-
I don't have any Bonty rims, but I have some old Light Bicycle 'Bontyesque' rims which use the Bontrager plastic rim strips. If they're the ones I'm thinking of, the only possible leakage point is the valve hole as rather than tape it's a moulded plastic rim strip which curls up around the rim beads. If the tyre's seated against the plastic rim tape, there really shouldn't be any way for the sealant to escape other than the valve hole.
Brommers-
When I pulled the strip off it got all stretched and distorted because the sealant and oxidisation was effectively gluing it to the rim.
I hoped putting the tyre on with a tube might flatten it out but it didn't.
I'm slightly worried a new rim strip won't seal properly because between some old hardened sealant and bits of oxidisation the surface is a bit uneven in places, especially up in the bead/hook kinda of area.
The strip is less than a tenner so it's worth a shot I figure.
M_V
Nah, wheel didn't come with one so I used one I'd bought from Cycle Clinic.
I suspect the air was getting around the wrinkled and stretched rim strip, through the spoke holes into the cavity and the valve hole was the easiest place for it to escape.
Triton have a rim strip I hope will work so probably going to order that and see how I get on.