Bicycle Mechanics - 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.

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.1) The bolts don't matter. 2) The star nut and topcap are critical to adjusting HS bearing preload. Suggest you go to repair sction at www.parktool.com and read up on HS and adjustment before buggering something or hurting yourself. 3)Eyeballs work, except when full of too much beer.

www.parktool.com

Great info there, thanks.

Theoretically once you have the preload set and the stem installed and torqued down you could remove the top cap and punch the star nut out through the bottom of the steerer. It's the stem that holds everything together. I've never seen this actually done, though - seems like they provide at least a small safety factor...........plus you'd have to reinstall if it ever loosened up or you needed to pull the stem for whatever reason.

[QUOTE=GV27]Theoretically once you have the preload set and the stem installed and torqued down you could remove the top cap and punch the star nut out through the bottom of the steerer. It's the stem that holds everything together. I've never seen this actually done, though - seems like they provide at least a small safety factor...........plus you'd have to reinstall if it ever loosened up or you needed to pull the stem for whatever reason.

Leave the star nut and cap on; if you need to make an on-the-road repair or adjustment you'll be hosed w/o them.

3)Eyeballs work, except when full of too much beer.

!edit: I tried to put an icon of phil from harvey birdman here... and it didn't work :(! Hah hah haaahhh! "Balls".

sorry, I totally imagined a phil laugh there :B Anybody else here be harvey birdman fans?

anyhoo, I wanted to say that I use the same method when aligning my stem... sober, ov coarse ;)