Just wondering what, if any advantage there is with the OS bar / stem combo. Is it purely a strength / durability thing or is there something else I don't know about?

Stiffness, marketing and compatibility with OS road bars

lol @ "marketing" well done for supplying the standard STW answer.

The way I understand it, and this goes for 1.5 inch head tubes and other OS tubing, is that you can have increased stiffnesss with little or no weight penalty because it means you can reduce the thickness of the material slightly. I am sure someone will correct me on this though.

Yeah you are right Mikey

it looks better!

Thanks guys,

I'll probably just stick with what I've got then as its not going to make much difference to me. My bars are plenty stiff enough and I'm not too bothered about saving 10grams.

it's not just marketing – it actually IS more 'core with OS bars

Anything more than XXC or maybe gently assertive all mountain and you're in trouble if you're on spindly pansy bars. That aren't white.

Stiffness is the big one though I note that some roadie guys are using non-OS because it's actually lighter (I guess that there's a limit to how thin you can make the walls when oversizing).