Tire and Rim combination blowouts

It was discussed that it might be helpful to have tire/rim combo data regarding blowouts.

This is a simple google document spreadsheet, in case others think it is convenient. Of course, open to ideas!

I am adding one now unfortunately.
Alchemist 36" rim. New Nightrider Lite Tire. Tubeless.
Blew at 42 psi.

I had set the bead by inflating with a 29" tube, letting it sit for a few hours.
I popped the bead off of just one side to take the tube off. It was extremely difficult to get the bead off! Put all my weight + extra hand grip force to get unseat it. Once it was in the channel of the rim, it was quite easy though.

I thought that given how tight the bead was, it would be okay tubeless.

I could not get it to inflate with just my ghetto compressor (garden sprayer). So, I used a tire lever to seat half of the remaining bead. The last half seated well with the compressor now.

Pumped up to 40 psi, andI measured the spoke tensions. Then I left it overnight. Next morning, the air had leaked out as expected, since I didn’t add any sealant yet. Bead was still all seated.

I pumped it right back up to 42 psi because I wanted to test the spoke tensions again. However, within a few seconds of being at 42 psi, the dreaded bang. I had took out my ear protection but didn’t wear them since I thought it was relatively safe after holding air the previous night…

The side that popped off was the 2nd bead I had set using tire levers. This means the tightness was definitely uneven. Whether or not having an even bead tightness would help or not, I am not sure. Maybe I will try setting the 2nd bead with soapy water instead of a tire lever. Also might need a few layers of tape to make the rim channel a bit tighter to help.

It is already been said: Nimbus 36 rim and 36er Nightrider/Quax/King George tires match each other and they are all “out of specs related to bicycle’s standard”. Instead Alchemist, Nextie rims and Vee Tire tyre match each other and they are all “compliant related to bicycle world standards”.
I wrote it because I cannot understand your rim comment on the file.
However: +1 to your exact combo. I had the tire blow in a sudden uphill ride

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I had read much about Nextie rims and tire blow outs (with tubes).

I had not seen much with the Alechmist rims, so I thought they would work well enough to be tubeless.

Of course, given these 36" tires are not tubeless compatible in the first place, that definitely contributes to blowouts with tubeless setups. However, if they also blow out with a tube, then I wonder what exactly is the problem.

My comment about the rim in the spreadsheet is that the rim is too light (~540 grams). So, it is very likely that mine is weaker than a “normal” rim.

Did you switch to a tube and have been problem free since?

I might actually try tubeless again later, at 20psi for offroad.

I don’t think that should be accepted as true. Nextie and Alchemist produced a rim for which none, zero, zilch compatible tires exist on this planet, period. There are no tubeless ready 36" tires. That’s the problem. The Vee Tire seems to have worked pretty well so far but I would not be surprised if a Vee blowoff has (or will) occurred.
I direct my frustration directly at Nextie and Alchemist for not working or collaborating with current tire manufacturers to produce something really compatible. Those companies are irresponsible in my opinion.

I think a lot of the problem is that unlike “normal” bicycle sized rims/tires there is no world standards for 36" tires or rims. You would think that a 36" standard should be developed but because of the very low demand for that size it has not been done yet.