Just my two cents (hell, cents are almost worth as much as pennies these days)...

The rear rim on the Tenere is 2.75 (inches), so the biggest on your list (2.5 you say?) might be all right?, but possibly have little if any effect - other than make tyre changing more of a fiddle - as it won't sandwich the bead between the rim lip and lock sufficiently?

I've ridden that bike in desert, on slick-rock and (well, you know, pretty much every type of terrain now) and never needed to air-down lower than 18-20psi - and at that pressure it is very doubtful if a tyre would ever slip, it's only got 48bhp and something like a TKC80 on, right?

I'd say there is little point in running really low pressures (sub 15psi) on a bike like the Tenere - it is heavy (and moreso with luggage as you say), so will need to run slightly higher pressures anyway, and lowering pressure in mud makes little difference I've found - if it's thin and greasy, the bike will still slither around due to the weight, and if it's deep and thick, it will stick get stuck - due to the weight...

If you can find a 2.75 rim-lock for the rear then it might be a nice safety net, but the reason they come in the sizes you list above is because they are really designed for full-on enduro bikes, not adventure tourers...

As for the front, I'd always run around 20psi in that, as a higher pressure will help prevent pinch-flats, and protect the rim from impact damage - there is a lot of weight (and basic suspension) on that bike which can take it's toll on a modest 21 inch front rim.

xxx

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