Question on threadless stem attachment
Hi all. I'm new to threadless stems. I just got a stem from Colorado Cyclist in the mail last night to replace the one that came with my bike, trying to get a better fit. I have three questions about mounting it:
1) The old one had the bolts that attach to the steerer tube running in opposite directions (one from the left, one from the right). The new one has both running from left to right. This seemed odd because they're the exact same model of stem, just two different lengths. Does this bolt pattern make any difference?
2) What purpose do the "star nut" (I hope I got that right -- the little star-shaped dealy that's wedged inside the top of the steerer tube) and the small cap over the steerer tube serve, other than cosmetic or keeping water out?
3) When aligning the new stem, are there any tricks to getting it centered? I pretty much just eyeballed it against the front tire.
Thanks in advance.