Inflating the tube will pull the valve into the rim. Fully deflate and push on the valve through the tyre. You may be able to get some more leverage on the screw when there's more exposed.
@pifko started
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Inflating the tube will pull the valve into the rim. Fully deflate and push on the valve through the tyre. You may be able to get some more leverage on the screw when there's more exposed.