Originally Posted by
zacster
The trick is to not do the last bit opposite the valve but at 90 degrees to it, and have the opposite side as far into the middle groove as possible to give you just a little more length to get over the rim, and that goes for taking off or putting on. The valve prevents the tire's bead from going into the center groove.
So you are saying that doing the last part 90 deg to the stem gives you a bit more slack to finish? Makes sense. I'll try it that way next time I mount a tire. I've always done the last bit 180 deg from the valve and have only rarely had to resort to my VAR tire jack so I've either been lucky with tire/rim combo or I have strong thumbs. Nevertheless, I look forward to encountering a difficult mount so I can try your method. I volunteer at our local bike co-op and typically do a couple of mountings each week.
Thanks for the hint.