I took picture before and after change (before 100 mm 6 deg, after 80 mm 7 deg) but I cannot see any difference. Will I feel it? Some members here told me that 20 mm difference was comparable to two frame size downgrade. I have neck and shoulder pain that I hope I can fix by adjusting the stem length. If 80 mm doesn't help, should I try 70 mm or play with the angle to raise the handlebar?

I can't try my bike until next week-end... I feel the pain only after ~2hrs (approx 50km).

I don't see any difference as well.

try Sports Orthopedics specialist.

This is what you want to look at.

Stem Comparison Tool | yojimg.net

Using your numbers provided you brought your stem closer, but also lower:

Only you'll be able to tell if this worked after riding. However, I've noted that most of the time a short stem will also require a higher stem or the discomfort persists or only changes slightly.

Truthfully, nobody can tell you that it will feel like a 2 frame size downgrade. Only your body can answer that. Try it out and see what it feels like. It may look similar but looks can be deceiving. I switched from a 100 to an 80 when I tore my hip. I just did not have the flexibility anymore. I had the surgery in November and have started riding again. As I have amped up my mileage, I have noticed that I am gaining my flexibility back. In a few weeks, I will go back to my 100 mm stem as I can tell that I am able to reach further on my hoods now.
Let your body tell you what it needs. Sometimes with injuries and age things within our fit change. We are less flexible and etc. It could be that you need to look at different bikes, geometries and sizes.

I can definitely feel a 20mm difference in stems. Only you will know if it was the right decision.

It is hard to believe that you like the old reach for the first 2 hours, and will be able to tolerate a 2 cm shorter stem. That has got to feel cramped. Perhaps you just need some neck and shoulder exercises.

May want to try handlebar width and stack height instead of stem length. If not neck and shoulder exercises.

Thanks, this is something I didn't think of but it makes a lot of sense! I bought the bike used and the guy before me was a bit smaller. I didn't know at that time how a proper fitting was important.

How can you increase the stack height if you don't change the fork? There's already 3 stack under the stem and no extra can be added. I guess the only way would be to change the fork but that's quite expensive from what I've seen.

Neck and shoulder pain after two hours sounds like a conditioning issue. I know I see that if I have not been exercising and I get back on the bike. But if I have been doing even light weights and some very rudimentary neck exercises those pains don't happen or go way after just a few rides.

Now I see here and on other forums that we are to set our bikes with the ideal being no weight on the hands so hands, arms and shoulders don't get sore. I have never bought that for myself. Being bent over so I can travel faster and further on the legs I was born with, even against the wind was the huge breakthrough of my teen years. I fully plan to still be enjoying that freedom in my late years (not all that far away now).

I am very fussy about stem, handlebar and brake lever setup precisely because I plan to spend so much time with real weight on my arms. Lifting weights and accepting the drill of sore shoulders and neck for the first several weeks of getting back into riding is just the penance I have to pay for getting off the bike. (I do raise my stem 1 to 1 1/2 cms when I get back on but this is more for the reality of needing those weeks to get my flexibility back. The reason I will never cut a steerer to the minimum. And why I will always love traditional quill stems where raising and lowering is so easy.)

For me, a too short stem leads to the inability to fully and comfortably inhale by pulling my diaphram down. I find I cannot breath as deeply and suffer a lot more on hills. Also that my back gives me issues. Riding longer stems, I feel I can stretch like a cat and that oxygenated blood is reaching everywhere. I feel far better after rides. Drawback - those first several weeks. Oh well.

Ben

Except, Ben, getting low and/or stretching out doesn't mean putting weight on your hands. That is a misconception.

Get a different stem. Bigger angle. A 30 degree 100 cm stem would raise your bars 4 cms over the 5 degree stem.

If it were me, I'd sketch up on paper the head tube centerline at its angle, the top of the headset, the spacers you have and your current stem. Now you can sketch over that the stem you are looking at and see just what it will do to your handlebar position. All you need is a metric ruler and a cheap protractor. I'll bet a department store's school supplies aisle will have them.

Ben

Depends how flat you are, how much you bend your elbows and how much power you put out. if you are pretty upright, i can see you might not feel it. if you are flat, straight arm rider with lower power - you would feel it.

If you saw how my bar tape and gloves wear and the calluses on my palms, you would know you were looking at real weight being placed on them. Yes, if I had a massive engine, I could generate enough torque to take that weight off. I wasn't given that engine and the engine I was given is now many decades older.

Ben

Your comments perplex me. I think you are operating under a number of gross misconceptions. I have never seen any of those phenomena. Maybe you a holding the bars in a death grip. All I can tell you that a good bike fit implies balanced weight distribution. If you don't have that, it isn't because you don't pedal hard enough or because you are trying for a flat back and stretched out position. It just doesn't work that way.

Unneccessary. www.yojimg.net >bike>web tools>stem calc does it all for you.