CrowSeph

I was looking some review regarding an handlebar and a guy replied me on YouTube that the handlebar He's using is flexing about 5-8mm (the rider weight 80kg and the riding type is aggressive).

How much should a carbon handlebar flex in a normal conditions?
Assuming an high output of watts for example in a final sprinting, how much should an handlebar flex?

maybe the tread is very stupid but for me those millimeters of flexing is abnormal.

​​​​​​

Eric F 

In the days when I was racing at the peak of my fitness, and putting out a lot of watts in a sprint, I preferred a stiff CF handlebar. It probably was flexing, but I didn't ever want to feel that flex in my hands, in those conditions. I'm not doing any max-effort sprinting these days, but I still prefer a firm handlebar feel on my road bike, during hard efforts.

My gravel bike, however, is different. I prefer a little bit of compliance.

I probably didn't answer your question at all.

CrowSeph

Your message is not that useless as you think. Basically you are telling me that a flexing handlebar will make you more insecure during sprints, i'am right?
this let me think

Eric F 

Part of my thinking was that I didn't want any of my power lost to flexing parts. I don't know how much of that is a real concern, but that was my thought. In reality, there was probably a lot more flex than I was aware of.

t2p

how much flex in normal conditions ?

depends on a few variables

interesting read on road handlebar testing :

https://blog.fairwheelbikes.com/revi...dlebar-review/

a little dated - but still good read

t2p

back in the day I ran a Scott Lite Flite bar on my road bikes

lightweight handlebar - and a little ‘flexy’ ... could feel it when you were out of the saddle (especially compared to standard Cinelli handlebar or whatever)

sprinter like you prob would not like this handlebar - but for me it was prob a good thing ... small guy on a stiff Cannondale

tFUnK

Good share. Confirms my own subjective opinion of the stiffness of the Pro PLT. But really, the overall range among those tested were 3.5-5.5mm. I am curious how bars with the old 26.0mm clamp diameters fare.

Chandne

The more the better, for me as a recreational rider. I seek out flexier bars for all my biking- road, Mtn, gravel, and fat snow.

base2 

I can confirm that the FSA Kwing is indeed very flexy. I'd venture to say the point of being too much.

I have 2 obtained at various times under different circumstances.

The first was used on a single ride. Vague, and disconnected are words I would use to describe it. I basically removed it the moment I walk through the door after returning from the ride.

The second bar is on a gravel bike. It completely sucks the life out of the bike in a general sense but it does indeed smooth out rough terrain. On that bike I am squarely undecided. It would shine on cobbles.

I'd say the Kwing is suited to much stiffer rides than I own.

Too much of anything isn't always a good thing.

bampilot06

I have never noticed any flexing on the cervelo carbon bars or the madone slr cockpit. I was never lookin though, didn’t realize that was an issue. I was told to stay away from the amazon bars because they flex a lot. I almost feel like that would be nerve racking if my bars were flexing in a sprint.

terrymorse 

I doubt that bar flex is a terribly big problem when sprinting. The loads you put into the bars during a sprint aren't that high, as you're not really yanking up on the bars. It's more of a side-to-side motion.

I'd be more concerned about turning on a descent. Hitting a hole or bump during a turn might be disconcerting, as the bars would suddenly flex.

Kimmo

The flex only slows you down if there's significant hysteresis associated with it, ie if it doesn't return almost all the energy into the system when it unflexes. And if it saves you energy by isolating you from harshness, you'll be faster over long distances.

Kimmo

To my mind, that's probably more likely to work for you than against you - suspension is good for grip.

Fox Farm

I remember my old Lemond Drop In (Scott I think) from the early 1990s. Super flexy and to my mind back then, this was good for increased comfort. Now, the Ritchey WCS alloy bars that I use are dead stiff as are the 3T carbon bars on another bike; no complaints and a prefered feel for me.