Fat Bike Q-Factor Quriosity

[ElHardeen]

Re-tooling my Salsa Mukluk for daily driver snow/ice use.

At one point was riding this almost every day on shorter commutes, and even did a three day trip on it this time last year.

At the end of the three day trip, noticed pain on the insides of my knees by the last day. Not sure if this was specifically because of the wider BB, or just the result of a long day spent on pavement with aggressive snow tires.

Have seen a few Fat Bikes coming onto the market using standard 73mm BBs, marketed as better for the knees. This appeals mostly for the ability in using more commonly source-able parts, but curious if there are long term benefits.

Curious if I'm falsely attributing that knee pain to a wider BB since I'm looking for it, similar as someone spending hundreds upgrading their bearings for ceramics noticing a night and day difference, despite a measurably negligible difference.

My question is; has anyone spent extended time riding fat bikes with a wider (~170mm) bottom bracket, and if so, did you notice any odd knee pains?

Really enjoy having one of these in the stable, the terrain they open up for exploring is quite interesting.

[CNY rider]

Timely for me, as I just got back from a fantastic ride on a mix of plowed and unplowed frozen dirt roads on my fattie.
I don't notice the wider Q. as far as I can tell.
But I wonder about your crankarm length? When I start commuting on my winter mountain bike, with long for me 175 crank arms, I get knee pain in the same place.
Just a thought.