Originally Posted by
Skankingbiker
Based on others' similar conversions (detailed on bentrrider), the smaller wheels spread out the wheelbase and make the handling more stable. It also adds more weight to the front, which is good for the FWD on hills..
Just to address this, which i didn't do before:
The wheelbase is set by the frame. For a large rear wheel, the frame must use longer stays, which increases bike length and wheelbase. If the frame is disc-capable, you can put a small wheel on such a frame, but it doesn't change the wheelbase. Smaller front wheels are usually done for one of two reasons: 1. keep the height of the front end a little lower, and 2. if it's a short wheelbase bike, then there's less wheel to reach past to the pedals. So, for a given frame, wheel size make no difference in wheelbase. And if the frame is designed for small wheels, it will have a shorter wheelbase, not longer.