Flat Front

[CeeJay07]

Did they actually take the tyre off the rim? As an ex-tyre fitter, it only takes a miniscule particle to disturb the seal at the tyre bead. Try pumping your tyre up and spray soapy water around the edge of the rim (works better if you can get the wheel off the bike and lay it flat)...or submerge the whole thing in water...then watch carefully for bubbles.