No, it won't. The NC30 and MC28 both have larger diameter swingarm pivots, so the MC21 frame will need to be reamed out for it to fit.

You should then be able to fit it using MC28 spacers etc. The MC21 and MC28 shocks are the same, so it won't be too much of a job after the frame is modified (unlike converting the MC18 to Pro-Arm... big job, before anyone asks!!).

Just out of interest, why do you want to swap the lighter, stiffer Gull-Arm for the heavier Pro-Arm? And why would you swap the MC21's 17" wheel for a heavier NC30 18" wheel, or do you have an MC28/RS250 wheel?

Moving this topic to the "Discussion" page.

Andy.
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