MIN 

Has anyone noticed a difference going from a 26mm bar to an oversized handlebar (31.8mm) setup? Would you recommend it?

ericm979

No difference in bar stiffness. But at 140 lbs I'm not twisting the bars much. Some who is larger might notice a difference, I don't know.

What I did notice is that with carbon bars, the stem bolt torque needed to keep the bars from moving when hitting a sharp bump is much lower on the 31.8mm bars. It's because the clamping area is larger. My 26mm stem is tightened down pretty hard- more than the 5nm spec'd- to keep the bars from moving, while the 31.8mm stem holds the bars fine at 5nm.

If I was getting new bars anyhow, I'd get the 31.8 bars, especially if they are carbon. I wouldn't get rid of perfectly functional 26mm bars.

DocRay

Aside from claimed weight savings, there is no practical difference.
you have more options now with 31.8

gfrance

Boy is that true. I was in the market for a 26.0 threadless stem for my IRO fixed gear bike. Seemed like everything was 31.8.

CastIron

I have 26's on my CX bike and 31's on my road bike. There IS a difference in stiffness and, of course, comfort from a slightly larger handhold. These differences are subtle, but apparent enough for me to prefer the 31's.

DocRay

Maybe for aluminum, but it makes no sense that the industry shifted to Cf bars, but stayed at 31.8mm.
My prediction: the coolest thing in a few years will be 26mm CF bars.

CastIron

Indeed, I haven't yet indulged in CF bars. Since when do the fashion winds make a lick of sense?

MIN 

I hate this BS. My cross bike has a 25.4 mm bar, fixed gear has 26.0mm and road bike is 31.8mm. Gaw!!!

JiveTurkey

How does a 31.8 mm bar have a larger handhold? Doesn't the clamp diameter--whether 31.8 mm or 26.0 mm--taper down to 23.8 mm rather quickly? I guess some 31.8 mm bars maintain a wide diameter for the bar tops?

MIN 

Carbon OS bars retain the thickness on top. I also retain the thickness from time to time.

JiveTurkey

The 25.4 mm ("MTB") vs 26.0 mm ("Road") difference really bothers me.

JiveTurkey

Nice. Unless, you're referring to maintaining the thickness "on top" for you as well?

MIN 

My thickness is directly proportional the level of inter-bike compatibility in my bike parts. So in this case, not at all.

AEO

I made the switch to 31.8mm since I couldn't find a thomson X2 in 26mm.
My dashboard doesn't fit as well with 31.8mm compared to 26mm.
Also bumps feel a bit more forgiving with 31.8mm.
Also when I measured with my calipers, they're closer to 31.7mm

carpediemracing 

I use all 26.0 except the tandem since I didn't bother changing the bars and I wasn't obsessed with fit on that.

26.0 will put you slightly lower than a 31.8 given the same stem height. I put my stem on with no spacers and look for zero stack height headsets (or integrated) so the 5mm or so might help. Other than that I don't know of any difference. I use old fashioned aluminum bars, Ritchey stems, no problems.

On carbon bars - I've seen guys topple over and end up with two pieces of carbon bar attached by some cable. If their bar didn't break they'd still be in the race. At this point I don't want carbon bars on my bike.

Some bike site (cyclingnews, velonews, pez, mebbe someone else) had a pro's bike featured in the last week or so (perhaps Cavendish's Giant?). Aluminum bars and stem.

cdr

BHBiker

no difference,..its just looks better and more sales to bike companies he he he he

Strong Bad

I just finished putting together a new ZX3 from the group buy.
I found 26mm Ritchey WCS classic bar and a 26m Ritchey WCS stem on sale for about 40 bucks each.
I replaced the stem bolts with ti.
Bar = 230 grams
Stem = 105 grams
335 grams for bar and stem and < $100.
And even though they are only 26mm, I can't bend them.
(seemed like a nice place to save money and weight to me).

schnee

I noticed it on my super-wide handlebars - 48cm Salsa Bell Laps. I'm also 6'-3, 250, so YMMV.

It made a difference, but it wasn't make or break.