Stem angle and bar height question

[pakora]

Setting up the old cross bike, and whether it's losing a bit of the ol' midsection or throwing down in some crits this year, my bar height on my race bike feels high, so I'm going to experiment with height a bit.

Since I have a 6 degree stem flipped up, it occurs to me that I can microadjust reach and height a bit by messing with spacers and whether the stem is flipped up or down.

Is there a functional difference for flipped up or down, assuming the same bar height? Something something mechanical advantage? Or perhaps something something leverage something something?

I'm guessing not, besides making my opponents shudder and fear for the 39th place they thought they had in the bag when they see my stem flipped down and spacers on top of it.

The stem is 140mm and there's 20mm of spacers below it currently (maxing out bar height on this fork) above a 175mm ht if that matters.

[rnhood]

Generally speaking, the steerer tube integrity is higher if you flip up the stem since there will be less spacers.

The more spacers, the more lever arm which means less force to the bars or stem to damage (crack, break, etc) the steerer tube.

So to answer your question, flip the stem up. If you have to have the fashionable flipped down look, then its really not a concern since you are only using 20mm of spacers. I think most bike/frame vendors say 30mm is the max spacers allowed (on a carbon steerer tube). You are well under that.

[ultraman6970]

The only difference i have noticed is handling, depends a lot of the rider too, some guys cant handle even riding in a colnago and those pretty much ride by themselves. If you slam the steering will get more solid anyways.

As for differences flip or unflip will give you a difference of maybe 5 to 7 mm depending on the angle? is not even that much as many people think. Stem going down should give you more room in the front, the bike will get more assertive, handling will be better, more weight in the front, handling, handling handling.

If the hands are ok, you have no back issues just slam that thing and see how it feels, sure the 1st thing you will notice is that the bike feels more planted over the pavement.

Stem up, well no coments, never understood too good why stores set them up like that when clearly the bike feels shaky, looks like people likes to ride shaky, it helps to sell bikes :P

[pakora]

This is a steel steerer as well, so even less concerned with integrity.

I forgot how bad my head is at bike geometry. Flipping the stem without removing spacers is still lower than flipped up and losing all of them, despite the shallow angle!

Looks like I'll be just removing spacers one at a time, as it doesn't feel dramatically high, just a touch.

Ah the stem calculator, what did we do before you?

http://alex.phred.org/stemchart/Default.aspx

[Ralph]

I'm an old guy, but I want mine as low as I can ride comfortable. You go faster. I ride with 10 CM of drop from seat height to hoods. Can still use drops that way. Admit....can't ride as low as in past.

[CiclistiCliff]

higher bars. more leverage for bunny hops.

[Mark McM]

Generally speaking, the steerer tube integrity is higher if you flip up the stem since there will be less spacers.

The more spacers, the more lever arm which means less force to the bars or stem to damage (crack, break, etc) the steerer tube.

Well, not quite true. The bending moment in the steerer depends only on the position handlebars relative to the headset. It doesn't really matter whether the stem is flipped down with a lot of spacers or the stem is flipped up with fewer spacers. The fork manufacturers recommendation for a maximum number of spacers is really just a crude attempt to limit the handlebar height (and therefore the moment arm for bending forces) than any problem caused by the height of the spacers.