but only off road, on road better 40mm 
and better get some supple tires ...
ya, I tend to agree on that. Now that I've spent time on both the larger Supremes, 50 and 42mm (but remember only 45 and 37 for me) the main advantage of the wider ones is that when carrying more load weight than you do, it makes live easier on the rims/panniers, and reassuring that I can encounter a really wide range of surfaces and conditions and feel quite confident due to the larger footprint.
but yes, the smaller ones I have on now have been great on pavement,and quite light at 440g I think, which is a nice bonus.
it's an incentive to lighten up my load!