How to fix tubeless tire leak at rim seam

Question

I bought a Cannondale Fat Caad 2 that came with tubeless ready rims and tires— the rim is even pre-taped. I’m converting to tubeless currently — removed tube, installed valve stem, put 120ml of sealant in the tire, inflated the tire to 30 psi to seat it, rolling the tire.

Testing with soapy water, it’s sealed everywhere except for at the rim seam. It’s actually leaking through the seam at the groove where the small bubbles in the picture are and slightly at the bead where the big bubbles are.

Will this seal after rolling the tires for a few days or should I open it back up to do something, and if so, what?

Answer 1

The fix ended up being very simple. After inflating the tire to 30 psi to seat it, I decreased the psi to 15 and rolled the tires like normal over the next couple hours. Then I dropped the psi down to my running pressure of 5 psi.

The problem simply seemed to be that 30 psi was too high while the sealant was sealing the gaps. 15 psi seemed high enough to push it into the gaps and low enough to let it seal.

Answer 2

The only solution that I've found for this is to put in a thicker sealant along with the one that you're already using. The two that I've had the most success with are Finish Line and Never Flat. I've never had an issue mixing this with any of the sealants that I've used before.

If this doesn't fix it, then unfortunately it's just a matter of not using that particular rim/tyre combination. Some tyres just don't play nicely with some rims and there's no way to make it work.