ATC 90 front rim/tire help

[bmw1]

The 90 I have has knobby tires on it all the way around.

The front rim does not appear to be a split rim. The rim only has 3 bolts for the hub and that is all.

I cut the tire off because it wad dry rotted so bad. It had a tube in it as well. There are also what looks like o rings next to the bead. They are the thickness of a small belt. The rear tires did not have this "ring" next to the bead when I replaced those and the rear rims did split.

It doesn't "look" like the front rim can be split. Is this normal? Is there a procedure for changing these tires? Does the front require a "special" tire?

The frame indicates a US90 so I think it may have originally had the balloon tires. Someone put the knobby tires and split rims on and I have no idea what kind of machine they came from.

Thanks.

[coolpool]

I believe those are just there to strengthen the original OHTSU tire beads. You should be able to mount an aftermarket tire back on there with no issues.