Originally Posted by
dwainedibbly
Not if you push the valve stem in a little so that the bead can get underneath it.
Yup! Seat the bead with the fat part of the tube, where the valve is, first, then work around t' the opposite side, and dismount conversely.
Pushing the valve stem up a bit is critical! At the last bit, as per OP's picture, I hold the rim with my toes, and run finger around to be sure the bead is off the riser at the edge of the rim, then ease 'er over.
The wipe of spit on that last bit usually does it, such that tire iron is not necessary. However, I've found my front tire works around unless I use the thicker cloth type rimstrips (I use the lightweight ones on the back, which gets braking and "awesome" power...), which makes it harder to mount/dismount the tire; there is less room!
Don't forget to wet the last bit!
Around here, when the puncture vine has had a "good" year (like 2006, yikes!! '07 wasn't so bad), one simply must be proficient in tire & tube maintenance at roadside and trailside! ...ask cccorlew