I have 3 spacers in my headset and I'd like to remove 1. If I do, the stearing tube will stick up higher than the stem; there wont be a proper gap for the stem cap to compress the headset properly. I assume I have to have the stearing tube cut/faced. ? Is this something I can reasonably do at home?

Also, how do the manufacturers decide on how many spacers (how much space) to put in the headset?

Thanks!

What does the LBS base the spacing on? Do they cut the steering tube to the appropriate length?

A good LBS will cut the steerer to the customer's requirements. Many will cut them as long as possible to safely have a maximum number of spacers (carbon steerers have a recommended maximum) and then shorten them later as requested.

I agree that putting the spacers above the stem is the best short term method. That way if you change your mind you can put some or all of them back below the stem.

Cutting a steerer is a pretty straightforward procedure. A sharp fine tooth (32tpi or more) hacksaw blade and cutting quide (a stainless steel worm clamp is a good one) are all you need. Steel and Al steerers are easy but carbon requires a bit more care.

Remember, once it's cut there is no going back so be SURE you have the length you want.

Thanks for the answers/advice!

I like to use a plumber's tubing cutter. On my touring bike I have 3 spacers below the stem, and two above. Lot's of room for adjustment.

When you take the spacer out of the bottom, put it on top and then put the back cap on.

lets say you have 3 spacers. take 1 out. now put your handlebars on top of the 2 now put the other 1 on top of your bars.