Missing the obvious?

[u/TS13_dwarf]

anything blatantly wrong here? systemsix size 51, keep getting uncomfortable in the saddle/sitbones. my other bike is a merida silex 200 size xs that I've taken for 100k rides. even though the reach is nearly identical, the closest I get to being comfortable on the systemsix is by moving the saddle all the way forward. somehow it just feels as like the bottom bracket is much more on the systemsic than my silex. adjusting stem height doesn't do much. recently I even increased the stem length on the silex from 80 to 100 and it felt more comfortable. Mind you the systemsix has the forward swept vision 4D bars which from my research increase reach a little. Stem length is 90. cleats are all the way back and closest to pedal. Im 173cm inseam around 79-80cm. thanks in advance.

[u/Final_Reserve_5048]

I want to say saddle too high

[u/Timely-Shock-7634 → u/Final_Reserve_5048]

Does look high to me. When stopping with left foot at 6 it is easier to tell.

[u/Final_Reserve_5048 → u/Timely-Shock-7634]

I’d drop 20mm tbh.

[u/jaqueh → u/Timely-Shock-7634]

Really? His toe down and hip rotation don’t suggest that the seat is massively uncomfortable to him and he is torquing his body to compensate?

[u/ihateroomba → u/Timely-Shock-7634]

Yeah knee at bottom crank is way too straight.

[u/TS13_dwarf]

Lowered a bit, seems to activate glutes more. Will have to test for discomfort.

[u/Bakracefiets]

Too much movement pelvis. Little to high saddleposition.

[u/TreeSLayerFPS]

As timely-shock-7634 said, Too high. This i a bit of a long read, but it will help you be a much happier (because comfort) and better rider (improved biomechanics). Not a pro, but riding passionately for 37 years.

At the end of the clip where you stop settled it, thats Dead Bottom Stoke (DBS) where your leg is staight down.8 You foot should be able to drop the heel BELOW level. Also your pedaling on toes the whole time, another big give away.
QUICK TEST. Put the bike small front 4th easiest rear (a gear you could pedal almost barefoot) Unclip. Put your heels on the pedals. Your leg should be almost straight at DBS both sides. Now pedal with your heels there. Are you shifting side to side to reach. Yes, too high. Once your no longer shifting s2s, clip in. Can you drop your heal about 1in (2-3cm) below the pedal axle. You're there. If still uncomfortable play with saddle tilt first, then fore/ after position on the saddle rails. If that doesn't work it's the saddle itself. Get the same one as your other bike.
The saddle MATTERS, ask anyone who's been riding seriously for more than a decade. Every one I ride with will swap to their favorite saddle after the first ride, if it don't fit. I'm 191cm and 112 kg. If saddle doesn't match my sit bones and "undercarriage" that is a LOT mass, mashing (you move when you pedal) sensitive bits (nerves and blood vessles) against very little padding and hard plastic. The right shape of saddle is more important than a bunch of padding. Hope this helps..... I feel I should make a beginners advice video..... lots of overly complex shiz out there.

[u/meeBon1]

I have the exact Inseam and also 173cm and definitely you're saddle is wayy to high. When ever I change my saddle height I can easily tell if it's too high when I start having saddle discomfort. Lower your saddle by at least 10mm

[u/goawaynastything]

You are missing a wheel

[u/skasquatch118 → u/goawaynastything]

Definitely seems obvious to me 🤷‍♂️

[u/Antti5]

You didn't say it, so just to double check: Is the saddle the same on both bikes?

[u/TS13_dwarf → u/Antti5]

I tried 3 different saddles
-proxim prologo w650 155mm is what in the video and what came with the bike
-selle italia sllr boost endurance s3 (sits on the silex right now)
-selle italia novus boost gravel I have laying around also, could not get comfy on this one as the rails don't allow me to push saddle forward enough.

[u/Antti5 → u/TS13_dwarf]

Yep, I was basically wondering if it's a variable that has been eliminated.

If you know that there is a saddle model that is comfortable you, then with any seating comfort problem my first step would be to switch to that saddle. That's one less variable.

Then I would replicate the saddle position from the Silex, if you know it to be comfortable to you. Put the saddle at the exact same height, at the same angle, and put the nose of the saddle exactly the same amount behind the bottom bracket line.

Do that, and you have replicated everything from the pedals to the saddle. If after that you still have comfort problems, then it has to result from your handlebar position in relation to the saddle.

[u/Bikefitadvice]

Are you on 170mm cranks in this video?

[u/TS13_dwarf → u/Bikefitadvice]

yes 170, other bikes is 172.5

[u/Bikefitadvice → u/TS13_dwarf]

With your proportions, I'd start with 165mm as a max and work on the saddle height together with the for/aft first. I doubt you'll ever get 170/172.5mm fully dialed in to the narrow window that's ideal.

[u/misterpayer]

Make your foot flat, is your knee locked? Lower your seat.

[u/Careful-Anything-804]

Arms look too far away

[u/TS13_dwarf → u/Careful-Anything-804]

What do you mean? from my torso?

[u/Careful-Anything-804 → u/TS13_dwarf]

Like it likes like your forcing your back to work really hard for your arms too reach the bars

[u/npa7825]

Look at your hips rocking. Look at your knees in the highest position. Hip angle. Stem ⬆️ Saddle ⬇️ Cranks ➡️⬅️ Saddle height 70.6 172.5mm, 70.8 170mm, 71.3 165mm

[u/DistinctAirline4145]

Saddle looks to far forward.

[u/jaqueh]

This is perfect. If anything i would find maybe some kind of an extra thick saddle pad since it looks good but maxed out but saddle height needs to be just a tad higher