Ok step


1) put on a real cycling kit, retake video and stop looking at your feet (in landscape mode, obviously)

Woops. Sorry about that -- I'm new to this

Here's an updated video.

https://www.youtube.com/watch?v=VoLInlWEGBo

much better (although we should be able to see your fit as well, looks like the video is angled up a little bit)

i would probably set you up "steeper" in that your body position should roll forward and down. that looks like some sort of ISM you are sitting on, but you are not sitting on it ''correctly.'' i should be able to see the back half of that saddle in the video. you want your "seat bones" to be the only pressure you feel, i.e. the saddle is not hitting you on your pubic bone and it isn't hitting you on the wider rear portion of your seat bones. this will take some sliding back and forth and rolling your hips back and forth to get a feel for where the good spot is.

i think once you are seated comfortably/correctly, you will find that your armpads are WAY too close to you. your body/posture will want more "reach" (horizontal distance of your fit, basically). at the same time your extensions should be slid out quite a bit, they are also way too short. don't grip the extensions. place your elbows in the armpads (once they are moved forward a LOT) and rest your hands on top of your shifters. don't grip anything, gripping only creates tension in your hands which then translates back to your forearms, biceps, deltoids, upper back, neck, etc. less tension is good.

posture is at least half of what makes a good bike fit. the other half is decent contact points.

here is a video i made that illustrates some of those talking points

https://youtu.be/Ahd8YZp7ZQE" frameborder="0" allowfullscreen>

Can you relax your shoulders and neck letting your chin ‘drop’ towards the bars?

Does your left knee track outwards?

Okay, I made some adjustments. And I *think* it is much better.



What do you guys think?

Worlds better. To me, you seem still a bit scrunched/arched as a result of limed hip rotation. If you can't roll forward from this (stick butt out, and roll onto the softer parts of the...uh... "area"), you may explore other saddles that might work better for you. I have seen advice here if you want to experiment how it looks with better rotation, angle the nose of the saddle down. Just don't do too much angle as a permanent solution as that bias too much weight on the pads.

If you rotate more I bet you could gain another 3-4 cm maybe even more of pad reach, maybe a bit of added drop, and have a very orthodox/fast position.

Should it feel like I'm almost going to fall off the seat? Like I'm just barely on it? It's my first time on the ISM saddle, and its a bit different than my normal road saddle.

Would I need to move the saddle back slightly for this? Or just rotate?

It definately feels that way at first, junk out in the open air. If you rotate enough you most likely need to extend either backwards or forwards. Might need to push the cockpit/pads forward or saddle back some. Maybe for the first go put the saddle back and a bit of tilt first since that is an easy single adjustment.

For me the falling off the front of the saddle feeling was resolved more by becoming aware of tightening my core muscles and relaxing my upper body. I still putzed around endlessly with adjustments but after awhile I just got stronger and better acclimated.

---

"They know f_ck-all over at Slowtwitch"
- Lionel Sanders

That's good to hear. I was very close to selling this bike because I thought the fit would never work for me, but it turns out I just wasn't used to it (I'm new to cycling and transitioned from a gravel bike). The ISM saddle definitely hurts my sit bones though, so gotta keep playing around.

Thanks everyone for the help!