I am considering purchasing these bars to replace a stock aluminum bar (42cm) on my Orbea Onix. The width of the aluminum bar is fine and feels comfy. I ride casually on weekends and put about 50-70 miles per week on the road. I am 5'10" and 150 in weight.

My issue is the width. I have read where the FSA k-wing runs a little narrow and that some folks actually suggest going to the 44cm. Also, I mostly ride upright on the hoods and only use the drops occasionally.

Thanks in advance.............

I went from a 42 to a 44 when I upgraded from my OEM Cannondale bar to a FSA K-Wing Bar myself.
I immediately noticed the difference in my comfort. It all depends on your personal needs.
From what I've read, a good way to find your size is to have someone measure your shoulder blades.
Or, better yet, go to an LBS and see how a 44cm equipped bike feels when you hold it.
For me, wider was definitely better. BTW, the K-Wing itself was a great upgrade.
Made my rides much much nice. I love mine.
(RE: I'm 5'9" so we might have the same width needs.)

My K-Wing is the older, non Compact version, from 2009/2010.

I went from an Icon alumm 42 to a 42 in this model FSA K-Wing; the Compact version was too "narrow" from tops to drops for me.

I'm currently riding two sets of K-Wings. Both measuring 42cm. They do seem to run a bit narrow but it's never been an issue for me. Maybe the width of the bar makes it seem narrow because it certainly does measure 42 c-c.

Really nice that you could get your framesets to match your K-Wings.

A lot of pros ride with a 44cm bar from center to center. Last year I rode the FSA Compact Wing Al bar in size 42cm and it felt too narrow.
Since I wanted to try a carbon bar and love the shape of the Kwing...both in reach and hook size and shape, I ordered the Kwing compact in size 44cm which measure 44cm from center to center of hooks and 43cm from center to center of hoods where most riders spend their time. It feels perfect plus the slightly wider bars have more room up top. Also, you have the option of either taping the top or not with the Kwing because of internal cable routing if you choose. Initially I didn't tape the top and routed both the derailleur and brake cables through the bar. I re-thought this and decided to route the derailleur cables behind the handlebars and the brake cables through the bar. I did this for the best shift performance with Campy and decided I wanted the top of the bars wrapped. My advice if you are an average to larger male is go with the 44cm bar because it measures a bit less across the hoods.
Hope that helps.
Pics below of the Kwing wrapped up top:

Thanks for the responses.

I measured my aluminum bars across, hood to hood. They show 41cm. From bottom bar end to bar end they are 42c-c. So I am not sure what I will do.

It sounds like the FSA in a 42 would be the equivalent to what I currently have. Plus, I can't find the 44cm in the black carbon, only white. And that bar is expensive. Really don't want to pay 300+ bucks for the 44cm. That one pic of the white bar, however, looks pretty sweet. My Orbea has white trim and I currently have white bar tape. Maybe I can be convinced...............

Thanks again, great pics everyone.

Look around. They are going for about $200. for black 44cm K-Wings.

https://www.pricepoint.com/detail/205...p=195%20FSAKB0

+1...check out Pricepoint.com...got my black 44cm Kwing for $200 shipped a couple of months back.

If you like the feel, stick with it. I don't subscribe to bar width correlating to shoulder width. I know big guys who ride 40cm bars. Also, I am not a bigger is better guy either...smaller can be better on a road bike. To me its a feeling. The 42cm FSA Al wing I had last year felt too narrow, particularly lack of leverage climbing out of the saddle. I have also ridden 46cm bars which I couldn't stand as they felt too wide.
So go with what you like.

Pricepoint rocks!

Thank you all soooo much.

I've got the alloy version of the FSA bars, standard edition. For those who switched to the compact one, did it make a difference for you? ( I don't mean carbon vs alloy, just the reach/drop)

Yes, yes and yes.
Made a huge difference for me (both carbon and compact).
My ride is much better now and I love it.

Thanks! I didn't know there were white ones available until I accidentally saw an ad. Then I knew I had to have it.

Good luck Mark with your new bars. I think the black ones look a bit sharper but my intent was to match it with the white on my Orca.

The "tops" on the K Wing bars are higher than a normal bar. Has anyone found the need to lower the bars by removing a stem spacer to adjust this height differential.

I slammed my bar to the bottom and cut the excessive fork from the top off.
I have no spacers. But that's a matter of personal preference.
One man's normal could be another's "high" or "low".