25.4 vs 31.8

[langer]

i posted this on mtbr, but you fools can surely help me better than they can :D

i'm thinking about switching out my riser bars on my mtb and am confronted with the choice of 25.4 or 31.8 diameters. logic would say that the 31.8 would be stiffer at the bar/stem interface, but be a bit heavier. are there any other differences? going to a 31.8 would mean a change in my stem, which is not a problem. a shameless reason to upgrade is never a bad reason.
thanks
-jon

[skillet999]

that's how the manufacturers pitched the move to the larger diameter - main benefit was increased stiffness. Personally - I like the flex offered by my carbon bar with normal diameter but hey... that's just me - I'm an old man that values shock absorbtion more than the youngin's

[xizangsteve]

I currently have a SIC 3" rise bar with a Truvativ Hussefelt DH stem on my gearie and I can tell you it's STIFF! I'm also 210 lbs, so I like the confidence booster. Steve