So i slammed my stem today. The difference is not huge but the bike feels kind of weird now. Not in a bad way but just different (well duh...)
I also thought I noticed a reduction in my power output. Spinning created more lactid acid and I could not mash as powerfully. This is of course just going by feel but has someone else noticed the same kind of effect after slamming or am I just imagining things? Or is it just a different kind of strain that my muscles have to get used to?

I'm 6'5" and ride a 61cm crux. The bike still fits but feels kinda smaller. Not cramped but not as big...
Seriously this is very hard to explain since I don't know how this stuff should work.
I wanted to give slamming a go, since it could potentially make me faster. Now I'm not so sure...

I don't want to go back because the bike looks nicer this way so any tips and advice would be welcome.
Thanks in advance.

here's my advice: ride 3 days of just riding (hour to 3 hours of jra) then go out and do some hill climbs and see if you've noticed slower times (i'm talking about 10-20 seconds for every 5 minutes of climbing, 1 second off from your pr does not count as a slower time!), if you notice no real loss in time keep your stem slammed. If you notice a huge difference, un-slam your stem.

slamming your stem won't make you instantly faster like slapping on a pair of deep dish tubulars will. Your body needs to get accustomed to the change in geometry/weight distribution, and if you're not currently flexible enough to maintain a slammed position, then your performance will suffer.

It took me almost six months to get used to a slammed stem, and included stretching and some core work.

Slamming your stem typically increases your reach which can put strain on your back which can take power out of your legs. Can you move your seat forward to make up for the probable increased reach?

I wouldn't slam my stem for power, I would slam it for aerodynamic purposes, which would make power use more efficient.

Isn't that what matters around here ?

Pretty much. How many threads do there have to be about this latest fad being a bad idea?

I have chosen comfort over looks.

^thats why i have tons of drop on my bike. It's more comfortable!

I'm a firm believer in slamming stems. I got rid of an inch of spacers, and riding got a lot better. I pick up a noticeable amount of power going from hoods to drops. For example, if I'm just on the verge having trouble turning over a gear when I'm on the hoods, I can go to the drops and it will be fine. Have to admit it's not really that important to me on most occasions.

The funny thing was that once I removed the spacers my neck and hand issues got a lot less bothersome. I used to get numb fingers on longer rides, really doesn't happen now.

the question is how much drop do you run? I like 4"-5".

Take an intelligent approach when adjusting the height of the bars. Regardless of whether the stem angle is changed or spacers are removed, don't make a huge adjustment all at once and don't forget that you'll get about a 3mm increase in reach for each 10mm that the bars are lowered. If you've been using a +6 stem and flip to minus -6, it will drop the bars by nearly 2cm and increase the reach enough that you might need one size shorter stem. For most riders, it's too large a change to do at once, but I've done it, changing from a -6 to a -17 stem (increasing the drop from 9 to 11cm).

Brilliant decision!

Yeah...this is aways good for a chuckle and the usual BF mantra. Don't want to change it because it looks better.
Slamming the stem to replicate a pro race condition closes the hip angle and for many if not most will reduce power output.
In fact for all riders, riding position is a balance between power output and aerodynamics.
Purpose to slam a stem is for improved aerodynamics. Slamming a stem on a Crux is questionable anyway unless you ride the bike solo around at 22 mph...which you may if a decent rider...but most won't...maybe sustained in a pace line when you don't even need a slammed stem unless pulling and you don't even need it then. The tradeoff is power. Some will want less saddle setback to compensate for closing the hip which affect generally riding comfort and most will ride on the rivet to open up the hip angle to create power in the drops. Many average cyclists lose power just riding in the drops with a recreational un-slammed stem.

If you've got good glutes, lowering the bars will close the hip angle and engage those muscles and give you more power. It's a different riding style. Going from an open hip angle where you are mostly using your quads to a closed hip angle where you are using your glutes might lower your power output until you start developing the proper muscles. On the other hand, the glutes have the potential to be far more powerful than your quads, and you'll never get there until you just bite the bullet and lower your bars.

While closing the hip angle develops power without question...there is a point of diminishing return. This point of diminshing return for the average rider even occurs when going from hoods to the drops. Many don't generate as much power in the drops...but they are of course more aero.
It depends how closed the hip angle is to begin with. Further closing the hip angle by slamming the stem will many times lower power output.
Pros want to ride aero. If a typical pro rides with 100mm of drop, he may be more aero with 120-140mm of drop. But...he might not generate as much power. So there is a balance between aero position and power generation depending on hip angle.
Brian, if your thesis was correct all TT bikes would have a laid back road bike sta to further close the hip angle when riding aero. They don't. TT bikes have a more upright seat tube than road bikes in an effort to open hip angle to allow getting into a lower position...a balance between aero profile and power.

I've found this to be true. Even using a large 9-11cm drop, when I hit some of the steeper sections of mountain road and want more power, I drop my torso angle lower and use the glutes.

There is a point of diminishing returns on anything. Obviously you can't really get any more closed than your thighs hitting your chest. After that you start arching your back to get your torso out of the way of your legs and you lose power. Individual riders can tolerate different amounts of drop. To generalize over "most" riders is a bit of a fools errand, particularly when you start talking about trained vs. untrained in a low position. Obviously, doesn't matter what is best, if you never train in the drops, you probably won't produce as much power when you go to the drops. As you train more, most people can tolerate and start to prefer more bar drop.

For aero, if you get lower you get more aero. There is no maxima in that equation. Given that there is a maxima in power production given hip angle, then obviously at some point, you get into a tradeoff situation.

Well good. You understand the concept of diminishing return. The OP has struck it. Re-read his post. He has lost power by slamming his stem.
This is common among amateurs because of what I stated. A given rider with too closed a hip angle for his flexibility will lose power. Of course a rider can improve. Improvement is the point of training...including improving range of motion and generating more power when riding more aero.
PS: as to an equation maxima relative to riding aero...it doesn't have much to do with handlebar height. Riders ride more to their level of flexibility in terms of torso angle more than how high or low their handlebar is. I ride will all kinds of guys with bars too low for their flexibility and they ride straight armed with a pedestrain torso angle.
A high handlebar never slowed down nor kept former hour world record holder Graeme Obree from riding aero either...below:

OP...post a simple metric. Measure your saddle tip to handlebar center line where the stem attachs.
The biggest issue I see on this forum for riders unhappy with their position transcends drop really. I see it for both comfort bikes and slammed bikes....too short a cockpit. Lets see where you fall.

My only point is there is a difference between diminished point of potential return, and actual return. It is sometimes hard to suss out which is which. If one never trains with a slammed stem, then it should surprise no one that his power drops in that position. But with some training, then he might gain higher ground over a lesser bar drop.

Then throw in the whole physiology of body adaptation. If you train using a position that stresses your quads over your glutes, then you'll be a "quad" rider and will perpetually make less power as the hip angle closes. If you train your glutes, then you might actually get more and more power out of your position as you close your hips, right up until your thighs hit your chest.

You pick up a guitar and suck at it; does this mean you aren't a guitarist? Or does it simply mean you don't have practice? You get a back-of-the-B-ride rider and he sucks at the drops, does this mean he'll suck forever, or does it simply mean he doesn't have practice? Everyone sucks when they first try something. The thing that makes them not suck is to encourage them to experiment and try things out. Everyone sucks when they first pick up a guitar. The curious ones, the driven ones, are the ones that get good at it. Same with the bike. Everyone sucks when they first get on a bike. The ones who are willing to experiment with rider position and the extremes of power production and bike handling are the ones that eventually get good at it.

Sitting here at the internets, there is not one thing anyone can tell the OP about his actual riding position. All we can do is pass along philosophies and information wrought from personal experience and research that can help the OP make decisions about what to try.

OP, if you want some decent remarks about your specific setup, please post a picture of you on your bike.

Good points...training makes us all faster. Actually this debate wages on Tri forums about quad versus glute rider. Btw I am a glute rider without a slammed stem. Check out Graeme Obree's bike above.
Again, slamming a stem may or may not have anything to do with how closed your hip angle is. Pelvis angle is influenced and not dictated by saddle position relative to BB center and torso angle. I can ride almost flat backed with virtually no saddle to handlebar drop for example...my arms are bent alot of course.

I found that I had to really experiment with my drop to find where I was fastest. 6" of drop and I was slower due to too much power loss, 3" of drop I made much more power but was still not that fast due to aero penalties. The answer for me seemed to be 4.5" of drop.

Also, FWIW, I train 70% of the time in my 4.5" of drop position, much of that time stretched out even further on aerobars (hip angle probably 85 degrees), and the instant I go back to the hoods I can make more power. I could probably train that position all I wanted, but I'd still make more power by opening up that angle a bit.

One of these days I'll get a TT bike.

here is something else to consider, what about a milder drop but a longer reach? I kind of do that on my 58cm. My head is not down so much as my whole upper body is stretched flatter. My back can tolerate the reach but I feel it more in the tricep shoulder area as more of my weight is closer to the center away from the seat and bar. kindof like this lance pic.

posture by El-Carpaso, on Flickr

Ok, thanks for the input so far. It has given me lots to think about.
Here is a quick picture of my cycling posture on the hoods. Now you might notice that the bike looks really small. This is because I am a fairly big guy and at my size 700c wheels start looking very small on a frame. Secondly there is a bit of angle distortion. The picture should have been taken from the same level where my bum is, but since it was raining we didn't have time to adjust angles. So it's taken from head level which makes the bike look tiny.

But even though the bike looks small, it really is not. I'm not too far ahead since the handlebar covers the front hub when I look down, I don't feel cramped and in my opinion all the angles look kinda right. Ok, of course the top tube could be a lot longer but I don't feel comfy on a longer bike. Believe me, I've tried.

One of the reasons why I felt a loss of power is that I noticed my saddle was way back and nowhere near the KOPS. So I moved the saddle forward and up (2cm forward and 1cm up). Moving the saddle really gave me a lot of power back. But I imagine that I could get rid of the spacers at some point to get even lower. I know I can manage it with time since I'm still quite young and adaptable.

The reason for this really was to find the optimal position between aero and power output to maximize speed. It would seem it will be a long journey...