Most of the detailed bike fit stuff is related to road bikes and sitting down.

I’m curious as to how different length limbs and torso may affect the reach on a mtb?

Say the difference between a person with long arms and legs and a short torso, and a person with short legs and a long torso.

Ideas?

Lots, take in seat angle too…
Also standover is lower on bikes too

Seat angle has no relation to reach though.

depends how tall you are compared to the frame size and how you measure it. Long legs and a slack SA and you will be further back.

depends how tall you are compared to the frame size and how you measure it. Long legs and a slack SA and you will be further back.

I think we are talking about different things………

how different length limbs and torso may affect the reach on a mtb

You need to consider your build also. Build and limb length combined is what guides your position, since a good position is mainly about weight distribution and getting that nicely balanced feel, both your balance between the contact points and then the balance of you between the wheels. ie formula-driven bike fitting may work for sat-down roadies on 73 parallel bikes but it has no bearing on mtbs or anything else needing a more ‘dynamic’ fit, imo. Edit, having said that, I was thinking of how much difference swinging your hips fore/aft or side to side can make to your balance so maybe fit on an mtb isn’t that exact anyway, just get into a comfy middle ground.