Big Bird wrote: I sort of gave up on tubes and tubeless system years ago and now just run both (On my DH bike that is. I don't currently have a trail bike.) I've got Mavic tubeless rims and tubeless tires, then run a tube inside with the Mavic o-ring seal on the stem. That way if I hit something hard enough to pinch the tube, the tubeless system still holds the air in. And since there's a tube in there, burping is no longer a problem. The main drawback is that you sort of have to take the whole thing apart to check if the tube is still intact, which I never do.
Back in the 3.0 tire days, I overheard a racer complaining to his buddy that he'd increased his tire pressure from twelve to eighteen whole pounds of pressure and was STILL getting flats. For me tire pressure is what really saves me from flats. For me, flirting with low pressure means only running thirty pounds, which is how much Peaty runs. I'm taller and I'd guess heavier than him, so I generally run thirty five in the rear. It may not make for the BEST traction, but I hate the squirmy feeling of low pressures anyway.
And that little o-ring is supposed to hold the air back in the event that the tube suffers a pinch? I'm totally baffled by this concept.
I tried tubeless on some stans flow wheels, and could not find a tire that would hold on. UST tires, 2ply dh tires, TCS, from all kinds of brands. After enough ruined rides, and one ruined race, I gave up and put the tubes back in.
My best flatless setup begins with my favorite rim, the Spank Subrosa. The center of the rim is raised and it results in fewer pinches, one time I dented the rim testing a rock landing, and rode away without a pinch flat.
The next crucial aspect of the setup is a DH casing tire, on the rear I've been running a clipped Conti Mud King for about a year now. It is difficult to find a tire narrow enough for xc climbs (2.3-2.4), but with a DH casing for durability. The mud king is great, so is the Larsen tt 2ply. I really wish Maxxis would use the DH casing on their 2.35 minions again, that would be the Balls.
In my experience, single ply tires fail in two ways; first they suffer pitch flats (even at 60psi), then they blow out the sidewall. Wearing a $70 tire's sidewall out before the tread is a waste, so I don't run folding tires on my mtn bike anymore.