Touring - stem question

hi all,

sorry to post what might seem a pretty obvious question - novice at play here.

i've just changed the stem on my trek 520 for a steeper stem than the stock one however at the point at which the stem attaches to the upper extension of the forks this new stem is longer (vertically) than the old one. as such there is now a need to remove one of the spacers if i want the entire attachment to be on the fork extension rather than being partially on the internal shim only.

is it unsafe for me to keep it as suggested above without removing one of the shims (thereby lowering the stem position and kind of rendering the whole change redundant)?

cheers.

Spacers used with threadless headsets are meant to be added/subtracted to adjust the height of different stems. So -- if I understand your description correctly -- you can and should remove a spacer or two to make the new stem fit.

But this part of your post sounds dangerous:

is it unsafe for me to keep it as suggested above without removing one of the shims (thereby lowering the stem position and kind of rendering the whole change redundant)?
If you're thinking of mounting a new stem with a different stack height, and without adjusting the spacers, you're taking a chance on catastrophic failure. See the Park Tool site (http://www.parktool.com/repair/readhowto.asp?id=65)for proper installation (near the bottom of the page).

Spacers are made from 1mm to 20mm height. Check with your LBS if you need to jigger your stack height with a new spacer.

-- Mark

the steerer tube (fork extension) should come to about 1 mm below the top of the stem. Adjust the spacers accordingly.

thanks folks, i rode it into work today and it felt fine but then i did the "hold the front brake and wobble" test and there's a lot fo movement so i'm gonna take a spacer out to get it to the height that supcom suggested to avoid a nasty incident - thanks again, i was pretty sure i was doing the wrong thing.

Once you have the spacer height correct, just make sure you then get the headset bearing preload right to get rid of that "hold the front brake and wobble" looseness.

Just wanted to make sure you are aware of that. Not going to try to explain it as you may already know.

Bruce

If it's wobbling, chances are you don't have the bearing adjustment correct. Riding a loose headset is the quickest way I know to ruin it.