Carbon bar flex - what's normal

[schred]

Doing full sik wheelies in the driveway last night I noticed the bar flexing a bit.

I put a string on it and just sitting there I can visibly flex the bar: ends towards each other, or up or down, by ~0.5cm in any direction, or combo ~1cm fore/aft, up & down.

It's this one https://www.3tcycling.com/mountain/en/bike-components/mtb-bars/riser-740-team-stealth/

What's normal? I know all bars flex and carbon moreso, but this seems a bit OTT.

Didn't notice this on the old easton bar.

Hate to think how much it's flexing downwards when the front is nearly bottoming out.

Edit:
Many bars tested >710mm deflected 6-10mm with 50pounds of load applied to one side
http://blog.fairwheelbikes.com/reviews-and-testing/mountain-bike-handlebar-review/

 

[bowtajzane]

how wide are your bars?
wider =more flex ?

 

[John U]

Easy way to view bar flex is flip the bike upside down, stand on the grips on one side and twist the wheel. Don't destroy your shit doing it, but if you have another bike to compare it to it should give you some idea of what's normal.

 

[schred]

It's only 740, but yeah the test above stated the biggest impact on deflection is length, although diff in the real world its not as put material where it needs to be to suit the length, not a theoretical cross section extrapolated over X length.

John U - cheers, will compare to another alloy bar. Be amazed if they are even close, and if I'm not losing feel given the bar. Maybe it has no impact other than mental preference.

 

[will2]

Depends what they are. The test I do is to spin the bar so its parallel with the top tube and press on it.

I had fat bar Lite's and they flex a lot.
My Giant Carbon DH whatever don't do that much.
I don't think you will die.

 

[link1896]

Did these bars come from a reputable seller that can give you some sort of assurance they are genuine?

At one point everything on Alliexpress was branded as 3T, though it seems Raceface is the current flavour.

 

[schred]

Yeah came from pushys, but on sale enough I'm ok with ditching.

I've moved from safety fears to what does this do for ride and feel. I rode an alloyed bar demo bike a few weeks ago and thought the cockpit felt awesome. Same bar height and width, great feedback and front end stiffness through the bar. So I suspect it does have a noticeable effect on trail. Obv a tradeoff at some point. Shame some manufacturers refuse to include their bars in the deflection tests.

Cheers Will, I have a new thing to do at bike shops to their handlebars.

 

[stirk]

I like the sound of these flexy carbon bars and how they might relieve the stress your wrists go through when riding so the wrists are fresh for other pursuits.

Anyone had a carbon bar break clean causing a bad crash?

 

[Mywifesirrational]

I like the sound of these flexy carbon bars and how they might relieve the stress your wrists go through when riding so the wrists are fresh for other pursuits.

Anyone had a carbon bar break clean causing a bad crash?

I've seen two bars last summer snapped with a resulting crashes. Nothing bad crash wise yet.

Both times there snapped were the inner grip clap was, I'm guessing user error and tightening the clamps too tight.

 

[Nautonier]

There was an interesting thread on carbon bars recently where all the carbon nay-sayers came out of the woodwork and much paranoia was to be had:

http://www.rotorburn.com/forums/sho...to-Replace&highlight=time+replace+carbon+bars

After breaking off my relationship with Enve (and My Mountain) for good, I'm still rocking my old and scratched carbon bars and they haven't broken yet. They flex a bit, but this is a positive feature as it provides extra dampening to the ride. When I get back on alloy bars it feels like there is something wrong with the suspension...

 

[schred]

Did the upside down flex test on wifes bike with the oem 300g alloy bar. Zero flex. I have a spare 740mm alloy bar so will throw it on mine and take for a spin. Only the 3rd bar in a week, sick, I love resetting the cockpit.

I had an alloy bar tear off at the stem a long time ago, rode home for 30mins with 1/2 the hbar in place & dislocated shoulder, I'm sure todays stuff is 10x better in any case but it's always in the back of my mind. The idea of single clamp grips on carbon bars seems like a semi-sh1t idea to me, but prob cheaper to manufacture.

 

[nzdans]

Interesting thread..

Can't quantify shit but can say:

Flexiest bars I've ridden were some old Easton Monkey lites, scared me too much, even at 660mm
Next wet noodlest - S-Works, stock 680mm
Next 3T teams, came stock at 680mm
A touch stiffer (but love em!) Renthal Carbon lites, at anything from 680 to 740, all good for me
I have a couple of different sets of Enves, from 690 to 740, stiffer than the above, couldn't really appreciate the 'give'

Bend potentially influenced things a bit for me as I enjoyed riding the alloy versions of my Renthals.

Hmm, I have a set of Carbon Lites on the shelf, must fit them to something...

 

[schred]

I recall Easton bragging in recent years one of their new bars was stronger than the old monkeylite dh, so take it you didn't buy one? ha

I do think you (I) can feel the difference in buzz riding between alu and carbon after 5mins of descent, I'd def like something with less give than current one. Will bend some bars mid week at the local shop.