Is there a difference in rim size? I’m trying to mount a Schwalbe S One on a BOR 388 rim. Initial tubeless attempts were messy and futile. I’ve now got a tube in there and there is a very noticeable hop in the tyre, you can see a 150mm section where the bead is still sitting in the central chanel of the rim. Searches invariably say that they are the same but it’s not looking too clever just now. The tyre is quite wide 30mm and the rim is narrow so I wasn’t expecting this to factor.

They’re the same diameter.

The rims are the same.
I have had out of round schwalbe tyres, maybe try swapping the tyres around and seeing if the problem follows the tyre?

Deflate the tube and debead the tyre, spray silicone or use a smear of washing up liquid round the tyre bead and reinflate to maximum rated psi, or just slightly over and it should pop into the rim bead then deflate to your preferred pressure. Ride it as it is with a tube for a couple of days then try to set up tubeless.

Cheers, I’ll have a bash with the lub and tube. I did try a bit of hand wash around the inside of the rim when trying to inflate tubeless. As I released a shot of air it spaffed everywhere, unfortunately it bore more than a passing resemblance to manmuck. I had to frantically check myself for a Something about Mary type deposit as I had to leave to pick the kids up from school.

I had the same problem with Schwalbe S Ones, no matter what I did I could not get them to mount evenly on my 700c American Classic rims. I had Schwalbe Ones on before, which went on with no problems… I ended up sending the S Ones back