Hello Keith:

If the leaking is from the junction of the tire and the rim, the problem must be caused by damaged tire rubber, tiny pin hole or small crack are exist in this area and cause leaking. Changing new tires will solve the problem.

If you can see bubbles from nipple in water, the leaking is from the 42mmX3.5mm O-ring which acts as a check-valve. Taking it out and lubricating by thick silicon oil and assembling it again will solve the problem.

The 50mmX1mm O-ring is just for sealing two half of rims, it is only functional when you are inflating the tire, so it will not cause tire leaking.

Please send me your address for sending new tires to you.

Best regards