Body position for checking sag

I've always been taught and seen the pros setting sag sitting in a neutral spot on the bike, foot on the pegs with someone holding the front of the bike.

Attack position. Reason being thats the position you should be riding in. If all your weight is on the pegs like it should be, i dont see a big difference in race techs method vs the attack position tbh. Really tho, does it matter? Either way will get you close to your target number. From there you adjust for preference.

I know one thing, that number seems to vary a insane amount. Yeah people claim this and that about +/- 2mm but suspension stiction throws a wrench into that accuracy.

Where you sit matters a whole lot less than the necessity to do it exactly the same way every single time you take the measurement.

I stand on the pegs with no weight on the handlebars because it's the most repeatable way to measure.

Think of sag as a starting point, not a destination. Set it standing on the pegs (at least 1/2 tank fuel, helmet & boots).

It doesn't need to be dead on. You should finalize the setting by how it feels on the track.
Once you find the sweet spot for you on that particular track, measure the sag again and write it in your notebook.

If you find that you prefer a sag setting (on the track) that is more than 10mm away from the range suggested by the manufacturer, magazine, suspension shop, etc. you need to look at several other factors like body position, fork tube height in the clamps, etc. You shouldn't have to set your sag to some crazy number to make the bike handle well.

Each full turn of the preload ring is about 3mm of sag change on most modern bikes.

If you want to learn your bike:
1) Start with the suggested sag setting, ride a few laps and pay attention to the corners.
2) Reduce the sag to suggested - 3mm (tighten the spring nut 1 turn) and go ride a few laps.
3) Increase the sag back to the suggested (1 turn less pre-load) and go ride a few laps.
4) Increase the sag to suggested + 3mm (1 turn less pre-load) and go ride a few laps.

With those four steps, you'll really gain an understanding of why it's important to find your own sag setting.

Agreed with above. If you sit or stand, it’s just a starting point. I always sit because then I can reference that and know it’s my baseline. In the end it’s all about the feeling.

Best thing you can do is to buy a Motoslacker sag scale.

You will quickly learn how body position impacts sag. It is sensitive to where you sit, but not upper body position. I have to fold upper body 10-15" to have a variance of 1-2mm.

I sit on the bike, feet on pegs slightly behind starting position, kind of neutral. You should not be in exaggerated attack position or any other position to much fwd or back, because that is not where you in average ride.

"Body position for checking sag."

I think it is best done while standing....or jumping.