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Flattened/ovalized handlebars - are they stiff enough?

3K views 7 replies 6 participants last post by  akropilot 
#1 ·
https://ritcheylogic.com/wcs-streem-2-blatte-road-bar

Take a look at this product (above).

Some road handlebars are flattened a little in order to make them more aerodynamics and give your hands a larger platform. Presumably this weakens the handlebar in the up/down direction.

Are these handlebars stiff enough (and strong enough) to handle the same amount of forces as those whose tubing is circular? I'm talking about a 200+ pound rider who can really pull hard on them in a sprint.
 
#2 ·
I don't have any experience with the bars above but I have the 3T Aeronova Team Stealth https://www.3tcycling.com/road/en/bike-components/handlebars/aeronova-team-stealth/ , really flat tops on my race bike and Zipp SLC2 Zipp - Speed Weaponry | Bars | SLC2 Bar ,round bars on my other bike and I notice more flex with the Zipp's. I weigh anywhere between 205-220lbs depending on how late in the season it is. I have not noticed any flex out of the 3T's and the flex I get with the Zipp's is very little. I think it has less to do with shape and more to do with design and construction. I know there are certain bars designed to have some flex, similar to how bike manufactures design in vertical compliance into their frames.

SS-
 
#3 · (Edited)
I wouldn't hesitate to buy those, being a larger sprinter myself (220-230 clyde sprinter). I'm actually using some old, 2012 or so ritchey WCS Logic carbon bars that have lasted surprisingly well considering how thin they are and how much I've reafed on them in training and racing.

They do flex a little but not horribly and it's far from noticeable while actually riding, more so on the trainer when everything locked into place. Probably the only time i notice it on the road is doing over-geared starts which is supposed to be like strength training on a bike. Sometimes during hill sprints.

I know a pro rider that was on the 35mm bars and stem from deda and he mentioned them being almost too stiff and needed time to adjust to them. I imagine the different would be like going from a slightly flexy frame/wheels to a stiffer race frame/wheels when out of the saddle and yankin on stuff. The stiff bars probably felt more direct in there transmission of arm inputs in the vertical dimension.
 
#5 ·
#6 · (Edited)
You're right to be concerned, since strength of a beam is highly related to the thickness.

I had some TTT Aeronova knockoff bars that broke on a defective cattle crossing. I'm very surprised I didn't fold a rim it was such a shock.

Readers feel free to attribute the break to the fact that these were Asian knockoffs, but I've done a lot of carbon layup work and didn't see anything to indicate that these were faulty in materials or craftsmanship. I'll leave it up to the jury.

However I will make these notes:
- I wouldn't worry about a 200lb rider pulling hard, but I would worry about the instantaneous shock of a large hit like I took, which can be severe from a moment-arm perspective. FYI I'm 155lb.
- The bars failed in compression exactly where you would expect, near the stem where the airfoil shape was still thin and moment was highest. Carbon is much stronger in tension than compression, so the bars will tend to collapse on the underside.
- The bars did not fail catastrophically; things remained attached, I did not go down.
- The break was (IMHO) highly exacerbated by bad placement of cable exits exactly where you don't want them; at the highest compression point in the design. The break exactly traversed these exit holes which presented stress-risers. I will never buy carbon bars again with the exit holes underneath the bars. My new S-Works bars smartly have the exit in the middle of the trailing edge, which has the lowest shear in the 'beam'.
- As far as I know, all TTT Aeronovas, whether legit or knockoff, have the exit holes in the same place.

Here I've broken them apart after removal. Note the break passing through the cable exit hole.
Photograph Monochrome photography Black-and-white Black Monochrome

Black Material property Circle
 

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