Never had any issues until now – my new Ron/Ralph combo is so loose at the bead (on American Classics) the air just blows straight out.

They are currently sitting with tubes in overnight to stretch / shape them – if they don’t go up tubeless tomorrow what else to try?

The trick that’s always worked for me when a tyre doesn’t want to go up is to pop the bead on with a tube and remove the tube, leaving one side of the bead in place. Then, pop the valve in and the other side should pop into place fairly easily. Give it a go.

^^^ +1, just tried that a few hours ago when a new continental x king refused to go up. went up in seconds after seating one bead using a tube.

^^+2. Worked for me too earlier today. Putting an Ardent onto a WTB 23i rim. Went out for a 2 hour ride and all worked well. So satisfying.

I’m always a bit wary of tyres with loose beads when running tubeless, I’d build up the rim diameter with a strip of electrical tape to give a tighter fit. burping or rolling off the rim is not a good thing, especially on a front tyre.

Well, the Ron is on after sitting overnight in a combo or tube and Stans. The Ralph with tube but no stans failed, therefore that’s had stans added and pumped back up with tube so lets see if it seats.

I used CO2 the first time, not recommended apparently but I never had a problem. Pulled a thorns out over the last 12 months and never had a flat.

They go up fine these days with a track pump…