basically, the rear hub is wider than the front hub. so the angle is different. i took a yz250 wheel, and a dr650 front hub, dropped it off at the wheel builder and picked it up 5 days later with stainless steel spokes laced in it. i rode it for a year, then i upgraded to a set of warp9 17x4.25" rear, 19x2.50" front wheels on my dr650. i sold the wheel to a buddy, he's been riding on it since 2016. i guess it works. i don't know what spoke nipples were used, but there's never been a problem. is it correct, no, could it fail, sure. would i do it again, absolutely. the issues isn't really where the nipple is into the wheel, but the bowing of the spokes, and not being able to get the tension correct etc.