well biked

In the world of tubeless tires, that's a very high pressure tire. Running the kinds of pressures you're using, I think using a plug for a repair is just generally not going to be reilable. Plugs often work great on tubeless mountain bike tires and tubeless gravel tires, but tubeless mountain bike tires are often run at pressures in the teens, certainly below 30psi. Tubeless gravel tires, generally speaking, maybe high twenties to around 40psi. With the higher pressure tires like in your photo, I suggest repairing punctures out on the road that don't seal with sealant with a spare inner tube, and then if you want to try and salvage the tire later, try a patch on the inside of the tire if feasible.

Canker

Dyna plugs for road bikes. Regular old bacon strips are fine for mountain bikes but for higher pressure I want something more secure.

Atlas Shrugged

Try DynaPlugs and that should take care of it. I run tubeless on all my bikes including my touring bike, I had a cut larger than that one that needed the large plug to seal and rode an additional 1,000 km on that tire without an issue only to replace the tire when I got home. I trimmed the excess off the plug though.

Mtracer

Another vote for Dynaplugs. They have a metal tip that stays in the tire and helps to keep the air pressure from pushing the plug out. Also, 80-100 PSI is almost certainly too high a pressure for optimum rolling resistance. You might want to try a tire pressure calculator. I like this one from Silca:
Silca Pressure Calculator