Adventure bike rim size

[muzzle]

I've just brought a Husky TE610 and it's got a 2.15" rear rim with a 140 tyre on it. I would just like to know the logic in putting a 2.15" rim on the back of a bike with over 50hp. I am happy with the tyre size but I would have thought the rim should be at least a 2.5" to 3.0". Even the owners manual says it has a 2.5" rear rim. I plan to use it for adventure rides so it will spend most of its life on seal and gravel roads with the odd bit of sand and mud. Is it worth lacing up a wider rim or should I just live with what I've got.

[mouldy]

lace up a 3.00 x 17 onto it to give you the best range of adventure tyres , it's probably running a 140/80 18 on it now which in real speak is a 120/100 18, the 140s a wierdo f.i.m. sizing only found on European (sic) enduro tyres