Handlebars: Aero vs Round.

Discuss light weight issues concerning road bikes & parts.
amngwlvs
Posts: 144
Joined: Fri Apr 20, 2018 2:45 pm
Location: Barrie, Ontario

by amngwlvs

rides4beer wrote:
Wed Apr 17, 2019 1:41 pm
amngwlvs wrote:
Wed Apr 17, 2019 1:14 pm
Thanks for the reply. Really liking these! If only Bontrager made a 1 1/4"stem so I could have a matching stem and bars. :cry:
I have the Kalloy Uno stem (that's what in that pic), it matches pretty well (with the logos removed of course).
It's a good looking stem, unfortunately only seems to be available in 1 1/8" though.
2018 Giant TCR Advanced Pro 0 Disc
2015 Giant Propel Advanced 2
2013 Trek 520

by Weenie


rides4beer
Posts: 172
Joined: Wed Nov 28, 2018 5:27 am
Location: SC

by rides4beer

amngwlvs wrote:
Wed Apr 17, 2019 2:27 pm
It's a good looking stem, unfortunately only seems to be available in 1 1/8" though.
Oops, missed that part.

Sock3t
Posts: 223
Joined: Mon Jun 11, 2018 2:20 am

by Sock3t

I went with the Pro Vibe Aero Superlight. It's almost as light as the non aero bars and is aero. I like that it doesn't have the weird sweep a lot of aero bars have.

It's a nightmare when it comes to stems and computer mounts, though.

Js2
Posts: 109
Joined: Mon May 08, 2017 6:55 pm

by Js2

I have the regular Vibe Aero on my tarmac, comes in around 240 g if I remember correctly. While it says it is both electronic and mechanical groupset compatible, the routing for mechanical is a bitch to get right. The drilled holes are barely big enough for the 2 cables to pass through, and the edges of the hole scuffed up my cable housings too...

Go di2 if you are going the pro vibe aero route. GPS mount is only limited to 1 model made by K-edge for Pro, no combo mounts. The grip area for the mount is so small and curves right away after the stem, making using other gps mount impossible.

However I do love the way they sweep the handle bar and the size + shape of the aero tops is just perfect for me! The shape of the drops are a little weird at first, but now I don't really feel it anymore. :thumbup:

amngwlvs
Posts: 144
Joined: Fri Apr 20, 2018 2:45 pm
Location: Barrie, Ontario

by amngwlvs

Js2 wrote:
Wed Apr 17, 2019 5:11 pm
I have the regular Vibe Aero on my tarmac, comes in around 240 g if I remember correctly. While it says it is both electronic and mechanical groupset compatible, the routing for mechanical is a bitch to get right. The drilled holes are barely big enough for the 2 cables to pass through, and the edges of the hole scuffed up my cable housings too...

Go di2 if you are going the pro vibe aero route. GPS mount is only limited to 1 model made by K-edge for Pro, no combo mounts. The grip area for the mount is so small and curves right away after the stem, making using other gps mount impossible.

However I do love the way they sweep the handle bar and the size + shape of the aero tops is just perfect for me! The shape of the drops are a little weird at first, but now I don't really feel it anymore. :thumbup:
The Garmin mount is a bit of a concern for me. I just bought the combo version of the K-Edge last season and I'd rather not have to replace it already. The Pro Vibe stem is my front runner and then either Pro Vibe or the Pro PLT Ergo bars. I'm having a hard time find a single brand that makes a 1 1/4" stem and aero bars that would suit a TCR so I may go with an ergo bar instead.
2018 Giant TCR Advanced Pro 0 Disc
2015 Giant Propel Advanced 2
2013 Trek 520

Lemke144
Posts: 1
Joined: Sat Jun 16, 2018 11:24 pm

by Lemke144

onemanpeloton wrote:
Wed Apr 10, 2019 9:35 am
Personal preference probably trumps most things here. I like aero tops because I spend a lot of time with my hands there, and round bars just feel too thin. I use giant integrated stem/bar on my tcr and it is super stiff.
I agree with this. I prefer aero bars because there's more surface area for your hands to rest on. I don't go fast enough to take advantage of the watt savings but my hands are happier. Plus aero bars look cool.

dim
Posts: 529
Joined: Fri Oct 13, 2017 11:25 am
Location: Cambridge UK

by dim

Lemke144 wrote:
Sat Apr 20, 2019 7:39 pm
onemanpeloton wrote:
Wed Apr 10, 2019 9:35 am
Personal preference probably trumps most things here. I like aero tops because I spend a lot of time with my hands there, and round bars just feel too thin. I use giant integrated stem/bar on my tcr and it is super stiff.
I agree with this. I prefer aero bars because there's more surface area for your hands to rest on. I don't go fast enough to take advantage of the watt savings but my hands are happier. Plus aero bars look cool.
If you cycle with your hands on the top of the bars, the handlebars are possibly too wide for your shoulders .... I also used to spend a lot of time on the tops when cycling long distances .... I've now bought a narrower bar and my hands are on the hoods for most/all of the time ....

it has made a huge difference, (comfort... no more aches and pains in my hands or shoulders on long rides)

I saw a youtube video where they showed you how to measure your shoulders and get the correct handlebars .... get someone to measure your shoulders at the front .... centre to centre of the middle of the joints ..... this is the dimension of the bars that you require (centre to centre). My previous handlebars were a 42cm and I'm now using 40cm .... although it's only 2cm, it has made a huge difference

I have an integrated aero bar aswell and have saved a lot of grams
Last edited by dim on Sat Apr 20, 2019 8:39 pm, edited 1 time in total.
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HenHarrier
Posts: 33
Joined: Mon Jan 01, 2018 10:34 am

by HenHarrier

I replaced my cervelo aero bars with prime primavera bars from wiggle. I loved the cervelo shape but horrible for trying to add lights etc when the days are short. I really like the prime bars: not as stiff in the drops but I'm not a sprinter so doesn't worry me. I think they look good and came in at 235g for the 42cm. And unless money is of no concern (it is for me) the price is really good too.

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integration
Posts: 19
Joined: Wed Feb 19, 2014 11:08 pm

by integration

Sock3t wrote:
Wed Apr 17, 2019 3:47 pm
I went with the Pro Vibe Aero Superlight. It's almost as light as the non aero bars and is aero. I like that it doesn't have the weird sweep a lot of aero bars have.

It's a nightmare when it comes to stems and computer mounts, though.
I'm looking at getting the vibe aero superlight, are you using them with di2 or mechanical? How are they in terms of stiffness?

Sock3t
Posts: 223
Joined: Mon Jun 11, 2018 2:20 am

by Sock3t

integration wrote:
Sun Apr 21, 2019 3:24 am
Sock3t wrote:
Wed Apr 17, 2019 3:47 pm
I went with the Pro Vibe Aero Superlight. It's almost as light as the non aero bars and is aero. I like that it doesn't have the weird sweep a lot of aero bars have.

It's a nightmare when it comes to stems and computer mounts, though.
I'm looking at getting the vibe aero superlight, are you using them with di2 or mechanical? How are they in terms of stiffness?
It's STIFF. I came from the cheap Alloy Specialized bar. Using it with R9150 (Di2, rim brake) and the bar end junction. I can't notice a difference in flex between the two bars at all.

I did have to get the pro vibe stem and the K-edge mount for the pro vibe.

rides4beer
Posts: 172
Joined: Wed Nov 28, 2018 5:27 am
Location: SC

by rides4beer

Lil update after a couple hundred miles on the new bars. One thing I really like is that the drops are flared. I've never been really comfortable in the drops on two different sets of bars (both straight drops), but now with the flare, the drops are much more comfortable. Guess it's like they say, just gotta try some different stuff and see what works for you.

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cyclespeed
Posts: 631
Joined: Mon Jun 06, 2016 8:45 am

by cyclespeed

3T Aeronova LTD is a great bar.

Light, stiff enough, nice shape and plenty aero. Comfy on the tops. Can pass the Di2 cable through.

2 things; a) an aero bar has a much lower cross sectional area than a round bar, and
b) it has a MUCH better Cd.

It's a win win. A round bar is one of the worst shapes possible aero wise.

It's really a no brainer to change to aero bars unless you're a big powerful sprinter.

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onemanpeloton
Posts: 277
Joined: Wed Jul 12, 2017 11:30 am
Location: Edinburgh, UK

by onemanpeloton

dim wrote:
Sat Apr 20, 2019 8:00 pm
Lemke144 wrote:
Sat Apr 20, 2019 7:39 pm
onemanpeloton wrote:
Wed Apr 10, 2019 9:35 am
Personal preference probably trumps most things here. I like aero tops because I spend a lot of time with my hands there, and round bars just feel too thin. I use giant integrated stem/bar on my tcr and it is super stiff.
I agree with this. I prefer aero bars because there's more surface area for your hands to rest on. I don't go fast enough to take advantage of the watt savings but my hands are happier. Plus aero bars look cool.
If you cycle with your hands on the top of the bars, the handlebars are possibly too wide for your shoulders .... I also used to spend a lot of time on the tops when cycling long distances .... I've now bought a narrower bar and my hands are on the hoods for most/all of the time ....

it has made a huge difference, (comfort... no more aches and pains in my hands or shoulders on long rides)

I saw a youtube video where they showed you how to measure your shoulders and get the correct handlebars .... get someone to measure your shoulders at the front .... centre to centre of the middle of the joints ..... this is the dimension of the bars that you require (centre to centre). My previous handlebars were a 42cm and I'm now using 40cm .... although it's only 2cm, it has made a huge difference

I have an integrated aero bar aswell and have saved a lot of grams
Thanks but that's not the case, the bars are the correct width. I used the method you prescribed for choosing them. However it could be argued that I favour that position because my reach is too long. Either way, the beauty of drop handlebars is the range of hand positions possible (including on the tops) so it makes sense for all those positions to be as comfortable as possible.
2017 Giant TCR Disc
2015 Giant TCX
2016 Cube Stereo 140

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cyclespeed
Posts: 631
Joined: Mon Jun 06, 2016 8:45 am

by cyclespeed

Cyclists often quote the mantra, "handlebar width = shoulder width", but this is only a very rough guideline. If you are comfortable going narrower then do so, as there are gains to be had. Clearly track cyclists are not using the 'shoulder width' equation, for example.....

by Weenie


youngs_modulus
Posts: 575
Joined: Wed Sep 20, 2006 1:03 am
Location: Portland, OR USA

by youngs_modulus

:welcome:
cyclespeed wrote:
Mon Apr 22, 2019 6:03 pm
It's a win win. A round bar is one of the worst shapes possible aero wise.

It's really a no brainer to change to aero bars unless you're a big powerful sprinter.
I would actually go a little further and say that aero bars are a no-brainer especially if you’re a big, powerful sprinter. That is, if you’re trying to win by being the fastest over the final 200 meters, you’re literally drag racing: you’re competing to see who has the highest power-to-drag ratio.

To maximize that ratio, a sprinter must train to produce more power. But the cool thing about power-to-drag ratios is that reducing drag by 100 watts is just as good as increasing power by 100 watts. A smart sprinter will maximize power through training and reduce drag through position changes and equipment choice.

Lots of people find it more intuitive to say that stiffness and low weight seem more important in a sprint. Insofar as I’m sprinting against those people, I fully endorse this point of view:
  • While stiff bars definitely feel “sprinty” and efficient, frame and component compliance don’t absorb very much energy* at all. Compared to a round bar, an aero bar saves a lot more watts than it “costs” in hysteretic losses.
  • While lower mass means faster accelerations, accelerations in bicycle racing are very small. A car that goes from 0-60 mph in 5.5 seconds averages about 0.5 g. A driver accelerating briskly from a stop to merge onto a highway might average about 0.25 g (0-60 in 11 seconds). But a bike racer covering the last 200 meters in 13 seconds (while accelerating from about 28 mph to 38 mph) averages about 0.035 g. That acceleration is an order of magnitude less than a car pulling away from a green light.
In short, sprinting is primarily about terminal velocity. (Tactics and psychology have a lot to do with it too). You increase your terminal velocity by raising your power and lowering your drag. So a smart sprinter will train hard (more power), work to find a low, compact position for sprints (drag) and use sleek equipment—including an aero-section drop bar—to reduce drag.



* I’m the engineer who worked with Fairwheel on some of their stiffness testing. (Fairwheel did the testing and I helped analyze the results). For the crank test, I performed an FEA analysis on a crank to get at strain energy, which is the amount of energy stored by the crank under a given pedaling load.

The stored strain energy represents an upper bound for losses: regardless of how much stored energy gets “returned” to the drivetrain as useful work, the cranks can’t dissipate more energy than they store.

I modeled what was essentially a 1980s Super Record crank to see how much energy it stored under pedaling loads. I chose that crank because it’s very flexible—much more so than modern cranks. Ignoring the question of how much stored strain energy gets turned into propulsive motion, the crank only stored a small amount of power compared to the rider’s total power output. Modern cranks are stiffer than my (intentionally conservative) model, which means they store/absorb less energy than I calculated. Flexing bars take smaller force inputs and store even less energy than cranks.

If you’re worried about “power transfer” (which has no formal meaning in engineering or physics) you should stay away from anything made of carbon fiber. Carbon bars damp vibration by turning motion into heat—and they do that regardless of whether the motion comes from road vibration or from a sprinter’s biceps. The degree of damping usually depends a lot on frequency, but if two bars are equally stiff, the carbon bar will dissipate more energy than the aluminum one. That said, I use a carbon bar on my road bike and I’m not worried about the tiny losses from hysteresis.

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