When I don't slam my stem i have 3 spacers under the stem but when I do i can only fit 2 on top of it? Did i do something wrong and is this dangerous?

Sounds like your stem isn't all the way on when in the non-slammed position. Normally you'd need the stem to stick up just a few mm past the top of the steering tube in the non-slammed position. Seems like you may have much more empty space than this.

Pics would help though. Can you post one with the stem cap removed?

unslammed 3 spacers
slammed 2 spacers

You need to get rid of the conical spacer on the bottom if you want to slam it all the way down. I believe slamthatstem.com sells the parts needed to do that. Specialized doesn't recommended running spacers on top of their carbon steerers (you can do it temporarily though.) I should add that I'm in the camp that thinks slamming a stem for looks is not a smart move. I would recommend that you don't cut off that steerer tube until you know you can comfortably ride the bike that way.

if you have only three spacers (and they are of the same dimensions) and can put them under the stem, you should be able to remove them from under the stem and put them on top too. or put one under and two on top. or two under and one on top. remember your stem is just another spacer as far as your steerer tube is concerned.

of course if when you have all the spacers under the stem and the gap from the top of the stem to the top of the steerer is more than one your aforementioned equally dimensioned spacers, well, then all bets are off.

Yes, it sounds like the steerer was cut shorter than optimum for three spacers under the stem, but whoever set up the bike thought the stem needed to be lifted that high. No matter if you want to ride on lower bars. Just discard the extra spacer immediately, but be sure to cut the steerer properly if you decide to get rid of all spacers. Once it is too short with no spacers, there is little you can do to fix it. And as recommended above, don't cut until you are sure you like the new position. In case you decide to raise the bar again, you should probably go no higher than two spacers or maybe two of the size you have and one thinner one.

Don't understand slamming. Proper fit should be top priority.

It is what we irreverant cyclists call an affectation.

When you look into the top with the 2 spacers on top as you posted, you can clearly see the gap between the top of the 2nd spacer and the top of the steerer tube. Some gap is necessary to establish tension bearing preload when you put the cap on, but this gap is already a bit large:



Now, when you put the spacers back under the stem, the gap is between the top of the stem and the top of the steerer tube. If you add the 3rd spacer under the stem, it simply makes that gap taller -- in your case, it's dangerously taller since it pushes the top of the steerer below the highest clamp bold. I wouldn't ride it like this.

On a forum where "proper fit" is a near religion, it seems counter productive to arbitrarily "slam" the stem for the sake of looks.

Ah, the conundrum that is The 41!

^ This seems to make sense.

Consider the stem to be a very tall spacer. It can hide the actual height difference between the steerer tube and the stem+spacer stack. The danger is that the stem needs to clamp more steerer tube than less. I have started cutting my steerer tubes too long on purpose so I need to use a spacer above my stem. This way I know that the stem is clamping 100% steerer tube.

As far as slamming your stem goes, if it works than do it. Fit is a relatively, fluid thing, and as a rider gets more cycling fit the rider will tend to get into a longer, lower position.

The opposite holds true at some point, when various aches and pains (typically from age or severe change in body/fitness) makes a higher, closer position more comfortable.

Slamming stems is just one part of the equation. It's part of the whole equation that includes leg length, steerer tube length, etc. On my bike a slammed stem (on a "short as possible" steerer tube) results in a position that's 3 cm (i.e. 30 mm) too high for me. The counter is that my legs are short so my saddle isn't jacked up to the sky. My saddle/bar difference is something like 8 cm, which is not that much.

Bingo. The only thing that is relatively set in stone is saddle height, which is dictated by leg length and geometry. Everything else is fluid and subject to change depending on fitness and need.

I have six bikes. All of them feature the same saddle height, and even the same saddle. All of them have different handlebars, stem length, bar drop, and saddle setback. They all fit perfectly well; it's just they are built for different things. My track bike, when set up for sprint, is low and short; when set up for mass start, is shorter and taller (different bars, same stem: track drop and compact, respectively; neck cramps tend to result if your position is too low during a long points race). My road fixie is set up much like my track sprint setup but with slightly higher bars and slightly more saddle setback. My two road bikes have similar saddle setbacks, but one has deep drops with a relatively high stem (relatively high bar tops, relatively low drops) and the other has compact bars with a long and very low stem (relatively long and low bar tops and relatively high and short drops). I have another road bike set up for track training with short crankarms, forward saddle, and low and relatively short bar reach. My cross/gravel grinder has very wide, very high, relatively short reach bars.

The point is they all fit and they are all a little different. There is no "perfect fit", rather, there are different fits for different purposes. Aspiring racers (or fitness riders) tend towards "slamming" their stem because a long, low position is good for both aerodynamics and power production, even while it sacrifices comfort to a small extent (to which your body eventually adapts).

Make sure that spacers can be used above the stem as well. For example, Cannondale says not use them above the stem.

See page 15:
https://media.cannondale.com/media/ma...rSixEVO_EN.pdf

Assemble the fork, headset, spacers, and stem without tightening the stem bolts onto the head tube. When the system is assembled, the carbon steerer tube should be 2-3 mm below the top stem. All spacers must be located below the stem and within the maximum stack height as shown. No spacers may be used above the stem.

Its different for every bike though. Fuji recommends a spacer above for their setup.

I was always taught that it was better to have a slammed stem with a positive rise than a riser'ed stem with a negative rise. *shrug*

It makes sense - it's a shorter distance from the stem clamp (around the steerer tube / fork) to the bar. Less steerer tube to expose to potential knocks, bumps, etc. If I could set up my bike any way possible I'd run an 80 degree stem or so, i.e. 7 degree rise.

It's also just easier to buy such a stem. 73 degree stems aren't as ubiquitous.

If you add stack to reach and divide by 41 you get pi, so its ok to slam...

I love it how the guy asks about the obviously too short steerer for the number of spacers that came on his bicycle, yet almost all the answers are about bicycle fitting and the assumption that he is moving the stem for the sake of looks.

You're correct but it is more about just the fork than the whole bike. And more specifically about the type/design/placement of the expander plug used with the carbon steerer tube. If the expander plug is not designed to be used with the stem clamped below the top of the steerer, you can crush and damage the steerer. That is what the prohibition is really all about. I don't think it matters at all with aluminum steerers and star-fangled nuts.

The title of the thread is "slamming the stem." It's not unreasonable to assume the OP was interested in, wait for it, slamming his stem. This is the 41 after all where IMO a lot of people slam their stems that have no business doing so.

@Dunbar, beside the title there's also a whole post explaining what the OP wants to know.

Or should I rephrase myself as "I love it how most people don't read further than the thread title before rushing to respond with some judgmental claptrap."

hey...spacers come in different mm widths....2.5, 5, 10...just get the combination that makes it work...you can even get them in shiny colors, so don't get distracted...and ignore that advice in the assembly manual...it's just a suggestion...kinda like torque settings..

If you don't know what you're doing and why you're doing it, maybe it's best to ask a professional to do it for you?

Or read this, scroll down to "headset assembly" and then "headset adjustment, threadless type": https://www.parktool.com/blog/repair-...eadset-service

When you took the topcap off the stem, there should've been a 2 to 3 millimeter gap between the top of the stem and the top of the steerer tube. If this was true, then when you moved all the spacers above the stem, then the same gap should've been present from the top of the top spacer to the top of the steerer tube. If not, then your fork must've dropped down a bit at some point and you do not have everything assembled properly. Don't ride it until you have it properly assembled and the headset properly adjusted. You could ovalize a metal headtube, crack a carbon headtube, break the steerer, or even break your teeth or face. Ride safe!

It's like putting a sock in your shorts.