Only concern is will she face plant every time she hits the front brake at speed?
Not if using fixed, the resistance of the feet/cranks does not allow your body to fly over the bars (well it shouldn't).
However, braking and skiding at the same time, now that is guaranteed flying.
Regarding the 650 front and wheel, .... I wouldn't, it will alter the frame's geo, lower the BB, etc, etc...
Why not selling the BJ, and getting something right?
Not if using fixed, the resistance of the feet/cranks does not allow your body to fly over the bars (well it shouldn't).
However, braking and skiding at the same time, now that is guaranteed flying.
Regarding the 650 front and wheel, .... I wouldn't, it will alter the frame's geo, lower the BB, etc, etc...
Why not selling the BJ, and getting something right?