Wow, they reinvented the screwdriver.

The problem with the Marathon isn't that it is particularly tight on the rim, but that the bead has a bad habit of popping back out after you push it in. But, I did manage to get a 25mm Marathon mounted on my Aerohead rims without any toestraps, or tools. After the first time I removed it, it was much easier to get back into place (or I was getting better at it).