Longer stem or setback seatpost?
 

Want to have a bit more space between my butt and handlebars. The options are longer stem and setback seatpost. What are theoretical advantages/disadvantages of both options?

When pushing, I instinctively try to move back in the saddle, so seatpost seems to be better option for me. Current setup - Trek Emonda ALR 4 54cm with 90mm stem.

P.S. I already moved the saddle all the way back.

This is settled science. No opinions about it. Saddle setback is not used to adjust reach. It is a totally independent adjustment. You have to get it right first, then you figure out what stem length you need. What is right for saddle setback? That is a hard one. It is about pedaling efficiency, power output, comfort, avoidance of injury to the legs and hips, etc. I like KOPS (knee over pedal spindle)...look it up. Others don't. Still others start there and use KOPS as a starting point gradually adjusting the saddle fore or aft to optimize their position.

Just try to get perfectly satisfied with your saddle setback without any consideration of where your can reach to in the front. Maybe just put your hand on the bar tops where you don't expect to have a lot of room. Concentrate on your pedaling. Maybe a trainer stand would help. When the saddle is right, then you work on the front end to get the room you need

How tall are you?

5'9", but I have under 30" inseam.

It's tricky art to make sure your weight is properly balanced. I have the same issue as you where I tend to come forward in the saddle a little. It's a habit I got from fixie riding. I saw a video where a guy gets in a trainer and no hands it with his hands behind his back leaning forward. That is where you want to be. Unfortunately for me, I do not have a trainer, so I am going back to the shop that fitted me and tweaking it there. Long torso, shorter inseam like yourself as well.

That is such a crock. Total urban myth. Can't you balance no hands on the saddle at any reasonable setback? What does setback have to do with sitting on a seat with your body forward. It is when you put your hands on the bars that the balance comes into play. You don't want zero weight on your hands. You want some weight on your hands, just the right amount.

All this talk about setting saddle position with regard to a balance point is ridiculous. There is so much more to saddle position than that. The pedaling power output and efficiency far outweigh the balance aspect in importance.

Relax man. I am just speaking of a video that shows how to set the saddle if you are putting too much weight on your hands. I think a lot of it comes down to core strength personally. Adjusting your saddle at the cost of efficiency is clearly never a good idea.I think we all agree on that.

thigh bone length or torso length what you are coping with.. ?

Rpen is correct.

Saddle set back is a function of leg length and determining the proper place to have your saddle in relation to the Bottom Bracket. It has nothing to do with reach or balance.

Figure out where you saddle needs to be first.

Then, if you need to adjust reach, you change stem length.

As for the video of a guy on a trainer leaning forward with his hands around his back, that is only a reflection of his core strength. It has nothing to do with the quality of his fit.

It is tempting to move the saddle to adjust reach; it is cheap and easy. For general riding, saddle setback is a personal choice that comes from experience, but should not be used to adjust reach. However, reach will affect saddle position and saddle fit. The more intensely or long you ride, the more sensitive you will be to these variables.

Forward tends to correlate with easier transitions out of the saddle, more weight on the hands, more use of the knees, lower more aerodynamic position.
Rearward correlates with more use of the glutes, less weight on the hands, more on the sit bones, and a more seated style of riding. The handlebars also would be mounted closer, so you would be more crowded when standing.

There really isn't an optimal position. But if you experiment, you are likely to feel a preference. Just don't let the length of the stem dictate it.

More saddle setback favors the glutes and can make for more power and better endurance due to using more muscle groups.

Less setback gives more open hip angle, & favors the quads, & higher rpms.

I was passed by (& kept up with for a while) a fast group yesterday- mixed ages & genders, but they pretty much all had a long, low set up, lots of setback, & long stems.

This (the sanctity of saddle setback?) is a subject of almost religious conviction for some, that there is one perfect, yet mysterious setback.

On stem length, I am suspecting that may be my issue. I went from 120mm to 100mm but I see a lot of frames like the BMC roadmachine that are my size (52) shipping with 90mm stems. All I have done so far is lower my stem to slammed, which I like the feel of a lot as it helps me ride a little lower. My issue is that I still feel like there is too much weight on the bars, but it got a little better when I slammed the stem.

Shorter stem for fixing balance too forward, reach a little too far? I have a long torso, but shorter inseam of 29. Arm length is 21. So I am starting to think that may be something I should look at.

I think I just read here that it is the other way around. To much weight on the bars means the stem is too short, not too long. At least that is what someone said earlier.

Interesting, I would think that if the bars are a shorter length away you would not have to lean so forward. This part of bike fitting is a dark art for me.

Is 30" your cycling inseam? Cycling inseam is different from pants inseam. If CI really is 30", your torso is a lot longer than todays manufacturers design for. I'm 5' 7" with 30.5" CI, and the square bikes of the last 40 years or so are just too short for me. Getting comfortable may require a looong stem or a custom bike, or...

In the '70s, British makers, and maybe French ones, combined 22" long top tubes with 21" seat tubes (c-t). Also with longer seat tubes; they seemed to standardize on 22" TTs. If you need a 21" seat tube and a long top tube, you might look for a classic (or is it vintage?) British frame in Reynolds 531 and build it up.

The 3rd variable that tends not to be mentioned as often, are potentially handlebars with longer reach. Worth considering if you find the tops of the bars already in an ideal location.

^ This

Are there are guidelines to how you determine the correct set-back then?

I recently changed from a high-rise 105mm stem to a normal 120mm one (flipped up), and also moved my saddle forward 15mm to about 60mm set-back from saddle tip to BB.

I've found that I'm using my quads more, and have to get lower (with a straight back) in order to have a comfortable reach with the longer stem - which are both "good things", I think.

However, the negative is that my balance has been affected. With the saddle more to to rear I could more easily lift my hands from the bars and keep pedalling without shifting forward on the saddle (which causes some discomfort on longer rides). I think this is because there is was some part of the force on the pedals pushing the rider rearward, and so helped maintaini the rearward position. With the saddle forward, if I unweight by hands completely (supporting myself with my core) I tend to slide forward on the saddle or have to increase cadence to keep my butt to the rear.

So I wouldn't say that balance has nothing to do with it. I think it is an important aspect of bike fit that keeps you from sliding forward on your sensitive bits! The alternative is to put more weight on your hands to maintain the position. It's all a compromise.

I'm still not decided whether I like the 60mm or 75mm setback, but I do see advantages to the longer stem. The bike is less twitchy and feels a lot more stable in descents and when riding out of the saddle. I think I can output more power when out of the saddle, and my knees don't get anywhere near the bars. Also, having to adopt a low position with a straight back and relaxed shoulders and arms is going to be more comfortable on the neck & shoulders on a long ride, but possibly at the cost of somewhat reduced saddle comfort (although this may be my particular saddle and not a general rule!).

Heresy!

Ok, so saddle setback sets the balance. I am going to get refitted on mine because the fitter kept telling me that he wanted to mess with my saddle position more. The thing is that with experience, you get more core strength for more aero positions. So I have to keep that in mind as well. Numb hands are a thing that I deal with, but it has lessened over time, which tells me that my technique was off a little early. With a slammed stem, the lower back can get sore, but that also could be a result of new muscles being worked and not necessarily a bad thing.

I am starting to think that going to a shorter stem may have been an abrubt move by my fitter because I said that I had numb hands.

That being said, a frame I am looking at - the BMC Team Machine, ships with 90mm stems at the 51 size.

Currently, I am on a 52 cannondale and my seat height is not that much higher than the stem. I'd say a few inches. So maybe I just need a smaller frame or it is just the design of this one. Still learning about bike geometery and fit, but it matters so much, especially when hitting mile 50 or so for me.

...no. Tilt and personal anatomy pretty much sets your balance in the saddle. Anything else is secondary and of minimal import.

I keep saying that, but it isn't sinking in.

...we're doomed. :(

I find this search for "balance" and weight off the hands amusing. I want the best compromise between efficiency and comfort for the type of riding I will be doing on that bike. If that means going real distances upwind, a more forward position than that "balanced" and weight-off-the-hands one is always better. I have no issues at all riding no-hands on bikes that don't fit the balanced criteria. I solve hand issues with real attention to the details of my handlebars and brake levers. My hands do develop very thick calluses at the base of my palms but I just consider that good, not bad.

Now, the balance issue I do pay attention to is the balance of my weight between the two wheels, but that gets addressed when I buy or have custom made that bike frame. Once I own it, that balance is what it is.

Ben

Are you really this lame? I guess once people start crossing the 10k post mark they find more reasons to be snide on the internet.