I'm not one to disagree usually as I generally feel that everybody is allowed their opinion. However, I must disagree about using a crescent wrench to tighten track nuts. The force required to tighten them enough is more than a crescent (adjustable) wrenche is made for. The tolerances on all but the highest quality ones are just terrible. I tried loosening a track nut on my bike so I could flip the wheel over for a long hill climb (I had forgotten my 15mm wrench at home, that's another story) and I wrecked one of my track nuts completely when I tried to use an adjustable wrench I had on me.

I feel that a closed ended 15mm wrench will work perfectly, and that there is no substitute for it.