The tires probably did make a difference in your tests (I'm just guessing). Both Mu P8 and Speed P8 are nice bikes, I think. (The Dahon P8s have better components than the Tern D8.) Aside from being chromo, the P8 comes with Big Apples, so that will probably help give you a smoother ride also. You can always switch bikes with your wife if she finds the Speed a bit long (and also change the Mu's tires). The Mu is the lighter bike, anyway, so easier for her to handle.